Sustainable Food Chain

Question 1

Illustrate the basic chemical reaction to convert muscle to meat

Answer 1

ATP (Adenosine Triphosphate) Depletion: After slaughter, the muscle cells no longer receive oxygen, leading to anaerobic metabolism. This results in the breakdown of glycogen into lactic acid and the depletion of ATP, which is crucial for muscle relaxation.

Lactic Acid Build-up: As ATP runs out, lactic acid builds up in the muscles. The pH of the muscle drops (becomes more acidic), which causes the muscle proteins (mainly actin and myosin) to change shape and bond more tightly, resulting in rigor mortis.

Proteolysis: Over time, the muscle undergoes proteolysis, where enzymes break down proteins in the muscle, leading to tenderization. The muscles become softer as the proteins degrade and the muscle fibers are broken down.

Question 2

What is conditioning of meat

Answer 2

Conditioning refers to the controlled holding of carcasses in a cool environment to allow rigor mortis to fully set and start the natural process of muscle breakdown.
Typically, the meat is kept at a temperature of around 0–4°C for 1–3 days (depending on the species). During this time, the muscle fibers relax and the enzymes naturally begin to break down the proteins, improving tenderness.

Question 3

What is dark firm dry meat (DFD)

Answer 3

Chronic stress more long-term
pH in 12-24h post-mortem is ≥6 (target pH 5.4-5.5)
Glycogen stores depleted PRIOR TO slaughter (Muscle tensing/relaxing)

Question 4

What is Pale,Soft, Exudative (PSE) meat

Answer 4

Acute stress more short-term (Electric goads, prolonged lairage time, fighting before stunning)

The pH of pale, soft, exudative (PSE) meat is typically less than 6 at 45 minutes after slaughter:

Question 5

Rapid chilling reduces microbial growth, evaporation and drip loss, but risks cold shortening (CS). What is cold shortening

Answer 5

Cold shortening occurs when calcium is retained and concentrated in the sarcoplasm, which induces muscle contraction resulting in toughness.

Question 6

How to prevent cold shortening

Answer 6

Beef and lamb: not below 10C in the first 10h
Pork: not below 10C in the first 3h

Question 7

What is hot boning

Answer 7

Method of deboning a meat carcass while the meat is still warm, before rigor mortis sets in

Question 8

What is Hip suspension and how does it increase tenderness

Answer 8

Bovine carcass suspended through obturator foramen, instead of conventional Achilles’ tendon.
Stretching improves tenderness of some of the more expensive muscles around rump