The meat we eat: from a Food Security perspective

The meat we eat: from a Food Security perspective

Louw HoffmanDepartment of Animal Sciences

[email protected]

Food Security

• According to the 1996 World Food Summit, “Food security exists when all people, at all times, have physical and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life.”

• Food security is multi-faceted, and solutions to the growing global demand for food will involve finding new ways to increase sustainable agricultural productivity as well as augment the nutritional value of food via crops and livestock.

• Our program focus on animal products: meat

Food Security at SU

Production activities

Fresh meat

Processed meat

Production activities

Fresh meat

Processed meat

Research Focus

sufficient, safe and nutritious food

sustainable agricultural productivity

nutritional value

Increase productionDecrease losses along value chain

Production activities

Fresh meat

Processed meat

Meat

Red

Traditionally Farmed species

Exotic meat

Poultry

Farmed

Wild fowl

Fish / aquaculture

Farmed

Wild

Crayfish / abalone

Research focus

Fresh meat

Processed meat

• shelf life stability• lipid oxidation• protein oxidation• colour stability• microbiological stability

• minimise losses

Meat quality and composition

GENERAL

Quality• colour• texture• juiciness• flavour

Chemical composition• proximate• fatty acid• amino acid• mineral• myoglobin• collagen

Sensory

• quality & composition• decrease costs• develop new products

STUDENT ACTIVITIES & RESEARCH PROJECTS

Meat

Red

Traditionally Farmed species

Exotic meat

Poultry

Farmed

Wild fowl

Fish / aquaculture

Farmed

Wild

Crayfish / abalone

Cattle• PhD: Dam size on productivity• MSc: shelf life mince• MSc: Informal abattoirs• Res: organ meat

Sheep• MSc: effect of feedlot vs. free range • MSc: Effect of breed on meat quality • MSc (x2): Nutrition & production• Res: Wet carcass syndrome• Res: organ meat

Pigs• MSc: Production of cheaper polony

Extensive production system (Free range)

– Traditional method

– Animals roam freely (unlimited exercise/grazing)

• South Africa: sheep & cattle farming – Cattle finished off in feedlots

MSc project: lambs housed on a 10 hectare plot

Intensive production system (Feedlot)

– Confined to barns (no/limited exercise)

• Australia (Sheep farming + 16%, 2008)

• Aspect currently developing in RSA

MSc project: lambs housed in 1 x 2m indoor pen from birth

Exercise

Fiber type Transition sequence

IIB IIA I Limited exercise

Unlimited exercise

Sample collection and preparation Abattoir• Samples were collected < 60 min post mortem•Samples – left side of the carcass• 5 mm x 5 mm superficial muscle tissue – scalpel blade• Mounted on cardboard square with Tissue Medium• Muscle fiber direction perpendicular to cardboard surface• Tissue mount soaked in iso-pentane• Snap frozen in liquid nitrogen (-159°C)

Muscle location•Longissimus dorsi - 9th rib, 50mm from midline

Laboratory• Stored at -80°C until analysis

Cryostat• Successive sectioned• 10 μm• -23°C• 60% relative humidity• Mounted on a glass slide (no cover slip)

Biceps femoris

Semimembranosus

Longissimus dorsi

25

26

27

28

29

30

31

32

33

34

50 55 60 65 70 75 80 85 90

Typ

e2

A

FIRSTBITE

Fiber Type & Sensory Tenderness Correlation between Fiber Type IIA & Tenderness (First Bite)

Figure 8 Positive Pearson’s correlations (r=0.505; p=0.002) for Type IIA fiber and first bite

Meat

Red

Traditionally Farmed species

Exotic meat

Poultry

Farmed

Wild fowl

Fish / aquaculture

Farmed

Wild

Crayfish / abalone

Game• PhD: Production potential in Namibia• PhD (x2): Supply chain of formal & informal game meat• PhD: Health & safety• MSc: Effect of harvesting on quality & losses• MSc (x4): Production & quality of various species• MSc: game meat products

Ostrich

Outcome from PhD in

Sustainable Game Meat

Production in Namibia

Game meat supply chainPrimary producers

(game farmers)

Abattoir Large scale

processor

Wholesaler

Retailer

Local

consumers

Supplie

rs o

f pro

cessin

g m

ate

rials

Hunting

(Including field slaughter) Exp

ort

Harvesting

(Including field slaughter)

Farm abattoir

Small scale

processorTra

nsp

ort

Imp

ort

Meat

Red

Traditionally Farmed species

Exotic meat

Poultry

Farmed

Wild fowl

Fish / aquaculture

Farmed

Wild

Crayfish / abalone

Game

Ostrich• PhD: Freezing & thawing losses• MSc (x2): Effect of lairage & bruising on quality & losses• MSc: Modelling on growth and meat yield• MSc (x2): Effect of nutrition, production & transport on quality• MSc: Effect of diet on nutritional composition

>10% Thaw Loss

?Thermodynamic principles of

Freezing and Thawing

Chemical composition of Ostrich Meat

Rate of Freezing – Ice Crystal Formation

No standard for Freezing or Thawing of Ostrich Meat

Rate of Thawing – Moisture uptake

Meat

Red

Traditionally Farmed species

Exotic meat

Poultry

Farmed

Wild fowl

Fish / aquaculture

Farmed

Wild

Crayfish / abalone

Chicken• MSc: Comparison of free range and intensive production on quality• MSc: Effect of diet on nutritional composition

Wild fowl• MSc: Composition of Egyptian geese• MSc: Composition of Guinea fowl

A Profile of South African Game Bird Meat

6 Treatments

Descriptive Sensory Analysis

– Trained panel - 8 Judges

– 14 Attributes

Instrumental analysis

Statistical analysis – 6 x 6 Design

– Univariate analysis

– Multivariate analysis

(AMSA, 1995; Honikel, 1998)

1. Egyptian Goose 4. Ostrich Fan Fillet2. Guinea Fowl 5. Ostrich Moon Steak3. Pekin Duck 6. Broiler Chicken

AROMAGame Aroma Chicken AromaOstrich AromaBeef Aroma

FLAVOURGame Flavour Chicken FlavourOstrich FlavourBeef FlavourMetallic Flavour

TEXTUREInitial JuicinessSustained JuicinessTendernessResidue

• Drip loss• Cooking loss• pH• Colour• Shear Force• WBC

DA PLOT - SENSORY

FUTURE RESEARCH

• Proximate Analysis• Fatty Acid Composition• Amino Acid Composition• Mineral Composition (Fe)

• Carcass Yield• pH Profiling• Colour• WBC• Drip loss• Cooking loss• Shear Force

•Univariate Analysis•Multivariate Analysis•Correlation Analysis

• Aroma • Flavour• Texture• Instrumental

Physical Analysis

Sensory Analysis

Statistical Analysis

Chemical Analysis

EGY

PTI

AN

GO

OSE

GRAIN SEASON

GENDER

PROFILING OF

SA GAME BIRD

MEAT• Sensory Analysis• Instrumental Analysis

• Chemical Analysis

• Proximate Analysis• Fatty Acid Profile• Haemoglobin• Myoglobin• Fe

Meat

Red

Traditionally Farmed species

Exotic meat

Poultry

Farmed

Wild fowl

Fish / aquaculture

Farmed

Wild

Crayfish / abalone

Fish• PhD: Quality of Snoek

• MSc: Chemical composition of yellowtail• MSc (x2): Comparison of quality of farmed vswild yellowtail• MSc: colour stability of tuna• MSc: Nutritional value of shark meat• MSc: Nutritional composition of snoek

The determination of the nutritional composition and sensory quality of Mustelus

mustelus meat for commercial use

Smoothhound shark (Mustelus mustelus) is one of the five commercial shark species caught in South Africa

o Cow shark

o Soupfin shark

o Blue shark

o Mako shark

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Nutritional CompositionCross Carcass Variation

5 anatomical sites

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Proximate Composition

A B C D E P value

Moisture % 76.39 77.64 76.65 76.46 76.87 0.2092

Protein % 23.82 22.68 23.82 24.13 23.59 0.1485

Fat % 1.21 1.15 1.09 1.09 1.12 0.5220

Ash % 1.18 1.35 1.17 1.20 1.12 0.3058

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Table 1. Preliminary results for cross carcass variation of proximate composition (n=5)

Yellowtail/Snoek

Meat

Red

Traditionally Farmed species

Exotic meat

Poultry

Farmed

Wild fowl

Fish / aquaculture

Farmed

Wild

Crayfish / abalone

Crayfish•PhD: Quantifying fatty acid metabolism in crayfish• MSc: Effect of production parameters on quality

Abalone• MSc: Effect of diet composition to minimise weight loss & quality• Res: Decrease in value due to blueing

BLUEING IN CANNED ABALONE

(HALIOTIS MIDAE)L.C. Hoffman & E.F. Uys

Department of Animal Sciences, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa

e-mail: [email protected]

South Africa farms and exports approximately 1000 tons of abalone of which approximately 50% is canned. Discolouring (blueing)

on the epipodium and top layer of the mantle area in canned abalone has been an ongoing problem for the industry.

The aim of this research is to identify the component(s) causing blue discolouration.

Twenty-four canned abalone samples were selected: 8 light blue abalone, 8 dark blue (substandard) and 8 with no discoloration

(white abalone). In a secondary trial, three samples of the epipodium from the light blue, dark blue and white groups were

selected. All the samples were analysed for proximate, anion and cation composition.

RESULTS & DISCUSSION

There were only slight differences in the moisture, protein and lipid contents of the various groups (Table 1). Mineral results

showed no difference in Zn levels, hence it can be deduced that Fe and Cu may be major contributing factors to discolouration in

the epipodium.

Table 1 Proximate composition of canned abalone (H. midae) showing discoloration (dark blue and light blue abalone), as well as abalone with no discoloration (white abalone).

Moist

(%)

Protein

(%)

Lipid

(%)

Fe

(mg/100g)

Cu

(mg/100g)

Zn

(mg/100g)

Dark blue abalone 75.5a ± 0.85 16.7a ± 0.74 3.6a ± 0.21 36.1a ± 2.69 4.2a ± 0.76 23.1a ± 0.44

Dark blue (epipodium) 80.6 12.7 4.3 5.2 0.9 2.2

Light blue abalone 75.4a ± 0.85 17.5a ± 0.73 3.5a ± 0.15 42.4a ± 2.80 3.6ab ± 0.48 28.4ab ± 2.19

Light blue (epipodium) 80.2 13.5 4.3 5.0 0.6 2.5

White abalone 74.3a ± 0.74 15.1a ± 0.52 3.5a ± 0.39 15.1b ± 1.60 1.7b ± 0.16 22.6b ± 1.59

White (epipodium) 78.7 12.7 4.2 1.4 0.2 1.9

Results from the elemental analysis (Table 2) showed that the ratio of the sulphates (SO42-) and phosphates (PO4

3-) (blue:normal)

were higher than expected in the affected abalone, and this strengthens the possibility of copper sulphate being responsible for the

discolouration. Another interesting phenomenon is that the chlorine levels are 3 times higher in the normal abalone.

CONCLUSION

Discolouration cannot be reversed once the product is completed therefore treatment of abalone prior to canning is important.

Several causes of discolouration have been suggested. Improper handling and transport of abalone can cause internal bleeding

resulting in a blue colour due to oxygenated hemocyanin.

Stressed and moribund animals are also prone to have more sulphides available, and interactions between copper and these

sulphides are also implicated in discolouration. These aspects warrant further research.

Cation analysis (mg/L)

Ca Mg Na K

Blue abalone 349.00 580.00 831.00 680.00

Normal abalone 701.50 1036.00 2403.00 528.00

Ratio of blue:normal 0.50 0.56 0.35 1.29

Anion analysis (mg/L)

CH2OO- Cl- PO43- SO4

2-

Blue abalone 3050 1536 2147 341

Normal abalone 5100 5300 1931 315

Ratio of blue:normal 0.6 0.29 1.11 1.08

Table 2 Cation and anion analysis (water extract) were done on normal and blue abalone. The ratio of blue:normal abalone is also calculated.

Figure 1 Canned abalone (H. midae) showing no discoloration (white abalone, left) as well as abalone with discoloration (dark blue and light blue abalone, right).

Community Interactions

Who are the partners?

• Stellenbosch– Animal Sciences– Food Sciences– Microbiology– Physiology– Engineering– Conservation, Ecology &

Entomology

• Local– Department of Agriculture (WC)– CPUT– TUT– UP– UWC– DAFF

• International– Padova University (Italy)– Louisiana State University (USA)– Carné Technologies (NZ)

Additional funders• Red Meat Development Trust

• NRF

• EU: COOPERLINK travel & research grant

• DAFF– Most contributions “in kind”

• Private Sector– Most contributions “in kind”

What has OSP funding changed?

• Directly

– Improved infrastructure

What has OSP funding changed?

• Directly

– Improved infrastructure

– Increased post graduate participation

• Bursaries

• Project funds

– Increased collaboration with new disciplines

• Indirectly

– Functions as a source of seeding money

The road ahead

• Continue research projects with Padova University

• Finalise research agreement with Reunion Island: tuna & heavy metals

• Find new international partners – Africa

– Europe

– Australasia

• New project with NRF

• New projects with RMRDT

• Attempt to leverage funds via THRIP