Practicals Flashcards
Define meat
The skeletal muscle and the closely attached edible tissues (fat, connective tissue, blood) of food producing animals or Every part of the animal’s body from which food can be produced
Organoleptic properties of meat
PIGS CRIBS Colour (scarlet red) pH Specific smell Glossy Inelastic Incomplete bleeding Interwoven w CT and fat Body condition Rot Stuffiness
Influences of organoleptic properties of meat
Maturation Species, breed, age, gender, body part Feed Slaughtering process
pH change in meat caused by
Glycogen (pH 7.6) b/d to Lactic Acid (pH 5.5)
Measuring pH
Nitrazine yellow Bromothymol blue Electric pH meter Indicator paper
Colour of myoglobin
Purple red
Colour of oxymyoglobin
scarlet red
Colou of methimoglobin
brown red
Colour of sulfmyoglobin
yellow
Colour of cholemyoglobin
green
Colour with high O2
oxymyoglobin
Colour with low O2
metmyoglobin
Colour with no O2
deoxymyoglobin
Yellow coloured meat caused by
– Lipochromatosis (Carotenoids +) – Lipofuscin-like pigments (Unsaturated fatty acids +) – Icterus / Jaundice: Pathological
Black coloured meat caused by
Melanin (lungs), porphyrins (ribs)
Yellow discolouration examination
Alcohol ether -Jaundice: BR dissolves in alcohol Carotenoids: dissolves both in ether
Test smell
Organoleptic judgement- boiling and roasting
Abnormal smell
• Alimentary (e.g. fishmeal, moldy feed) • Boar taint (androstenone, skatole) • Antemortem (disease, metabolic disorder – Lab examination) • Postmortem (acquired from the environment)
Incomplete bleeding results in
hemoglobin infiltration of the meat
Reasong for incomplete bleeding
– Slaughtering technology – Disorder of the circulatory / nervous system – Toxicosis – Infection – Stress
Determination of incomplete bleeding
Reder test (Löffler reagent – Methylene blue)
Rot: cause of it?
Bacterial decomposition of nitrogenous compounds
Rot effect on pH
increases it
Rot effect on protein
biogenic amines, indole, skatole, H2S, NH3, CO2
Rot effect on fat
volatile fatty acids, palmitic acid
Detection of rot
NH3 presence (Eber’s test, Nessler’s test)
Rot: microorganisms
PAM CAP Pseudomonas, Proteus, Achromobacter, Micrococcus, Alcaligenes spp. Anareobic: deep inside the large muscles Clostridium spp. > Gas production
Stuffiness
Enzimatic degradation of nitrogenous compounds Hydrogen-sulfide (H2S) production
Stuffiness effect on pH
Acidic / neutral pH
Detection of stuffiness
Lead acetate/Lead nitrate test
Consistency: compressibility
Grau & Hamm: filter paper press method
Tenderness, texture
– Sensory judgment – Enzymatic digestion – Warner-Bratzler shear force test
Liquid-holding capacity
• Proteins: actin, myosin, sarcoplasma proteins • Dissolvedsalts • pH
Liquid holding capacity: determination
– Grau & Hamm method: 0,3g meat + filter paper (5 mins) – Liquid leakage method: measuring drip loss – Drying method
Experiments: pH
indicator paper
Experiments: cooking test
Bunsen burner, pot
Experiments: Reder’s test
Loeffler reagent (methylene blue)
Experiments: Eber’s test
glass tube, NH3
Experiments: Nessler test
Nessler’s reagent, NH3
Experiments: Liquid holding capacity
Grau-Hamm
Experiments: Consistence
Grau-Hamm filter-paper press method
Reg. No. 852/2004/EC
hygiene of foodstuffs
853/2004/EC
hygiene rules for food of animal origin
854/2004/EC
official controls on products of animal origin intended for human consumption
Normal, routine slaughter
individual or group slaughter of healthy animals
Separate slaughter
suspected infection or disease; separated in terms of space and time
Emergency slaughter
urgent bleeding of any injured but healthy animal (e.g. after accident)
ANTE MORTEM I
Inspection of the animals in the farm
ANTE MORTEM II
Inspection of the animals in the slaughterhouse