Top Banner
Long Life Dairy, Food and Beverage Products White Paper
32

Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

Mar 09, 2018

Download

Documents

hoangnguyet
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

Long Life Dairy, Food and Beverage Products

White Paper

Page 2: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

22000-06-01-2013-G B2

Long Life Dairy, Food and Beverage Products

TABLE OF CONTENTS

Executive Summary 3

Introduction to SPX Flow Technology 3Vision and commitment 3Customer focus 3

Introduction to long life dairy, food and beverage products 4

Microbiology 5Bacteria 5Spores 6Enzymes 6Moulds 7Yeast 7Bacteriophages 7Toxicity 7

Process classification 7Pasteurisation 7Extended shelf life 8UHT treatment 8Sterilisation 9EU classification 9

Process evaluation 9The logarithmic reduction of spores and sterilising efficiency 9Terms and expressions to characterise heat treatment processes 10Residence time 12Commercial sterility 12Chemical and bacteriological changes at high temperatures 12Raw material quality 12Shelf life 13

Choosing the right process 13The heat treatment processes 14Plate heat exchangers 14Tubular heat exchangers 15Corrugated tubular heat exchangers 15Steam injection nozzles 16Steam infusion 16Scraped surface heat exchangers 17

Various aseptic UHT systems 17Indirect Plate Steriliser 17Indirect Tubular Steriliser 19Spiratherm® 20Steam Infusion Steriliser 21High Heat Infusion Steriliser 22Instant Infusion Pasteuriser 23Steam Injection Steriliser 24Scraped Surface Heat Exchanger Steriliser 25Pilot UHT Plant 25Sterile Tank 26Deaerator 27

Extended shelf life/ESL 27The Pure-LacTM process 27

Comparison between different systems 28

Process controls 28

Filling and packaging 30

Product development 30

Page 3: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

3 3 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

VI S ION AN D COM M ITM E NT

SPX's Flow Technology segment designs, manufactures

and markets process engineering and automation

solutions to the dairy, food, beverage, marine,

pharmaceutical and personal care industries through its

global operations.

We are committed to helping our customers all over the

world to improve the performance and profitability of

their manufacturing plant and processes. We achieve this

by offering a wide range of products and solutions from

engineered components to design of complete process

plants supported by world-leading applications and

development expertise.

We continue to help our customers optimise the

performance and profitability of their plant throughout its

service life with support services tailored to their individual

needs through a coordinated customer service and spare

parts network.

CUSTOM E R FOCUS

Founded in 1910, APV, an SPX Brand, has pioneered

groundbreaking technologies over more than a century,

setting the standards of the modern processing industry.

Continuous research and development based on

customer needs and an ability to visualise future process

requirements drives continued mutual growth.

Executive Summary Introduction to SPX Flow Technology

There are a number of important microbiological factors

that need to be addressed in the production of long

life dairy, food and beverage products. The presence of

microorganisms in the milk must be reduced to a safe

number in order to ensure sufficient shelf life under

appropriate storage conditions.

This can be achieved by a variety of thermal processes.

The efficiency of these processes is a factor of

temperature and holding time and can, if not properly

controlled, lead to adverse effects on flavour and

appearance.

A number of systems of relevance to the dairy, food and

beverage industries are discussed and advice is offered

on how to achieve the best quality product at a reasonable

cost, taking into account safe and trouble-free operation.

Efficient aseptic processing is an important factor in

development of new products. The SPX Innovation Centre

in Denmark offers Pilot Plant Testing and application

solution guidance services to help customers maximise

the performance of their plant. Pilot Testing can also be

conducted on customers’ own premises based on rental

equipment and, if required, with support from SPX experts.

Page 4: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

4 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

Introduction to long life dairy, food and beverage productsAs one of the most complete food products of all, dairy products

are very important in human nutrition. However, dairy products are

also highly perishable and would easily lose their nutritional value,

flavour and appearance if protective measures were not taken.

Consequently, the dairy industry is one of the most advanced

industries in the food processing area, taking care of the

milk from when it leaves the udder of the cow - through

transportation to the dairy, processing, packaging, and

distribution - until it reaches the consumer.

The technology of producing long-life products is today applied

throughout the food and beverage industries and in many cases

the processing plants are designed for multipurpose operation.

When aseptic technology was introduced more than 50 years

ago, it revolutionised the food industry by making it possible to

distribute high quality food products over long distances in a

cost-effective way.

The heart of aseptic technology for production of long-life

dairy products is aseptic processing, and since its introduction

this concept has been developed and refined to a point where

any need in respect of capacity, product viscosity, particulate

content, acidity or sensitivity to heat treatment can be met while

securing high quality, long-life products.

SPX Flow Technology was one of the pioneers in aseptic

processing and over the years we have developed a wide range

of processing concepts to satisfy all the needs of the industry.

In this publication, we will first discuss some of the micro-

biological factors, which must be considered in all aseptic

processing, together with the heating processes most

commonly used for reducing micro-organisms in dairy products:

pasteurisation, sterilisation and ultra high temperature (UHT)

treatment.

So-called commercial sterility is the aim of all UHT processes,

and the extent to which this is achieved in a particular process

can be measured, notably by reference to the bacteriological

effect (B*) and the chemical effect (C*) of such processes.

These factors are explained in the section “Process Evaluation”.

The main part of the publication is devoted to an analysis of

the processing systems of most interest to the dairy, food and

beverage industry: Indirect Plate Steriliser, Indirect Tubular

Steriliser, Steam Infusion Steriliser, High Heat Infusion Steriliser,

Instant Infusion Pasteuriser, Steam Injection Steriliser and

Indirect Scraped Surface Heat Exchanger (SSHE) Steriliser.

In each case we describe the system, discuss its advantages

and limitations, and list a number of products for which the

system in question is particularly suitable (See Tables 1 and 4).

The Pilot UHT Plant is able to combine most of the aseptic

processes in one unit, which provides an efficient tool for pilot

trials and product development.

In aseptic processing, special consideration must be given to

some of the auxiliary equipment required. Aseptic tanks are not

a necessary requirement but often serve as a useful buffer for

sterilised products.

The area of extended shelf life products is becoming

increasingly important, and the development of the Pure-

LacTM concept is offering the industry and the consumers new

solutions and exciting opportunities.

With the large number of options available it becomes important

to be able to choose the solution, which provides the best

quality product at a reasonable cost, giving safe and trouble-

free operation. A separate section has been made to cover this

subject.

The process control system is not only necessary, it must

incorporate up-to-date technology - not least on the software side.

Special attention must be given to the subsequent filling and

packaging of aseptically processed products.

Finally, we address the area of product development. SPX

Flow Technology’s world wide capabilities in respect of product

testing makes it possible to work closely with customers in their

efforts to upgrade production and launch new products.

This publication is purely dealing with the indirect and direct

heat transfer processes.

SPX Flow Technology is also manufacturing various types of

electrical - or “electroheat” thermal processing equipment. This

is dealt with in a separate publication.

Page 5: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

5 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

TAB LE 1: A VAR I ETY O F DAI RY, FO O D AN D B EVE RAG E P R O D U CTS

AN D TH E I R S U ITAB I L ITY FO R TR EATM E NT I N TH E R MAL H EAT

P R O C E S S I N G SYSTE M S.

MicrobiologyThe key to production of long-life products with aseptic technology

is a detailed understanding of the microbiology of food. Using

the example of the dairy industry, the milk in the udder of a

healthy cow is free from bacteria, but as soon as the milk comes

into contact with the air it becomes contaminated with micro-

organisms.

If the temperature is favourable, the micro-organisms multiply

and very soon the milk will turn sour (or putrefy), developing an

unpleasant flavour. To prevent this from happening, the raw milk

is sub jected to heat treatment.

The term aseptic is usually defined as “free from or keeping

away” disease producing or putrefying microorganisms. In the

food industry the terms aseptic, sterile and commercially sterile

are often used interchangeably. This is not strictly correct.

Sterilisation means 100% destruction of all living organisms,

including their spores, and this is very difficult to achieve.

Commercial sterility means that the product is free from

microorganisms, which grow and consequently contribute to the

deterioration of the product. Microorganisms are extremely small

and can only be seen under a microscope. However, hundreds or

thousands of individual cells or groups of cells can form colonies,

which are visible to the naked eye, and some colonies have

colours, shapes, textures or odours, which make the organism

identifiable.

BAC TE RIA

The term bacteria strictly means rod-shaped microorganisms

only, but is also used in a loose sense to include all micro-

organisms except yeast and moulds. The individual bacterium

varies in size from 0.5 to 3 micron.

The groups of bacteria, which are most important in the

dairy industry are the lactic acid, coliform, butyric acid, and

putrefaction bacteria. The bacterial count in milk coming from

the farm varies from a few thousands bacteria/ml for high

quality milk to several millions if the standard of cleaning,

disinfection and chilling is poor.

For milk to be classified as top quality, the CFU (Colony Forming

Units) should be less than 100,000/ml.

Bacteria are single-celled organisms, which normally multiply by

binary fission, i.e. splitting in two. The simplest and most common

way to classify bacteria is according to their appearance and

shape. However, in order to be able to see bacteria, they must

first be stained and then studied under a microscope at a

magnification of approximately 1,000 X.

DAI RY, FOOD & B EVE RAG E PROD UCTS

PL

AT

E S

TE

RIL

ISE

R

TU

BU

LA

R S

TE

RIL

ISE

R

ST

EA

M I

NF

US

ION

S

TE

RIL

ISE

R

HIG

H H

EA

T I

NF

US

ION

S

TE

RIL

ISE

R

INS

TAN

T I

NF

US

ION

P

AS

TE

UR

ISE

R

ST

EA

M I

NJE

CT

ION

S

TE

RIL

ISE

R

SC

RA

PE

D S

UR

FA

CE

HE

AT

EX

CH

AN

GE

R S

YS

TE

MS

M I LK X X X X X

M I LK (F LAVO U R E D) X X X X X

M I LK (EVAP O RATE D) X X X X

M I LK (C O N C E NTRATE D) X X X X X

M I LK (S HAK E M I X) X X X X X

C R EAM X X X X X

C R EAM (WH I P P I N G) X X X X

C R EAM (SYNTH ETI C) X X X X X

YO G H U RT X X X X

YO G H U RT (D R I N K I N G) X X

YO G H U RT (F R U IT) X X

Q UAR K P R O D U CTS X

S OYA M I LK X X X X X

BABY FO O D X X X X

I C E C R EAM M I X X X X X X

C H E E S E D I P S X X X X

P R O C E S S E D C H E E S E X X X

D E S E RTS / P U D D I N G S X X X X

WH EY P R OTE I N C O N C. X X

C O F F E E WH ITE N E R X X X X X X X

E G G-BAS E D P R O D U CTS X

SAU C E X X X

S O U P S X X

C O F F E E / I C E TEA X X

F R U IT J U I C E X X

Page 6: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

6 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

Based on a method of staining, developed by the Danish

bacteriologist Gram, bacteria are divided into Gram negative

(red) and Gram positive (blue). The three characteristic shapes

of bacteria are spherical, rod-shaped and spiral. Diplococci

arrange themselves in pairs, staphylococci form clusters, while

streptococci form chains.

Another way of classification is according to temperature

preference:

• Psychrotrophic bacteria (cold-tolerant) reproduce at temperatures of 7°C or below.

• Psychrophilic bacteria (cold-loving) have an optimum growth temperature below 20°C.

• Mesophilic bacteria ( loving the middle range) have optimum growth temperatures between 20°C and 44°C.

• Thermophilic bacteria (heat-loving) have their optimum growth temperatures between 45°C and 60°C.

• Thermoduric bacteria (heat-enduring) can tolerate high temperatures - above 70°C. They do not grow and reproduce at high temperatures, but can resist them without being killed.

Bacteria can only develop within certain temperature limits,

which vary from one species to another. Temperatures below

the minimum cause growth to stop, but do not kill the bacteria.

They are, however, damaged by repeated freezing and thawing.

If the temperature is raised above the maximum, the bacteria

are soon killed by heat. Most cells die within a few seconds of

being exposed to 70°C, but some bacteria can survive heating

to 85°C for 15 minutes, even though they do not form spores.

A third way of classifying micro-organisms is by their oxygen

requirement. The availability of oxygen is vital to the metabolism

of all organisms. Some bacteria consume oxygen from the

atmosphere; they are called aerobic bacteria. However, to some

bacteria free oxygen is a poison; they are called anaerobic

bacteria and obtain the oxygen they need from chemical

compounds in their food supply. Some bacteria consume free

oxygen if it is present, but they can also grow in the absence of

oxygen; they are called facultatively anaerobic.

The acidity of the nutrient substrate for bacteria is also

important. Sensitivity to pH changes varies from one species to

another, but most bacteria prefer a growth environment with a

pH around 7. Furthermore the salt and/or sugar concentration

of a substrate has an important influence on the growth of

bacteria. The higher the concentration, the more growth is

inhibited. This is caused by the high osmotic pressure, which

will draw water out from the cell, thereby dehydrating it.

Osmotic pressure is used as a means of food preservation in

sweetened condensed milk, salted fish and fruit preserves like

jam and marmalade.

S POR E S

The spore is a form of protection against adverse conditions,

e.g. heat and cold, lack of moisture, lack of nutrients, or

presence of disinfectants. Only a few bacteria are spore

forming e.g. Bacillus and Clostridium. The spores germinate

back into a vegetative cell and start reproduction when

conditions become favourable again. The spores have no

metabolism and can survive for years in dry air and are much

more resistant to adverse conditions than bacteria. This

includes heat treatment and it takes typically 20 minutes at

120°C to kill them with 100 percent certainty. The UHT time/

temperature combination reduces the number of bacteria

spores by a minimum of log 9, leaving very few bacteria spores

in UHT treated products.

E N ZYM E S

When the milk leaves the udder it contains enzymes, the

so-called original enzymes. Enzymes are also produced by

the bacteria in the milk, the so-called bacterial enzymes.

Enzymes are not micro-organisms but are formed as a result

of the metabolism of micro-organisms. The ability of enzymes

to trigger chemical reactions can be important when UHT

products are produced.

Page 7: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

Temperature

Time

135ºCPure-Lac TM

85ºCHigh pasteurisation

72ºCLow pasteurisation

7 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

Some of the bacterial enzymes are able to cause sweet

coagulation of milk products, which destroys the product. The

majority of these enzymes are produced by Gram negative

Pseudomonas bacteria developing mainly in cold raw milk

stored for excessive time in milk cooling tanks, road tankers

or milk silos. This problem will be aggravated if the milk has

been contaminated because of unhygienic conditions or lack

of cleaning-in-place (CIP). The vast majority of enzymes will be

destroyed by UHT treatment, but a few may still be active in the

final product.

MOU LD S

Moulds belong to the fungi group of micro-organisms, which

are very widely distributed in nature among plants, animals and

human beings. Moulds normally grow anaerobically, and their

optimum growth temperature is between 20 and 30°C. Moulds

can grow in substrates with pH 2 to 8.5, but many species prefer

an acid environment. The most common species in milk do not

survive pasteurisation conditions, and the presence of mould

in pasteurised products is therefore a sign of reinfection. The

penicillium family is one of the most common types of moulds.

Their powerful protein splitting properties make them the chief

agent in ripening of, for instance, Blue Cheese.

YEAST

Yeast also belong to the fungi group of micro-organisms. They

vary greatly in size. Saccharomyces cerevisiae, used for brewing

of beer, has a diameter of 2 to 8 micron, but other species may

be as large as 100 micron.

Yeast has the ability to grow both in the presence and absence

of oxygen. The optimum temperature is between 20 and

30°C. Optimum pH values are 4.5 to 5.0, but yeast will grow in

the pH range of 3 to 7.5.

From a dairy point of view, yeast are generally undesirable

organisms. They ferment milk and cream and cause defects

in cheese and butter. In the brewing, baking and distillation

industries, on the other hand, they are very valuable

organisms.

BACTE R IOPHAG E S

Bacteriophages belong to the group of micro-organisms

called viruses. Viruses have no metabolism of their own and

therefore cannot grow on a nutrient substrate. Viruses infect

living cells in plants and animals. Bacteriophages (also known

as phages) infect bacteria and are consequently a problem in all

dairy processes where bacteria cultures are used. They are very

small in size - in the order of 0.02 to 0.06 micron and can only

be seen in an electron microscope.

Bacteriophages grow at temperatures between 10 and 45°C.

They are killed by exposure to 63 to 88°C for 30 minutes and

tolerate pH values in the range of 3 to 11.

TOXICITY

Micro-organisms, which are harmful to man or animals are called

pathogens. They can cause death or severe illness by the secretion

of toxins either directly into contaminated foodstuffs, which are

subsequently eaten, or by transfer to an animal host offering ideal

conditions for reproduction and further generation of toxins. Some

toxins are inactivated by heat treatment at 60°C for one hour.

Process classificationA number of different expressions are commonly used in the

food industry in relation to food preservation. This section will

briefly describe the most common terms used.

PASTE U R I SATION

Most commercial liquid food products undergo some form of

heat treatment, and pasteurisation is the most common. As

it is usually bacterial growth that causes food to deteriorate,

pasteurisation preserves the freshness of the food product.

There are basically two ranges of pasteurisation:

• Low-temperature pasteurisation. For milk, this is based on heating the product to 72 to 76°C and holding at that

F I G. 1: LOW-TE M P E RATU R E PASTE U R I SATI O N

Page 8: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

ºC150

100

50

010 20 30 40 50 60

Minutes

0

50

100

150

Time

ºC

Direct Infusion

High Heat Infusion

Indirect UHT

8 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

temperature for at least 15 to 20 seconds (or equivalent) (Fig. 1). The pasteurisation may vary from country to country according to national legislation. A common requirement in all countries, however, is that the heat treatment must guarantee the destruction of unwanted micro-organisms and all pathogenic bacteria. The shelf life of pasteurised milk is limited (typically 5 to 7 days) and primarily depends on raw milk quality and storage temperature. During the low-temperature pasteurisation the phosphatase enzyme is destroyed, while the peroxidase enzyme is preserved. This serves as a measure to control the process and distinguish it from high-temperature pasteurisation.

• High-temperature pasteurisation. This is based on heating the product to 85°C or higher for a few seconds (or equivalent) (Fig. 1). The aim is to kill the entire population of bacteria, which are pathogenic for both man and animals and almost all other bacteria as well. By careful monitoring of the process parameters a product with excellent quality can be obtained with minimum heat damage. The shelf life can be extended to several weeks in the cooling chain. The so-called Pure-LacTM process is based on high-temperature pasteurisation. During the high-temperature pasteurisation both the phosphatase and the peroxidase enzymes are destroyed, and this serves as a measure to control that the process has actually taken place as specified.

EXTE N D E D S H E LF LI FE

The term extended shelf life or ESL is being applied more and

more frequently.

There is no single general definition of ESL. Basically what

it means is the capability to extend the shelf life of a product

beyond its traditional well-known and generally accepted shelf

life without causing any significant degradation in product quality.

A typical temperature/time combination for high-temperature

pasteurisation of ESL milk is 125 to 130°C for 2 to 4 seconds.

This is also known in the USA as ultra-pasteurisation.

SPX Flow Technology has in recent years developed a patented

process where the temperature may be raised to as high as

135°C but only for fractions of a second. This is the basis for the

Pure-LacTM process described in a separate chapter, see table of

contents.

U HT TR EATM E NT

UHT - or Ultra High Temperature - treatment is based on the

fact that higher temperatures permit a much shorter processing

time. By proper time and temperature combination it is possible

to achieve commercial sterility with only limited undesirable

chemical changes in the product. In terms of nutritive value,

flavour and appearance, the quality of the product is more

vulnerable to the duration of the treatment than to the

temperature applied.

In the UHT process, the milk is typically heated to 137 to 150°C

and held at that temperature for just a few seconds before it

is cooled rapidly down to room temperature (Fig. 2). After the

product has been cooled it is led to an aseptic filling machine in

a closed piping system - either directly or by way of an aseptic

storage tank. The product obtained in this way has a shelf life at

room temperature of several months.

The quality of the final product depends on the raw material

quality but also to a large extent on the type of heat treatment

system applied. This is the case for UHT milk and for a wide

range of long life food products like sauces, salad dressings,

mayonnaise and soups, as well as for juices and soft drinks.

F I G. 3: TE M P E RATU R E P R O F I LE S FO R C O NVE NTI O NAL I N-C O NTAI N E R

STE R I L I SAT I O N

F I G. 2: TE M P E RATU R E P R O F I LE S FO R D I R E CT I N F U S I O N, H I G H H EAT

I N F U S I O N AN D I N D I R E CT U HT P R O C E S S E S.

Page 9: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

9 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

TAB LE 2: P R E S E NT LE G I S LAT I O N AC C O R D I N G TO E U D I R E CTIVE 92/46 * * I D F & E U S U G G E STI O N S FO R D UAL C H E M I CAL C R ITE R IA

In order to combat the Heat Resistant Spores (HRS) SPX Flow

Technology has developed the patented so-called High Heat Infusion

system enabling heat treatment temperatures as high as 150ºC

without adversely affecting the product quality and still maintaining

acceptable running times in the order of 24 hours between cleaning.

Products with very high viscosity are more difficult to handle in a UHT

system, and SPX Flow Technology has developed a special patented

version of the infusion system to handle high viscosity products.

This so-called Instant Infusion system is based on very short but

controllable and well defined retention time in the infusion chamber.

STE R I LI SATION

Sterilisation is another type of heating process used for products to

increase keeping quality without refrigeration. The heat treatment

takes place after the product is packed. The package with its

content is heated to approx. 120°C and held at that temperature

for 10 to 20 minutes after which it is cooled to room temperature

(Fig 3). Because of the lengthy heat treatment at a relatively

high temperature this process reduces the nutritive value of

the product, and it is also liable to change its colour and flavour

considerably.

E U CLASS I FICATION

In the EU Milk Hygiene Directive (92/46) it is suggested that “limits

and methods to enable a distinction to be made between different

types of heat treated milk” may be established (Article 20).

The proposed parameters, limits and methods may be

summarised as shown in Table 2.

By this method the hygienic requirements concerning food safety

can be satisfied taking into consideration the keeping qualities

over varying length of time. This method also makes it possible to

establish a new definition of different types of fluid milk products

in a way that is independent of the technology of the heat

treatment and the filling such as for instance, Pure-LacTM.

It should be noted that the chemical criteria in Table 2 are the

recommendation given by IDF and EU to the legislators, but the

general perception is that this proposal will be followed.

Process evaluationAll UHT processes are designed to achieve commercial sterility.

This calls for application of heat to the product and a chemical

sterilant or other treatment that render the equipment, final

packaging containers and product free of viable micro-organisms

able to reproduce in food under normal conditions of storage

and distribution. In addition it is necessary to inactivate toxins

and enzymes present and to limit chemical and physical changes

in the product. In very general terms it is useful to have in mind

that an increase in temperature of 10°C increases the sterilising

effect 10-fold whereas the chemical effect only increases

approximately 3-fold. In this section we will define some of

the more commonly used terms and how they can be used for

process evaluation.

THE LOGARITHMIC REDUCTION OF S POR E S

AN D STE R I LI S I NG E FFICI E NCY

When micro-organisms and/or spores are exposed to heat

treatment not all of them are killed at once.

However, in a given period of time a certain number is killed

while the remainder survives. If the surviving micro-organisms

are once more exposed to the temperature treatment for the

same period of time an equal proportion of them will be killed.

On this basis the lethal effect of sterilisation can be expressed

mathematically as a logarithmic function:

M I LK HYG I E N E D I R ECTIVE 92/46/ E U

TH E R M I S E D PASTE U R I S E D H IG H TE M PE RATU R EPASTE U R I S E D HTP U HT STE R I LI S E D

63 - 65ºC/15 S E C. 71.7ºC/15 S E C.O R E Q U IVALE NT >135ºC AN D >1 S E C. >135ºC AN D > 1 S E C.

P H O S P HATAS E+ P H O S P HATAS E-P E R OX I DAS E+

P H O S P HATAS E-P E R OX I DAS E-

15 DAYS AT 30ºC O R7 DAYS AT 55ºC 0 ⇒

<10 C F U /0.1 M L

15 DAYS AT 30ºC O R7 DAYS AT 55ºC 0 ⇒

<10 C F U /0.1 M L

** * * * * * *

B ETA-LACTO G LO B U LI N> 2600 M G / L

&

B ETA-LACTO G LO B U LI N> 2000 M G / L

&

> 50 M G / L&

B ETA-LACTO G LO B U LI N< 50 M G / L

O R

LACTU LO S EN OT D ETE CTAB LE

LACTU LO S E< 40 M G / KG

LACTU LO S E< 600 M G / KG

LACTU LO S E> 600 M G / KG

Page 10: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

10 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

A logarithmic function can never reach zero, which means that

sterility defined as the absence of living bacterial spores in an

unlimited volume of product is impossible to achieve. Therefore

the more workable concept of “sterilising effect” or “sterilising

efficiency” is commonly used.

The sterilising effect is expressed as the number of decimal

reductions achieved in a process. A sterilising effect of 9

indicates that out of 109 bacterial spores fed into the process

only 1 (100) will survive.

Spores of Bacillus subtilis or Bacillus stearothermophilus are

normally used as test organisms to determine the efficiency of

UHT systems because they form fairly heat resistant spores.

TERMS AND EXPRESSIONS TO CHARACTERISE

HEAT TREATMENT PROCESSES

Q10 value. The sterilising effect of heat sterilisation increases

rapidly with the increase in temperature as described above.

This also applies to chemical reactions, which take place as a

consequence of an increase in temperature. The Q10 value has

been introduced as an expression of this increase in speed of

reactions and specifies how many times the speed of a reaction

increases when the temperature is raised by 10°C. Q10 for

flavour changes is in the order of 2 to 3, which means that a

temperature increase of 10°C doubles or triples the speed of

the chemical reactions.

A Q10 value calculated for killing bacterial spores would range

from 8 to 30 depending on the sensitivity of a particular strain to

the heat treatment.

D-Value. This is also called the decimal reduction time and is

defined as the time required to reduce the number of micro-

organisms to one-tenth of the original value corresponding to a

reduction of 90%.

Z-Value. This is defined as the temperature change which gives

a 10-fold change in the D-value.

F0 value. This is defined as the total integrated lethal effect

and is expressed in terms of minutes at a selected reference

temperature of 121.1°C. F0 can be calculated as follows:

F0 = 10(T - 121.1) /z · t / 60 , where

T = processing temperature (°C)

z = Z-value (°C)

t = processing time (seconds)

F0 = 1 after the product has been heated to 121.1°C for one

minute. To obtain commercially sterile milk from good quality raw

milk, for example, an F0 value of minimum 5 to 6 is required.

B* and C* Values. In the case of milk treatment some

countries are using the following terms:

• Bacteriological effect: B* (known as B star)

• Chemical effect C* (known as C star)

B* is based on the assumption that commercial sterility is

achieved at 135°C for 10.1 seconds with a corresponding

Z-value of 10.5°C; this reference process is giving a B* value of

1.0, representing a reduction of thermophilic spore count of 109

per unit (log 9 reduction).

The B* value for a process is calculated similarly to the F0 value:

B* = 10 ( T - 135 ) / 10.5 · t / 10.1, where

T = processing temperature (°C)

t = processing time (seconds)

The C* value is based on the conditions for a 3 percent

destruction of thiamine (vitamin B1); this is equivalent to 135°C

for 30.5 seconds with a Z-value of 31.4°C. Consequently the C*

value can be calculated as follows:

C* = 10 ( T - 135 ) /31.4 · t / 30.5

Fig. 4 shows that a UHT process is deemed to be satisfactory

with regard to keeping quality and organoleptic quality of the

product when B* is > 1 and C* is < 1.

K · t = log N/Nt , where

N = number of micro-organisms/spores originally present

Nt = number of micro-organisms/spores present after a

given time of treatment (t)

K = constant

t = time of treatment

Page 11: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

2.7 2.6 2.5 2.4 2.3

1T

4000

2000

3000

1000

800900

600700

400

500

200

300

100

80

60

70

90

40

50

20

30

10

8

6

4

5

7

9

2

3

1110100 120 130 140 150 160ºC

loss of thiamine = 80%

threshold range of discolouration

loss of thiamine = 3% / C*=1

HMF 1 µm

ol/l

HMF 100 µmol/l

HMF 10 µmol/l

60%

40%

10%

loss of lysine = 1%

lactulose 600 mg/l

lactulose 400 mg/l

20%

region ofsterilisation

thermal death value = 9

thermophilic spor es / B*=1

UHT-region

Hea

ting

time

or e

quiv

alen

t hea

ting

time

in s

econ

ds

·10 in K3 -1

11 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

F I G. 4: BACTE R I O LO G I CAL AN D C H E M I CAL C HAN G E S O F H EATE D M I LK (H.G. K E S S LE R)

The B* and C* calculations may be used for designing UHT

plants for milk and other heat sensitive products. The B* and C*

values also include the bacteriological and chemical effects of the

heating up and cooling down times and are therefore important in

designing a plant with minimum chemical change and maximum

sterilising effect.

Page 12: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

FromAPV InfusionChamber

ToVacuumChamber

TURBULENT FLOW OF IS WELL DEFINEDLIQUID

V

ToVacuumChamber

SIGHT GLASS

SIGHT GLASS

V1V2

3V

HOLDING TIME NOT DEFINED

V > V > V3 2 1

Holding Tube without Centrifugal Pump

Holding T ube with Centrifugal Pump

From otherDirect UHT Systems

Multi-phase system:

Single-phase system:

12 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

The more severe the heat treatment is, the higher the C* value

will be. For different UHT plants the C* value corresponding to a

sterilising effect of B* = 1 will vary greatly. A C* value of below 1

is generally accepted for an average design UHT plant. Improved

designs will have C* values significantly lower than 1.

The APV Steam Infusion Steriliser has a C* value of 0.15.

R E S I D E NCE TI M E

Particular attention must be paid to the residence time in a

holding cell or tube and the actual dimensioning will depend on

several factors such as turbulent versus laminar flow, foaming, air

content and steam bubbles. Since there is a tendency to operate

at reduced residence time in order to minimise the chemical

degradation (C* value < 1) it becomes increasingly important to

know the exact residence time.

In SPX Flow Technology the infusion system has been designed

with a special pump mounted directly below the infusion chamber,

which ensures a sufficient over-pressure in the holding tube

in order to have a single phase flow free from air and steam

bubbles.

This principle enables SPX Flow Technology to define and

monitor the holding time and temperature precisely and makes it

the only direct steam heating system, which allows true validation

of flow and temperature at the point of heat transfer.

The concept is illustrated in Fig. 5.

COM M E RCIAL STE R I LITY

The expression of commercial sterility has been mentioned

previously and it has been pointed out that complete sterility in

its strictest sense is not possible. In working with UHT products

commercial sterility is used as a more practical term, and a

commercially sterile product is defined as one which is free from

micro-organisms which grow under the prevailing conditions.

CH E M ICAL AN D BACTE R IOLOG ICAL

CHANG E S AT H IG H TE M PE RATU R E S

Heating milk and other food products to high temperatures

results in a range of complex chemical reactions causing changes

in colour (browning), development of off-flavours and formation

of sediments. These unwanted reactions are largely avoided

through heat treatment at a higher temperature for a very short

time, and it is important to seek the optimum time/temperature

combination, which provides sufficient kill effect on spores but,

at the same time, limits the heat damage, in order to comply with

market requirements for the final product.

Even though the time/temperature combination is decisive for

the final quality of the product attention also has to be paid to

the actual heating profile since various reactions take place at

different temperatures. This is illustrated in Fig. 6 in which type

A deposit is a voluminous protein-rich deposit, whereas type

B deposit is a mineral rich deposit developing primarily at high

temperatures. In particular type A deposit, which originates from

protein denaturation, must be minimised since it is harmful to the

product quality.

RAW MATE R IAL QUALITY

It is important that all raw materials are of very high quality as the

quality of the final product will be directly affected. Raw materials

must be free from dirt and have a very low bacteria spore count,

and any powders must be easy to dissolve.

All powder products must be dissolved prior to UHT treatment

because bacteria spores can survive in dry powder particles even

at UHT temperatures. Undissolved powder particles will also

damage homogenising valves causing sterility problems.

Heat stability. The question of heat stability is an important

parameter in UHT processing.

Different products have different heat stabilities and although the

UHT plant will be chosen on this basis it is desirable to be able to

measure the heat stability of the products to be UHT treated.

For most products this is possible by applying the alcohol test. When

samples of milk are mixed with equal volumes of an ethyl alcohol

solution the proteins become unstable and the milk flocculates.F I G. 5: H O LD I N G TU B E

Page 13: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

80 90 100 110 120 130 140

Type A deposit

Deposit build-up

Type B deposit

Temperature, ºC

Inlet to Heater Milk Flow Outlet to Holding Tube

13 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

The higher the concentration of ethyl alcohol is without

flocculation the better the heat stability of the milk. Production

and shelf life problems are usually avoided provided the milk

remains stable at an alcohol concentration of 75%.

High heat stability is important because of the need to produce

stable homogeneous products, but also to prevent operational

problems like fouling in the UHT plant. This will decrease

running hours between CIP cleanings and thereby increase

product waste, water, chemical and energy consumption.

Generally it will also disrupt smooth operation and increase the

risk of insterility.

S H E LF LI FE

The shelf life of a product is generally defined as the time for

which the product can be stored without the quality falling below

a certain minimum acceptable level. This is not a very sharp and

exact definition and it depends to a large extent on the perception

of “minimum acceptable quality”. Having defined this it will be

raw material quality, processing and packaging conditions and

conditions during distribution and storage, which will determine

the shelf life of the product.

Milk is a good example of how wide a span the concept of shelf

life covers:

The usual organoleptic factors limiting shelf life are deteriorated

taste, smell and colour, while the physical and chemical limiting

factors are incipient gelling, increase in viscosity, sedimentation

and cream lining.

Choosing the right processIn order to be able to produce a product with specific product

qualities in the most cost-effective way it is essential to make the

correct choice with respect to processing system and technology.

In many cases the choice is straightforward, but in other cases

there may be more options to choose between. Some of the

more important questions to ask when choosing a system are:

• What is the specification of the product to be processed?

• Which are the quality requirements to the final product?

• Viscosity specifications of products and raw materials?

• Specification of particulate and fibre content/size and shape and variation in content?

• Acidity of product/high or low acid?

• Sensitivity to high temperatures/heat stability?

• Requirement for flexibility/multi-purpose systems?

• Requirement for variable capacity?

• Requirement for direct or indirect systems?

• Skills of technical personnel/operators?

Fig. 7 illustrates three of the selection criteria - viscosity,

capacity and content of particulates - for the most common

processing systems.

The systems are often flexibly designed to allow for processing

a range of products in the same plant.

It is quite common to process both low-acid (pH>4.5) and high-

acid (pH<4.5) products in the same UHT plant.

However, only low-acid products require UHT treatment to make

them commercially sterile.

Spores cannot develop in high-acid products such as juice, and the

heat treatment is therefore only intended to kill yeast and moulds.

Consequently high temperature pasteurisation at 90 - 95°C for

15 to 30 seconds is sufficient to make most high-acid products

commercially sterile.

F I G. 6: D E P O S ITS I N U HT P LANTS.

Product Shelf life Storage

Pasteurised milk 5 to 10 days refrigerated

ESL/Pure-LacTM 20 to 45 days refrigerated

UHT milk 3 to 6 months ambient temp.

Page 14: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

Capacity l/h35.000 l/h

50 cP

200 cP100 cP

50,000 cP

500 cP

Plate Steriliser

Steam Injectio

n Steriliser

Steam Infusio

n Steriliser

Tubular Sterili

ser

SSHE Steriliser

Increasingparticle size

Viscosity cP

14 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

In some cases where new products have to be processed it may

be necessary to carry out trials in small scale to observe the

performance of specific products in different types of systems.

SPX Flow Technology has designed a pilot unit for this purpose.

The trend for processors to focus increasingly on flexibility to

process a range of products and the importance of being able to

produce high quality products has driven the choice of systems

towards indirect tubular systems and direct steam infusion

systems.

The following sections will deal with the various heating

principles and UHT systems followed by a more detailed

comparison of the individual systems.

TH E H EAT TR EATM E NT PROCE SS E S

SPX Flow Technology invented the plate heat exchanger

in 1923 and has ever since pioneered new heat treatment

principles. Scraped surface heat exchangers were developed in

the USA while the direct steam infusion system was developed

in Denmark. The tubular systems were developed partly in

Denmark and partly in Germany and later supplemented by the

corrugated tubular heat exchangers in Spain. In addition SPX

Flow Technology is known for electroheat thermal processing

equipment, which is dealt with in a separate publication.

PLATE H EAT EXCHANG E R S

The plate heat exchanger is the most cost-effective and versatile

method for indirect heating or cooling of liquid food pro -

ducts. Today SPX Flow Technology’s comprehensive Paraflow

range of plates is the basis for a wide range of plate heat

exchanger applications in many industries, and in the food

and dairy industry the plate heat exchanger is one of the most

indispensable pieces of equipment.

As illustrated in Fig. 8.1 the plate heat exchanger incorporates a

number of parallel, closely spaced stainless steel, gasketed and

corrugated plates, which are compressed and locked together

in a rugged frame. As product is pumped through the plate heat

exchanger, the flow is distributed through narrow, corrugated

flow passages, which produce a high level of turbulence

F I G. 7: AS E PTI C P R O C E S S I N G SYSTE M S

Page 15: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

15 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

resulting in high rates of heating or cooling with low hold-up

volume. Product contact time is thereby reduced to a matter of

seconds minimising thermal damage.

A very important advantage of the plate heat exchanger is

its extremely high regenerative capability, reducing energy

requirements for heating or cooling by more than 90%. Plate

heat exchangers provide a maximum amount of heat exchange

surface in a minimum amount of floor space.

TU B U LAR H EAT EXCHANG E R S

SPX Flow Technology has developed a range of sanitary tubular

heat exchangers for the food industry, and an increasing number

of customers choose this system. Various tubular systems are

available, but the most commonly used system is the multi-

tube-in-tube (MTNT) system as illustrated in Fig. 8.2. The heat

transfer modules are multiple small diameter sanitary tubes

aligned within a large diameter shell.

The diameter of the inner tubes may vary, but is usually in the

range of 10 to 12 mm for low viscous products like milk and

juice.

The SPX Flow Technology tubular system is designed with a

“loose” jacket around the tube bundles giving a floating head

design.

This allows thermal expansion without any risk of tube cracking,

prevents stress corrosion and allows easy inspection of all heat

exchange surfaces.

In some countries, e.g. Germany, the tubular system has become

very popular because of its rugged construction and easy

operation and maintenance.

COR R UGATE D TU B U LAR H EAT EXCHANG E R S

SPX Flow Technology has extended its range of heat

exchangers with corrugated tubular heat exchangers. By

corrugating the tube wall it is possible to improve the heat

transfer coefficient and consequently reduce the requirement

for heating surface area. The corrugation causes increased

turbulence and breaks the laminar flow in high viscosity

products.

Double-tube, triple-tube, quadruple-tube and multi-tube are the

basis for the range as illustrated in Fig. 8.3.1, 8.3.2, 8.3.3 and

8.3.4. The design of the double-, triple- and quadruple-tube

makes it possible to arrange direct regeneration because both

sides of the tube wall are a sanitary design.

Through a variety in corrugation depth, pitch and angle it is

possible to optimise heat transfer and pressure drop depending

on shear characteristics of the product. Furthermore, the

possibility of adjusting the annular space adds one further

parameter for optimising the design.

F I G. 8 .3 .1: AP V D O U B LE TU B E

F I G. 8 .3 .2: AP V TR I P LE TU B E

F I G. 8 .3 .4: AP V M U LT I-TU B E- I N-TU B E

F I G. 8 .3 .3: AP V Q UAD R U P LE TU B E

Product in Product out

Media inMedia out

F I G. 8 .1: AP V P LATE H EAT E XC HAN G E R

Media out

Media in

Productout

Productin

F I G. 8 .2: AP V TU B U LAR H EAT E XC HAN G E R

Page 16: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

Air out

CIP in

Holding tube

Steam in Product in

Cooling waterin/out

Steam

Product

16 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

STEAM I NJ ECTION NOZ Z LE S

SPX Flow Technology was one of the pioneers in applying steam

in direct contact with a product to heat it to aseptic temperatures.

The first generation systems were based on the steam injection

principle and were launched under the Uperiser brand name.

The system operates by direct injection of steam through a

specially designed nozzle as illustrated in Fig. 8.4. The injection

of steam raises the product temperature instantly. In order to

prevent the product from boiling it is necessary to pressurise the

product during the steam injection to a pressure of 3 to 4 bar

depending on the sterilisation temperature.

Flash cooling takes place in a vacuum expansion vessel where

the vacuum is maintained by means of a vacuum pump. The

vacuum is controlled in order to ensure that the same amount

of water is flashed off as was injected into the product as steam

thereby preventing dilution/concentration of the product.

STEAM I N FUS ION

In the 1960s APV, An SPX Brand, launched the first steam

infusion system under the Palarisator brand name. Since then

significant developments and progress have taken place, which

have led to one of the most sophisticated systems in the world.

After pre-heating the product is pumped into the infuser, which

is a pressure vessel fitted with cones at both top and bottom as

illustrated in Fig 8.5.

At the top cone the product is distributed through a number

of nozzles (patented) and passes down through a steam

atmosphere in a number of jets without hitting the walls of the

vessel until it reaches the bottom cone.

This is equipped with a cooling jacket keeping the temperature

of the inner cone wall below the product temperature inside the

vessel. This creates a condensate film on the inner cone wall,

which effectively prevents any burn-on of product. During the

heating air, unwanted gases and odours are stripped off through

the CIP inlet at the top of the cone.

The product leaves the infusion chamber through the bottom

of the cone through a pump and an expansion valve before

it passes through the holding tube into the expansion vessel

where the product is cooled down in a similar way as described

for the injection heating system.

As previously mentioned (Fig. 5) this system ensures a single

phase flow and a very accurate flow profile.

The pump and the valve in the holding tube also serve as level

control, which means that there is no product level prior to the

pump and consequently no influence on the holding time due to

varying liquid level at the bottom of the cone, since it will always

be empty.

The heating in the infuser is extremely rapid, and the final

sterilisation temperature is reached in less than 0.2 seconds,

which corresponds to a heating rate of 500 to 600ºC/second.

The system is very flexible and can be used for a wide range

of products covering a broad viscosity range. It provides an

excellent product quality due to the gentle and rapid heating and

subsequent cooling.

F I G. 8 .4: AP V STEAM I NJ E CTI O N N O Z Z LE

F I G. 8 .5: AP V STEAM I N F U S I O N C HAM B E R

Page 17: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

Product out Product in

Media in Media out

17 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

SCRAPED SURFACE HEAT EXCHANGERS

SPX Flow Technology’s product range includes a number

of scraped surface heat exchangers specially designed to

heat or cool viscous or sticky products or products containing

particulates.

The scraped surface heat exchanger consists of a smooth

cylinder through which the product is pumped, counter current to

the service medium in the surrounding jacket.

Rotating scraper blades keep the heating surface free from

deposits. The scraper blades are fixed to a rotating shaft called a

dasher (Fig. 8.6).

Selection of different blades and dasher types depends on the

product being processed. The cylinders are usually characterised

by their diameter and SPX Flow Technology supplies units of 4,

6 and 8 inches.

Furthermore, both vertical (Fig. 9) and horizontal models (Fig.

10) are available.

The most recent addition to the range is a VT+660 model with 0,65

m2 surface area, which is 41 percent higher than for the 4” range.

The maximum operating pressure for the VT range is 6 bar while

the HD range is able to operate at 12 bar maximum pressure.

In terms of viscosity the VT model is able to process

products with viscosity up to 100,000 cP.

The HD range is a Heavy Duty model able to handle viscosity as

high as 500,000 cP.

Various aseptic UHT systemsThe best way to characterise UHT systems is to rank them

according to the primary type of heating principle used for

bringing the product into the aseptic area.

The type of system preferred has developed differently in

different countries at different times. In the following section

we will give a brief description of each type of system available

on the market today. For each system the advantages and

limitations will be emphasised and finally the products most

commonly processed in the system will be listed.

All SPX Flow Technology UHT systems are pre-assembled and

tested in the factory with steam. This minimises installation and start-

up costs and ensures a safe and trouble-free plant commissioning.

I N D I R ECT PLATE STE R I LI S E R

UHT systems based on plate heat exchangers are used where

the manufacturer’s primary requirement is a dependable system

for heating liquid products at minimum operating costs.

In Fig. 11.1 a flow diagram illustrates the principle design

including some of the processing parameters.

Careful design of the heating and regenerative systems

optimises the performance of the SPX Flow Technology system

and minimises product damage. Fig. 11.2 compares some key

data for plate and tubular systems.

PRODUCT FILLING

STEAM

1. Product to productregenerative

2. Homogeniser

3. Indirect heating4. Holding tubes5. Indirect cooling

6. Sterile tank7. Cip unit8. Sterilising loop

COOLINGWATER

31

2

6

7

8

5ºC 75ºC

3 5

CHILLEDWATER

4 490ºC 138ºC

5

<25ºC25ºC

F I G. 11.1: F LOWD IAG RAM FO R P LATE STE R I L I S E R

F I G. 9: AP V VT+660 S C RAP E D

S U R FAC E H EAT E XC HAN G E R

F I G.10: AP V H D S C RAP E D

S U R FAC E H EAT E XC HAN G E R

F I G. 8 .6: AP V S C RAP E D S U R FAC E H EAT E XC HAN G E R

Page 18: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

18 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

The SPX Flow Technology system has a high degree of flexibility

and can be supplied with variable capacity and with two-speed

or variable speed homogenisers.

The system can be built up to a maximum capacity of 25 to

30,000 l/h.

Fig. 11.3 shows a typical design for an APV Plate Steriliser.

Advantages

• Excellent for low viscosity products

• High regenerative effect and low energy consumption

• High heat transfer area in minimal space

• Easy inspection

• Low hold-up volume

• High degree of flexibility

• Variable capacity Large capacity plants

• Relatively low investment

• Low CIP costs

Limitations

• Limited capability for particulates or fibres

• Exchange of gaskets required periodically

• Unsuitable for high pressure drops

• Some product degradation may occur

Products

• Milk, flavoured milk

• Fermented milk products, drinking yogurt

• Cream, coffee whiteners

• Soy milk

• Baby food

• Juice

• Coffee, tea

• Combination plants for milk, juice, coffee, tea, etc.

LOW MEDIUM HIGH

Energy recovery

PLATE

TUBULAR

LOW MEDIUM HIGH

Heat transfer at equivalent surface

PLATE

TUBULAR

LOW MEDIUM HIGH

Product shear at equivalent heat transfer

PLATE

TUBULAR

LOW MEDIUM HIGH

Plant volume at 90% regenerative

PLATE

TUBULAR

F I G. 11.2: C O M PAR I S O N O F DATA FO R P LATE AN D TU B U LAR STE R I L I S E R

F I G. 11.3: AP V P LATE STE R I L I S E R

Page 19: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

19 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

I NDIRECT TUBULAR STERILISER

UHT systems based on tubular heat exchangers have become

popular in many countries and are typically chosen where large

volumes of commodity products has to be processed at the

lowest possible costs.

In Fig. 12.1 a flow diagram illustrates the principle design

including some of the processing parameters.

In Fig. 12.2 it is shown how the pressure drop affects the

maximum running hours. In a plate based steriliser the increase in

pressure drop is limited to 30 to 40 percent.

This is not a limiting factor in tubular systems and 16 to 20 hours

operating time between CIP is possible. It is also possible to

operate with an intermediate cleaning each 20 hours and reduce

the full CIP cycles to once a week, which may increase the

capacity with as much as 7 to 9 percent.

Exact times will depend on particular products and

microbiological considerations.

Advantages

• Less vulnerable to fouling giving long production runs

• High operating pressures are acceptable

• Processes products with fibres and particulates

• Processes high viscosity products

• Low shear characteristics for cream

• Low requirement for gasket material and easy gasket exchange

• Very robust design

• Low maintenance costs

• Can be designed as a multi-purpose plant

• Easy to operate

Limitations

• Lower regenerative effect than for plate sterilisers

• Slightly higher investment costs compared with plate sterilisers

• Higher degree of product degradation

Products

• Milk, flavoured milk

• Fermented milk products, drinking yogurt

• Cream, coffee whiteners

• Whipping cream, ice cream mix

• Evaporated milk, desserts, puddings

• Soy milk

• Coffee, tea

• Juices, juices with pulp

• Salad dressings

• Gravy, sauces, soups

• Combination plants for milk, juice, coffee, tea, etc.

Tolerated pressure drop (bar)0 50 80 90706010 20 30 40 100

Tubular UHTPlate UHT

10 305 252015

Particle sizes/Fibre lengths (mm)

Tubular UHTPlate UHT

Running time (hours)0 84 12 16 20 24

Tubular UHTPlate UHT

240

220

200

180

160

140

120

100

80

Operating Time of Plant [hour]5 10 15 20 25

Tubular UHT

Common practice tube

Common practiceplate

Plate UHT max. limit

Pre

ssur

e in

crea

sere

lativ

to c

lean

pla

nt (%

)

Plant Feed Pressure -Milk Fouling in Tubular UHT Plant

FIG. 12.2: COMPARISON OF DATA FOR TUBULAR AND PLATE STER ILISER

PRODUCT FILLING

4

8

5

10

6

79

5ºC

75ºC

21 1

95ºC 140ºC

25ºC

STEAM

COOLINGWATER

1. Tubular regenerativepreheaters

2. Homogeniser3. Holding tubes

4. Tubular final heater5. Tubular regenerative

cooler6. Final cooler

7. Sterile tank8. CIP unit9. Sterilising loop10. Water Heater

3 3

F I G. 12.1: F LOW D IAG RAM FO R TU B U LAR STE R I L I S E R

F I G. 12.3: AP V TU B U LAR STE R I L I S E R

Page 20: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

20 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

S PI RATH E R M®

APV Spiratherm UHT system is a unique type of process system.

Development of the Spiratherm concept was initiated in the

beginning of the 1960’s based on feed back from the market

place.

Many UHT systems suffer from one or more of the following:

high maintenance costs, contamination risk, limitation in running

time or long CIP periods.

The Spiratherm provides an optimal solution to mitigate all of the

above worries.

Longer operation period

The heart of the Spiratherm system is the unique design of the

tubular heat exchanger.

The natural scrubbing action of the high velocity product through

the Spiratherm heaters cuts down on the product build up found

in conventional heat exchangers.

Spiratherm makes a perfect selection for UHT production of a

wide range of products, including high fouling products.

Reduced CIP time

The tubes are cleaned more easily and less frequently thanks

to CIP capabilities which ensure a minimum of downtime and

greater productivity.

Reduced maintenance cost

The Spiratherm tubes operate more efficiently than coil, plate,

multitube or double-tube methods, allowing faster, more even

heat exchange without hot spots.

Maintenance cost reduction results from the long tube life and

the fact that there is never a need to replace gaskets.

Reduced contamination risk

After sterilisation under high pressure within the sealed Steritherm,

the product travels to a homogenising valve. The valve can be

sterilised and easily cleaned and will maintain sterility. An exclusive

valve stem feature and gauge position assure that no air pockets,

cracks, or crevices can contaminate the product zone. And this

valve, remotely mounted from the pump, eliminates the need for

aseptic homogeniser, reducing lifetime maintenance costs.

No steam / product mixing

The unique heating performance achievable with the Spiratherm

Heat Exchangers assures a rapid heating and cooling time, reducing

any chemical induced impact on the product. In fact, the heating and

cooling profiles are quite similar to those of a direct UHT system.

The Spiratherm differs from direct UHT systems by omitting

direct mixture of product and steam and subsequently the need

to remove the added steam downstream under vacuum.

All Spiratherm models are designed with variable-range

operating capacities for direct connections with fillers operating

at various speeds.

F I G. 12.4: AP V S P I RATH E R M TU B U LAR

Page 21: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

21 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

STEAM I N FUS ION STE R I LI S E R

UHT systems based on the infusion heating are used where the

manufacturer wants to produce a high quality product with as

little heat degradation as possible. Also flexibility in throughput

and variety in product range speak for an infusion based system.

In Fig. 13.1 a flow diagram illustrates the principle design

including some of the processing parameters.

The system can basically be supplied from 150 l/h (pilot plant) to

44,000 l/hour with a temperature profile as shown in Fig. 13.2.

The plate heat exchangers for pre-heating and cooling can be

replaced with tubular heat exchangers as an option.

The SPX Flow Technology infusion UHT concept can also be

supplied as an add-on solution to all common UHT plants from

other manufacturers.

Fig. 13.2 shows a comparison of various temperature profiles for

infusion based processes, which are all characterised by a very

rapid and controlled heating and cooling profile and a short and

carefully monitored holding time.

Fig 13.3 shows an APV Steam Infusion Steriliser.

Advantages• Gentle and accurate heating in the infusion chamber

• Accurate holding time

• Superior product quality

• Closed loop during pre-sterilising

• High product flexibility

• Low fouling rate

• Long operating time

• Operator friendly

Limitations• Relatively higher capital costs compared to indirect systems

• Relatively higher operating costs due to lower heat regeneration

• Requirement for culinary steam

Products• Milk, flavoured milk, creams

• Soy milk products

• Vla, custard, pudding

• Soft ice mix, ice cream mix

• Baby food, condensed milk

• Processed cheese

• Sauces

6 6

143ºC 75ºC 25ºC <25ºC

FILLING

5

7

VACUUM

STEAM

1. Plate preheaters2. Steam infusion chamber3. Holding tube

4. Flash vessel5. Aseptic homogeniser6. Plate coolers

7. Aseptic tank8. Non aseptic cooler9. Condenser

COOLINGWATER

2

STEAM

75ºC

COOLING

COOLING

WATER

WATER

4

9

3

1

PRODUCT

5ºC

8 COOLINGWATER

Various Temperature Profiles for Direct Infusion

5

25

50

75

100

125

ºC150

Time

Hot FillIing /Spray Drying

Filling

Cold Filling

Instan

t ESL UHT

F I G. 13.3: AP V STEAM I N F U S I O N STE R I L I S E R

F I G. 13.2: T I M E /TE M P E RATU R E P R O F I LE S FO R VAR I O U S I N F U S I O N

BAS E D P R O C E S S E S

F I G. 13.1: F LOW D IAG RAM FO R STEAM I N F U S I O N STE R I L I S E R

Page 22: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

22 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

H IG H H EAT I N FUS ION STE R I LI S E R

The growing incidents of heat resistant spores (HRS) are

challenging traditional UHT technologies and setting new targets.

The HRS are extremely heat resistant and require a minimum of

145 to150°C for 3 to 10 seconds to achieve commercial sterility.

If the temperature is increased to this level in a traditional indirect

UHT plant it would have an adverse effect on the product quality

and the overall running time of the plant. Furthermore it would

result in higher product losses during start and stop and more

frequent CIP cycles would have to be applied. Using the traditional

direct steam infusion system would result in higher energy

consumption and increased capital cost. On this basis SPX Flow

Technology developed the new High Heat Infusion system.

In Fig. 14.1 a flow diagram illustrates the principle design

including the most important processing parameters while

Fig. 14.2 shows the temperature/time profile in comparison to

conventional infusion and indirect systems.

Note that the vacuum chamber has been installed prior to the

infusion chamber. This design facilitates improvement in energy

recovery and it is possible to achieve 75% regeneration compared

to 40% with conventional infusion systems and 80 to 85% with

indirect tubular systems.

Fig. 14.3 shows a design of a High Heat Infusion system delivered

as a combi-plant consisting of an APV Tubular Steriliser with the

infuser module added on.

Advantages

• Micro-biological product safety by elimination of HRS spores

• Very long operating time between CIP

• Reduced contamination risk having vacuum chamber on non-aseptic side

• No flavour losses

• Add-on solutions and combi-systems

Limitations

• Capital investment costs

• Requirement for culinary steam

Products

• Milk and milk products

• Desserts

• Other products with conventional infusion systems

UHT of products with HRS (comparative temperature profiles with Fo= 40)

0

50

100

150

Time

ºC

Direct UHT 150ºCHigh Heat Infusion 150ºCIndirect UHT 147ºCReference Indirect UHT 140ºC

PRODUCT

FILLING

64

9

VACUUM

COOLINGWATER

5

STEAM

711 7

5ºC 60ºC

2

90ºC 125ºC

2

810 8

150ºC 75ºC 25ºC

STEAMSTEAM

1. Tubular preheaters2. Holding tube3. Flash vessel (non aseptic)

4.5. Steam infusion chamber6.

Non aseptic flavour dosing (option)

Homogeniser (aseptic)

7.8.9.10.

Tubular coolersTubular HeatersAseptic tankNon aseptic cooler

COOLINGWATER

3

F I G.14.3: AP V H I G H H EAT I N F U S I O N STE R I L I S E R

F I G. 14.1: F LOW D IAG RAM FO R H I G H H EAT I N F U S I O N STE R I L I S E R

F I G. 14.2: T I M E /TE M P E RATU R E P R O F I LE S I LLU STRATI N G H I G H H EAT

I N F U S I O N P R O C E S S I N G PARAM ETE R S

Page 23: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

23 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

I N STANT I N FUS ION PASTE U R I S E R

The infusion heating principle has increasingly been used for

high viscous and sticky products. However, some products have

been found to be very difficult or nearly impossible to handle

unless very short run-times were accepted.

This challenge led SPX Flow Technology to develop the

patented Instant Infusion system. The objective was to

design a system where a high kill rate can be achieved using

high pasteurisation temperatures and very low holding time

(<0.5 second) for products like egg white and whey protein

concentrate.

The patented design principle for the Instant Infusion Pasteuriser

is based on the conventional infusion system.

In order to have an efficient removal of the viscous and sticky

product from the infusion chamber, a positive displacement pump

has been placed in the outlet tube from the bottom cone very

close to the actual cone.

This effectively prevents any type of build-up of product at the

bottom of the infusion chamber and it has been possible to

increase the number of operating hours between CIP cleanings

from a few to more than 20 hours for some products.

In Fig 15.1 is shown the design of the infusion chamber with the

pump arrangement.

Fig. 15.2 shows an industrial installation of an Instant Infusion

plant.

Advantages

• Can handle high fouling products with long running time (>20 hours)

• High degree of flexibility

• Reduced chemical changes in comparison to conventional infusion

• Very high product quality

Products

• Whey protein concentrate

• Egg-based products

• Baby food

• Processed cheese

F I G. 15.2: AP V I N STANT I N F U S I O N PASTE U R I S E R

F I G. 15.1: I N STANT I N F U S I O N C HAM B E R

Page 24: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

24 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

STEAM I NJ ECTION STE R I LI S E R

This system operates by direct injection of steam into the product

through a specially designed nozzle as previously described (Fig.

8.4).

The heating is followed by flash cooling and final cooling, which

take place in either plate heat exchangers or tubular heat

exchangers.

The system is in its basic design quite similar to an infusion

system where the infuser has been replaced with an injection

nozzle. (Fig. 16.1)

Long operating times are possible because only a very small area

in the nozzle is subject to fouling.

The operating economy has been optimised through optimisation

of plant design, processing parameters and careful process

control.

The injection system handles low to medium viscosity products, in

the capacity range from 2,000 to 25,000 l/hour.

Fig. 16.2 shows an APV Steam Injection Steriliser.

Advantages

• Good product quality

• Long production runs

• Handles heat-sensitive products

Limitations

• Higher capital costs than for indirect systems

• Higher operating costs due to lower heat regeneration

• Mostly used for low viscosity products

• Requirement for culinary steam

Products

• Milk, flavoured milk, cream

• Soy milk

• Ice cream mix

PRODUCT

6 6

143ºC 75ºC 25ºC <25ºC

FILLING

5

7

VACUUM5ºC

STEAM

1. Plate preheaters2. Steam injection nozzle3. Holding tube

4. Flash vessel5. Aseptic homogeniser6. Plate coolers

7. Aseptic tank8. Non aseptic cooler9. Condenser

2

STEAM

75ºC

COOLING

COOLING

WATER

WATER

4

9

3

1

8 COOLINGWATER

Steam

Product

F I G. 16.1: F LOW D IAG RAM FO R STEAM I NJ E CTI O N STE R I L I S E R

F I G. 16.2: AP V STEAM I NJ E CTI O N STE R I L I S E R

Page 25: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

25 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

SCRAPE D SU R FACE H EAT EXCHANG E R

STE R I LI S E R

Scraped surface heat exchangers (SSHE) are the most suitable

equipment for treatment of high viscosity food products and

food products containing larger particles.

In a typical aseptic plant the product is pumped by a rotary

lobe pump or similar to feed one or more heating cylinders

followed by a holding tube and one or more cooling cylinders.

Capacities up to approximately 10,000 l/hour are available but

this depends to a large extent on the physical characteristics of

individual products.

Since the nature of the products can vary considerably in terms

of viscosity, stickiness or size and fragility of the particles, each

system is individually engineered to suit a particular product.

Even though systems based on SSHE are relatively expensive,

both in terms of investment and energy consumption, they are

still very competitive compared with batch sterilising systems.

Fig. 17 shows an SSHE based steriliser equipped with VT 4“

cylinders.

Advantages

• Handles high-viscosity products

• Handles sticky products

• Handles particulates up to approximately 13 mm

• Handles heavy-fouling products

Limitations

• Relatively high capital cost

• Relatively high energy requirements

• Higher maintenance costs owing to scraper blades, bearings and seals

• High spare parts requirement

• Limitation in respect of size of particulates

Products

• Milk concentrate

• Yogurt

• Processed cheese

• Whey protein concentrate

• Quark products

• Baby food

• Compotes

• Puddings, dips

• Sauces, soups

PI LOT U HT PLANT

The constant pressure on manufacturers to produce quality

products at the lowest possible cost creates a need for

evaluating the most suitable process system and optimising

processing parameters. Using production plants for tests on new

products and processes is both uneconomical and difficult.

Therefore SPX Flow Technology has developed a new

generation of pilot plants, which gives manufacturers the

possibility of performing tests on a small scale with easy

operation, flexibility and scaling up accuracy.

The continuous UHT pilot plant Fig. 18 has a capacity of 60 to

200 l/h and is designed for indirect tubular and direct steam

infusion heating.

F I G. 17: AP V S S H E STE R I L I S E R

F I G. 18: AP V U HT P I LOT P LANT.

Page 26: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

26 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

However, the following options can be included in the standard

system:

• High Heat Infusion

• ndirect Plate

• Direct Steam Injection

• Pasteurisation

• Deaeration/Deodorisation

• Scraped Surface Heat Exchanger

• and/or any combinations.

It is also possible to provide variable temperature and holding

time profiles. This makes the pilot plant extremely versatile. The

plant can be supplied with a 500 litre sterile tank, which will form

a link between the pilot plant and a filling machine.

Many manufacturers choose to invest in their own pilot plant

for in-house testing and product evaluation, but in other cases

they may choose to use one of SPX Flow Technology’s test and

development centres.

STE R I LE TAN K

It is not always practically possible to feed a sterile product

directly from the processing plant to the filling machine.

This is where the aseptic tank comes in as a buffer between

processing and filling units.

Besides serving as a buffer and storage tank for the sterilised

product the aseptic tank also adds an important degree of

flexibility to the production process as it provides for:

• Continuation of production regardless of interruption in filling rate. Usually one UHT line is connected to several filling machines with variable capacity. If the filling rate is not at a maximum, the UHT plants need to have a variable capacity or the product must be recirculated if allowed by local regulations.

• Continuation of filling during intermediate CIP or interruption in UHT operations. Many UHT plants need intermediate CIP after 8 to12 hours of operation, depending on the UHT system, product quality and type of product to be processed. The aseptic tank ensures that this process can be performed without interrupting the operation of the filling lines.

• Reduced investment. As the filling machines are the most expensive part of an aseptic processing line, it is important that they are utilised to their full capacity. To this end the aseptic tank is installed. By increasing the operating time of the fillers, a small increase in the capacity of the UHT plant creates the possibility of lengthening the production run significantly.

The aseptic tank is equipped with steam-shielded aseptic valve

clusters and supplied with sterile air at constant pressure. This

provides for a perfect balance between supply and demand from

the aseptic tank.

The aseptic tank is also fully automated, using programmable

logic controllers (PLC), and the control system can be

connected either to the UHT control system or to one of the

filling machines.

Fig. 19 shows the APV Sterile Tank.

F I G. 19: AP V STE R I LE TAN K

Page 27: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

27 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

D EAE RATOR

Deaeration is essential for production of high quality products.

While the products in the infusion systems are deaerated in

the infusion chamber this is not the case when indirect heating

systems are used.

In these cases the dearation can be solved through the

installation of the APV Parasol Deaerator, designed to remove

dissolved or entrained air under vacuum. The product is sprayed

into a vessel as a thin film in a parasol form, maximising product

surface area and deaeration efficiency.

The APV WI+ centrifugal pump is used to ensure pumping of

high viscous products under vacuum. The APV WI+ pump is

equipped with an APV - Universal inducer acting as a helical

screw pump mounted to the pump shaft in front of the impeller,

which reduces the risk of cavitation especially when pumping

high viscous products. The air content can be reduced to as low

as 0.5 ppm oxygen.

The APV Parasol Deaerator is shown in Fig. 20

Extended shelf life/ESLIn many parts of the world the production of fresh milk presents

a problem in regard to keeping quality. This is due to inadequate

cold chains, poor raw material and/or insufficient process and

filling technology. Until recently, the only solution has been to

produce UHT milk with a shelf life of 3 to 6 months at ambient

temperature. In order to try to improve the shelf life of ordinary

pasteurised milk, various attempts have been made to increase

pasteurisation temperature and this led to the extended shelf

life concept as referred to earlier in this publication.

SPX Flow Technology has in cooperation with Elopak developed

the Pure-LacTM concept, which in a systematic way attacks the

challenge of improving milk quality for the consumer.

THE PURE-LACTM PROCE SS

Based on investigations of consumer requirements and the present market conditions in a large number of countries the objective of Pure-LacTM was defined as follows:

• A sensory quality equal to or better than pasteurised products

• A “real life” distribution temperature of neither 5°C, nor 7°C but 10°C

• A prolonged shelf life corresponding to 14 to 45 days at 10°C depending on filling methods and raw milk quality

• A method to accommodate changes in purchasing patterns of the consumer

• An improved method for distribution of niche products

• To cover the complete milk product range, i.e. milk, creams, desserts, ice cream mix, etc.

• To provide tailored packaging concepts designed to give maximum protection using minimum but adequate packaging solutions

Having reviewed the range of “cold technologies” available it

became obvious that most of them were only suited for white

milk. Furthermore the actual microbiological reduction rate for

some of the processes were inadequate to provide sufficient

safety for shelf life of more than 14 days at 10°C.

Table 3 is a comparison between various processes and their

ability to reduce bacteria and various types of spores. Using the

data in Table 3 on a milk containing 10 to 100 spores/ml in the

raw milk out of which 10 percent are psychrotrophic spores, the

following result is achieved:

F I G. 20: AP V PARAS O L D EAE RATO R

D ECI MAL R E D UCTION OF VAR IOUS BACTE R IA AN D S POR E S

TYPE CE NTR I-FUGATION

M ICRO- FI LTRATION PU R E-LACTM

TOTAL BACTE R IA 1 2.5 10

AE R O B I C S P O R E S 1.3 2.4 6

AE R O B I C P SYC H R O-TR O P H I C S P O R E S

<1 2.4 8

AE R O B I C S P O R E S 1.7 4

TAB LE 3: C O M PAR I S O N O F VAR I O U S M ETH O D S FO R R E D U C I N G TH E

N U M B E R O F BACTE R IA AN D S P O R E S I N L I Q U I D M I LK

Page 28: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

28 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

• Microfiltration, log 3 reduction

1 to 10 psychrotrophic spores per litre in the final product

Every carton is a potential risk

• Pure-LacTM, log 8 reduction

< 1 psychrotrophic spore per 10.000 litre in the final product

Large safety margin and excellent quality buffer

Bacteria-removing centrifuges are also used to improve the

quality of drinking milk. As shown in Table 3 the decimal

reduction of bacteria and spores is less efficient than for

microfiltration. By reducing the throughput to half of the nominal

capacity or by double centrifugation the reduction is improved

by at least one decimal, which brings it closer to microfiltration.

However, double centrifugation increases the investment and

operating costs considerably, and this combined with the loss of

milk in the bacterial concentrate in the order of 1 to 6% reduces

the attractiveness of using bacteria removing centrifuges to

extend the shelf life of milk.

The basis for the process is the infusion technology as

described. Several years of research and development have

resulted in a technology, which provides an extremely gentle

heating to a temperature of 130 to145°C in less than 1 second.

The rate of heating is very fast in the order of 500 to 600°C/s

providing all the benefits previously described.

With a combination of this process technology, the appropriate

filling technology and a suitable carton it is possible to produce

and guarantee products with as good a taste and flavour as

pasteurised milk, having a shelf life up to 45 days at a storage

temperature of 10°C. For comparison the same milk pasteurised

at 72°C would have a shelf life of 1 to 2 days under the same

storage conditions, while it would keep fresh for 10 days at a

storage temperature of 4°C.

Comparison between different systemsAs illustrated in the presentation of the various technologies

there is a wide choice and there are several considerations to be

made before the final decision is taken. SPX Flow Technology’s

team of experts is available to advise on selecting the most

appropriate technology for each specific requirement.

Table 4 provides a rough guideline of the advantages and

disadvantages of different technologies in relation to a variety of

products. This is meant as a guideline to make the right choice,

which in many cases may be obvious while in other cases

more difficult. As mentioned in the section on the APV Pilot

Plant this provides a tool for testing different products using

different heating technologies, and this may sometimes become

necessary to ensure the correct choice.

Process controlsOne of the most important aspects of an aseptic plant is the

process control system. It must continuously monitor all process

parameters and take reliable corrective action in case of a failure.

Today all of SPX Flow Technology’s UHT systems operate under

a PLC (Programmable Logic Controller) or a DCS (Distributed

Control System) based on the world leading brands, providing

the best possible repeatability and reliability in the operation.

This means consistent product quality, package after package,

day after day. Human error is minimised and greater production

efficiency is achieved.

There are many systems, which are capable of successfully

operating an aseptic plant. However, when it comes to choosing

the right concept for the process control system there are

additional factors to take into consideration. Such factors include

hardware durability and availability, service from the supplier

and communication ability with surrounding control systems in

the plant. The operating personnel’s familiarity with a particular

control system is also important, and there may be special

regulatory codes, which require adaptation of control systems.

The world leading process technology - a result of many years’

development and experience - is built into our software packages.

The control system has already been tested in many similar

applications and they are always pretested prior to delivery.

Fig. 21 shows an SPX Flow Technology production management

system: The APV Factorty Expert Concept.

Page 29: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

29 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

LOR E M I PSOM PLATE STE R I LI S E R

TU B U LAR STE R I LI S E R

STEAM I N FUS ION

STE R I LI S E R

STEAM I NJ ECTION

STE R I LI S E R

H IG H H EAT I N FUS ION

STE R I LI S E R

I N STANT I N FUS ION PASTE U R-

I S E R

SS H E STE R I LI S E R

M I LK

LOW C O ST 1 2 5 4 3 5 5

H I G H Q UALITY 3 3 1 2 2 1 5

P O O R Q UALITY 4 2 1 2 2 1 5

H EAT R E S I STANT S P O R E S 3 3 2 2 1 5 5

F LAVO U R E D M I LK

FO U LI N G P R O D U CT (C H O C O LATE) 3 2 1 2 2 1 5

VO LATI LE AR O MA 1 1 3 3 2 3 5

D I F F I C U LT TO STE R I L I S E (C O C OA) 3 2 1 1 1 3 5

S E N S IT IVE C O LO U R 3 3 1 2 2 1 5

C R EAM

WH I P P I N G C R EAM 3 3 1 2 2 1 5

STAB I L I S E D D E S S E RTS 4 3 1 2 2 1 5

C O O K E D C R EAM 2 2 1 2 2 4 5

C O F F E E WH ITE N E R S

M I LK-BAS E D 1 1 2 3 1 3 5

VEGETABLE OIL-BASED (EMULSIFIED) 1 1 2 3 1 3 5

FO U LI N G / H I G H P R OTE I N C O NTE NT AN D STAB I L I S E R 4 4 2 3 4 1 5

J U I C E

W ITH P U LP, F I B R E S >1 M M 5 1 5 5 5 5 5

W ITH P U LP, F I B R E S <1 M M 3 1 5 5 5 5 5

W ITH O UT P U LP AN D F I B R E S 1 1 5 5 5 5 5

YO G H U RT 1 1 4 4 4 4 4

Q UAR K 5 5 4 4 5 3 1

BABY FO O D 3 3 1 2 3 1 1

M I LK C O N C E NTRATE 4 4 2 3 4 1 2

P U D D I N G S

STAB I L I S E D, H I G H S O LI D S, STAR C H 5 4 2 4 4 1 3

STAB I L I S E D W ITH CAR RAG E E NAN 3 3 2 3 3 2 3

S OY M I LK

LOW C O ST 1 2 5 4 5 5 5

H I G H Q UALITY 3 3 1 2 1 1 5

P O O R Q UALITY RAW MATE R IAL 4 3 1 2 2 1 5

C O F F E E AN D TEA 1 1 4 4 4 4 5

S O U P S AN D SAU C E S 5 2 4 4 5 5 1

OTH E R C O N S I D E RATI O N S

H EAT STAB I L ITY 3 3 1 2 3 1 3

AS E PTI C P R O D U CT 1 1 1 1 1 4 1

F LE X I B I L ITY 3 3 1 2 1 1 1

MAI NTE NAN C E 2 1 2 2 2 2 3

1 = E XC E LLE NT 2 = G O O D 3 = AC C E PTAB LE 4 = P O S S I B LE 5 = N OT R E C O M M E N D E D

TAB LE 4: C O M PAR I S O N B ETW E E N TH E M O ST C O M M O N LY U S E D P R O C E S S I N G SYSTE M S RATE D O N A S CALE F R O M 1 TO 5:

Page 30: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

30 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

Filling and packagingIn order to preserve their high micro-biological quality, aseptically

processed products must be packed aseptically. Even at room

temperature, the packaged product then has a shelf life of

several months.

In aseptic filling and packaging, the aseptically processed

product is filled under aseptic conditions into commercially sterile

containers, which are either preformed or formed in conjunction

with the filling operation. After the filling has been completed,

the containers are hermetically sealed. The resultant packages

are liquid-proof and exclude air, light and bacteria. This method

of processing and packaging allows for the use of paperboard,

plastic containers or pouches as packaging materials, and

eliminates the need for cans and energy inefficient retort heating

systems.

The choice of packaging concept depends on product type, unit

cost and customer preference. Environmental concerns, volume

of waste and the possibility of recycling of packaging material

become increasingly important depending however, on the stage

of development of the community.

SPX Flow Technology is not a manufacturer of packaging

systems but co-operates with all companies in the packaging

sector and is able to supply the appropriate solution for

complete and turnkey systems.

With an SPX Flow Technology system, customers are assured of a

complete aseptic processing line producing high quality products

packed for the specific market in the most cost-effective way.

Product developmentNew products are developed more rapidly than ever before in

order to satisfy demands in the consumer market. Simultaneously

the life-cycle of the individual products tends to shorten. These

conditions force the producers to intensify and accelerate

product development. Capabilities in aseptic processing and

related disciplines enable SPX Flow Technology to support

customers to develop new value added products at the highest

possible speed.

This can be achieved through product testing in the SPX Flow

Technology test and development centres around the world or by

means of an APV Pilot Plant installed at the customers site.

SPX Flow Technology is keen to work in partnership with

customers in order to accelerate the product development

process.

It is the objective of SPX Flow Technology to deliver innovation,

quality and reliability to the dairy, food and beverage industry and

in this way contribute to safe and high quality products for the

consumer.

Page 31: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

31 22000-06-01-2013-G B

Long Life Dairy, Food and Beverage Products

F I G. 21: AP V FACTO RY E X P E RT

Page 32: Long Life Dairy, Food and Beverage Products - SPX · PDF fileEnzymes 6 Moulds 7 Yeast 7 ... in Denmark offers Pilot Plant Testing and application ... Introduction to long life dairy,

S PX FLOW TECH NOLOGY

Pasteursvej

DK-8600 Silkeborg, Denmark

Phone: +45 70 278 278

Fax: +45 70 278 330

SPX reserves the right to incorporate our latest design and material changes without notice or obligation.

Design features, materials of construction and dimensional data, as described in this bulletin, are provided for your information only and should not be relied upon unless

confirmed in writing. Please contact your local sales representative for product availability in your region. For more information visit www.spx.com.

The green “>” is a trademark of SPX Corporation, Inc..

ISSUED 01/2013 22000-06-01-2013-GB

COPYRIGHT © 2010 SPX Corporation

ABOUT S PX

Based in Charlotte, North Carolina, SPX Corporation (NYSE: SPW) is a global Fortune 500 multi-industry manufacturing leader.

For more information, please visit www.spx.com.