PRESERVATION TECHNOLOGIES FOR FRESH FRUITS AND VEGETABLES: COLD STORAGE, MODIFIED ATMOSPHERE PACKAGING AND CONTROL ATMOSPHERE STORAGE 1 ST WORKSHOP January, 2002 Istanbul, Turkey Financial support by the Commission of the European Union under MEDA programme is acknowledged (Thematic Network ICA3-C5-2000-30004) Profª. Mª TERESA SANCHEZ
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PRESERVATION TECHNOLOGIES FOR FRESH FRUITS AND VEGETABLES: COLD STORAGE, MODIFIED ATMOSPHERE PACKAGING AND CONTROL ATMOSPHERE STORAGE 1 ST WORKSHOP January,
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PRESERVATION TECHNOLOGIES FOR FRESH FRUITS AND VEGETABLES:
COLD STORAGE, MODIFIED ATMOSPHERE PACKAGING AND
CONTROL ATMOSPHERE STORAGE
1ST WORKSHOP
January, 2002
Istanbul, Turkey
Financial support by the Commission of the European Union under MEDA programme is acknowledged (Thematic Network ICA3-C5-2000-30004)
Profª. Mª TERESA SANCHEZ
SPANISH FRUITS AND VEGETABLES:
PRODUCTION, IMPORTATIONS and EXPORTATIONS
FOOD CONSUMPTION
FOOD CONSUMPTION IN THE E.U.
MEDITERRANEAN COUNTRIES
PERISHABILITY AND PRODUCE LOSES
Have accurate control of temperature.
Reduce microbial loading.
Control and/or modify the packaging atmosphere. Deter enzymatic browning.
Maintain all of the above while offering a consistent, predictable quality level for all deliveries.
THE EMPHASIS OF ANY FRUIT AND
VEGETABLE PROGRAM IS TO:
COLD STORAGE OF FRUITS AND VEGETABLESCOLD STORAGE OF FRUITS AND VEGETABLES
COLD CHAIN
REFRIGERATED TRANSPORT
COOLING PROCESS
1. Reducing respiration and degradation by enzymes.
2. Reducing water loss and wilting.
3. Slowing the growth of decay organisms.
4. Reducing the production of ethylene, the natural ripening agent.
5. Providing time for proper handling and processing.
The most effective way to maintain quality and safety of fresh fruits and vegetables and their products is to maintain the COLD CHAIN, including the optimum range of relative humidity, throughout the postharvest life of the commodity.
MAXIMIZE THE SELF-LIFEMAXIMIZE THE SELF-LIFE MINIMIZE SHRINKAGEMINIMIZE SHRINKAGE
REFRIGERATED TRANSPORT
TEMPERATURE
CONTROLLED TRANSPORT
PROBLEMATICS OF FOOD PRESERVATION BY
REFRIGERATION
PROBLEMATICS OF FOOD PRESERVATION BY
REFRIGERATION
Requires continuous expense.
The cold chain (production, transport, store, consumption) should not be broken. Problems of interruption of cooling machine power and/or shortage of cooling agent (ice, eutectic mixtures).
Reduce enzymatic activity but do not kill, implies T<6 ºC for a few days but T<-18 ºC for a few months.
Cooling increases relative humidity and increases surface fungi.
Packed enclosure prevents it, but it asphyxiates vegetables. (Ambient humidity not relevant for frozen food.)
In mixed spaces some food give odours (potatoes) and others take (dairy). Some stores require ventilation for fresh air or air treatment for controlled atmosphere.
CONTROLLED ATMOSPHERE STORAGE OF SELECTED
FRUITS AND VEGETABLES
CO2 and O2 concentration
Relative HumidityTemperature
CONTROLLED ATMOSPHERE STORAGE
• Presence and quantity of:• CO2
• O2
• Ethylene• Products in optimum conditions:
• Type• Variety• Origin• Climatic background
• PRODUCTS:• Life can be extended by 30%• Losses and diseases are reduced by 30-80 %
Maximum concentration of CO2 and minimum concentration of O2 in AC storage
Kader, 1980
CA MANIPULATIONS
• Initial low oxygen stress treatment (ILOS).
• High CO2 shock treatments.
• A range of O2/CO2 concentrations.
• CA combined with other treatments as a possible replacement for SO2.
Lower values of O2 and CO2
Better gas-tight insulation techniques
Computer control systems
MODIFIED ATMOSPHERE PACKAGING OF SELECTED FRUITS AND VEGETABLES
PUTTING THE PRODUCT TO SLEEP
Produce generate their own atmosphere in plastic bags
•Cultivar or genotype•Production area•Harvest maturity•Other factors
The potential positive and negative effects MAP has on the Food Industry
Davies et al., 1995
MODIFIED ATMOSPHERE
• Produced naturally by respiration
PASSIVE M.A.The permeability characteristics of the film determine the equilibrium gas concentration achieved in the package.
• Produced by the application of gas flushing techniques
EQUILIBRIUM M.A.The actual equilibrium MA attained within a package will also depend on factors such as the prepared form of the vegetable studied, the rate of respiration at storage temperature, the pack volume and fill-weight, and the surface areas for gas exchange.
GENERAL EFFECTS OF MAP ON MICRO-ORGANISMS
Not well studied.
Gram negative bacteria (Pseudomonas) more sensitive to CO2 than Gram positive.
CO2 at sufficient concentration can inhibit the growth of spoilage moulds.
FACTORS TO CONTROL INMAP
• FOOD HYGIENE
• TEMPERATURE CONTROL
• STOCK ROTATION
• QUALITY ASSURANCE TESTS
• MICROBIOLOGICAL TESTING
• SEAL INTEGRITY
• GAS ANALYSIS
• TEMPERATURE MONITORING
FUTURE OF MAP
1 OPTIMISING MAP OF A VARIETY OF
FRESH PRODUCTS UNDER VARIOUS
STORAGE CONDITIONS.
2 TESTING MAP FILMS FOR CLIENTS.
3 EVALUATING EDIBLE COATINGS.
FOCUS AREAS OF FOCUS AREAS OF MAP RESEARCH:MAP RESEARCH:
ENVIRONMENTAL IMPACT OF PRESERVATION TECHNIQUES OF
FRUITS AND VEGETABLES
• CFC’s, the predominant refrigerants used in reefer containers.
• Proposed restrictions on HFC’s become a reality, refrigerated transportation will face serious challenges in finding acceptable substitutes.
QUALITY AND CONSUMER ACCEPTANCE
• High quality fruits and vegetables are one of today's wonders with regard to Spanish food supply.
• Unfortunately, many Spanish fruit and vegetable growers believe that once a high quality product is produced, their problems are over. In reality, their troubles could be just beginning. It has been estimated that more than 40 % of perishable commodities are lost after production.
• Price received for produce is determined by quality at the marketplace.
Direct contact between the seller and the consumer results in the consumer being able to select the particular items and enabling the seller to react quickly in response to consumer demands. This ensures a high level of consumer satisfaction.
Variables consumers perceive as a reflection of produced quality:Variables consumers perceive as a reflection of produced quality:
Producers who are able to produce and package their produce in such a way to enhance these variables are the most successful in the market place.
• Texture: Crispness and freshness.
• Flavor and taste.
• Nutritive value.
• Price.
• (1) The quality inspection procedures that must be carried out (Commission
Regulation 2251/92 of 29 July 1992),
• (2) What quality they must have (Common Quality Standards' that have been promulgated throughout the years), and
• (3) The maximum limits of pesticide residues admitted and how they should be controlled (Council Directive 76/895/EEC, 90/642/EEC and 93/58/EEC).
• Within the Regulation applied to foodstuffs, fruit and vegetables must fulfill the provisions on labels (Council Directive 79/112/EEC and the one that regulates the quantity of products in the packages (Council Directive 76/211/EEC).
How to assure the quality of a product? How to make commerce easier?
January, 2002
Istanbul, Turkey
Financial support by the Commission of the European Union under MEDA programme is acknowledged (Thematic Network ICA3-C5-2000-30004)
Profª Mª TERESA SANCHEZ
THANK YOU VERY MUCH
PRESERVATION TECHNOLOGIES FOR FRESH FRUITS AND VEGETABLES: COLD STORAGE, MODIFIED
ATMOSPHERE PACKAGING AND CONTROL ATMOSPHERE STORAGE