Meat Science 1

nutrients in meat

zinc, iron, protein (ZIP) & vitamin b12

protein in meat is significant because …

1. high biological value where a high proportion of protein from meat is absorbed by the body to synthesize protein

2. easily-absorbed heme-iron

meat quality is determined by __ & __

nutritional quality & “eating” quality

how is fresh meat produced & processed from animals?

• pre-slaughtering; live animals brought to slaughter house, ante-mortem inspection is carried out

• slaughtering; animals are stunned (made unconscious) & sticked (bleeding)

• cutting & cleaning; skin & visceral organs are removed (evisceration)

• post-mortem inspection

• wholesale cuts > chilling > retail cuts

• freezing

• storing

what are the causes & effects of stress experienced by animals during pre-slaughter handling

• rough transport from farm to slaughter house w change in env, physical activity & fights

  • bruising of carcass → affects weight & yield

• food & water deprivation

  • glycogen depletion → affect meat quality (colour, tenderness)

• separation & mixing of animals from diff social grps → physiological distress

slaughtering of animals

stunned first, following by bleeding

• stunning: animals are immobolised to facilitate cutting of blood vessels

  • prevents animals feeling pain / distress

• sticking: major blood vessels in the neck or thorax are cut

  • animals bleed to death via exsanguination

2 considerations during slaughtering

1. drugs X used for animals intended for human consumption

2. during religious slaughtering, animals X stunned before they are killed by sticking & exsanguination

some methods of stunning

1. use of mechanical instrument

2. passing electrical current through the brain

3. anaesthesia (e.g co2)

the __ system accelerates the exsanguination process + [description]

overhead hail system

• hanging of animal by its hind legs

• more effective draining of blood from major blood vessels

• reduces cross-contamination & manpower

dressing of carcasses is to __ but it also __

prevent microbiological contamination → reduce risks from pathogens → prolong shelf life of meat

but it can also introduce mb contamination due to contact w equipment, hands & clothes of workers

process of dressing & cutting carcasses

• body parts like head, feet, hair, skin, excess fat are removed

• internal organs removed (evisceration)

• trimmed & split into 2 halves

• washed & cleaned

• chilled

• wholesale cuts

what happens after dressing & cutting

post-mortem inspection of the carcass & offal (internal organs) is done by vet

• check for disease / damage

• if have, condemned

after meat has been cut & checked, how & why are they processed

• meat; rich in proteins, lipids, water → favourable substrate for MOs growth

• lipids → prone to oxidation

processing methods:

• chilling / freezing

• cooking → destroy MOs & enzymes

• curing → reduce water content by binding water w salt or other substances (becomes unavail to MOs)

• use of chemicals → inhibit mb growth

• use of technologies [radiation]

primary cooling is done by __ & the specific conditions are …

done by hanging dry carcasses (on rails) in small cold rooms / cooling tunnels

• deep muscle temperature should reach 6-7 degrees

• RH ~90%

  • prevents drying → implications on mass n texture

• air speed ~0.5 m/s

  • ensures well-spread temp

lastly, when meat is transported, it should be __

refrigerated

meat should not be thawed & refroze beacuse __

it can lead to moisture loss (quality & texture) & promote the growth of harmful bacteria (safety) which could lead to spoilage & food poisoning