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Flashcards in FH II Lab 3 Deck (17)
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1

Define meat

• Def. 1.: „The skeletal muscle and the closely attached edible tissues (fat, connective tissue, blood) of food producing animals”

• Def. 2.: „Every part of the animal’s body from which food can be produced”

2

Organoleptic properties of meat

Colour, specific smell, glossy, inelastic

interwoven with CT and fat

Influenced by; maturation, species, breed, age, gender, body part, feed and slaughtering process

3

Organoleptic properties of meat 2

Smell, taste, pH, rot, Colour, body condition, incomplete bleeding, stuffiness

4

pH

glycogen @pH7.6 water + CO2

pH 5.5 lactic acid

5

How to measure pH

Nitrazine yellow
bromothymol blue
electronic pH meter
indicator paper

6

Colour, oXygen level of meat

high - oxymyoghobin (lightest)
low 1% - metmyoglobin
none - deoxymyoglobin (darkest)

7

Yellow discolouration

lipochromatosis (carotenoids) dissolves in ether
lipofuscin like pigments (Unsaturated FA)
Icterus, jaundice - pathological - bilirubin dissolves in alcohol

8

Black discoularation

Melanin, porphyrins
Fit / unfit for human consumption

eg. melanosis in the lungs , porphyria in ribs

9

Taste and smell

Organoleptic judgment, boiling and roasting
abnormal smell
- alimentary (fish meal, mouldy feed)
- boar taint ( andrstenone, skatole)
- antemortem (disease, metabolic disorder - lab exam)
- postmortem (acquired from the environment)

10

Body condition

Leaness: physiological
emanation, cachexia, pathological

Young age, runtiness

11

Incomplete bleeding

Hemoglobin infiltration of meat
reasons
- slaughtering technology
- disorder of the circulatory / nervous system
- Toxicosis
- infection
- stress

Determination with the Reder's test (Loffler reagent, methylene blue)

12

Rot

bacterial decomp of nitrogenous compounds
- ph increase
- protein --> biogenic amines, indole, skatole, H2S, NH3, CO2
- Fat - VFAs, Palmitic acid
- Detection: NH3 presence (Ebers test, Nessler test)

13

Types of rot

Aerobic
- starts from the surface
Psuedomnoas, proteus, achrombacter, micrococcus, alcaligenes

Anaerobic
- deep in side large muscles
- Clostridial infections --> gas production

14

Stuffiness

- enzymatic degradation of nitrogenous compounds
- acidic / neutral pH
- H2S production
- detection with lead acetate / lead nitrate test

15

Physical Characteristics of Meat

Consistency : compressibility
- grau and Hamm: filter press method

Tenderness , texture
- sensory judgement
- enzymatic digestion
- Warner bratzler shear force test

16

Liquid holding capacity

- Protiens: actin, myosin, sarcoplasma proteins
- dissolved salts
- pH
Determination
- Grau and Hamm, .3g of meat and filter paper, press fr 5 mins
- Liquid leakage: measuring drip loss
- drying method

17

Experiments

pH - indicator paper, electrical pH meter
Cooking test : Bunsen burner, pot
Reder;s Test; loffler reagent, (methylene blue) (haemoglobin infiltration of meat)
Ebers test: glass tube, NH3
Nessler reagent: NH3
Liquid holding capacity: Grau Hamm
Consistency: Grau Hamm filter paper pressmethod

Shear force test - Warner Bratzler