Production Quality Issue Flashcards
How does stress affect color?
Decreases glycogen, which increases pH, which increases WHC, water is retained in the meat, and the meat looks darker.
What causes dark cutting beef/lamb?
long term or intermediate glycogen depletion
What are animal symptoms associated with long term stress?
exhaustion, excitement, sudden feed withdrawal, sickness
What happens physiologically in the muscle during long term stress?
There is limited lactic acid production so less pH decline postmortem
There is higher WHC, dark color, firmer meat, less free water (dry meat), microbial growth, and intense flavor
How do you prevent dark cutting beef/lamb?
- use proper handling and prevent stress
- add a 3-4 day rest to replenish glycogen stores
What causes DFD pork?
- Extended transport-hauling of pigs without feeding
- limited lactic acid production postmortem
How do prevent DFD pork?
Feed and rest for 24-48 hours before slaughter
What causes short-term stress?
very rapid glycolysis due to
1. excitement from handling or transportation
2. not chilling immediately postmortem
How do you prevent short-term stress?
- Genetic selection
- Rest to calm them down and restore glycogen reserves
- Improve animal facilities
- Improve handling
- CO2 stunning
What is PSS?
Porcine stress syndrome- a genetic abnormality where the animal is intolerant to stress, exhibits accelerated muscle metabolism, and produces more heat
Causes muscle twitching and red skin blothces
What genes cause PSS?
- Halothane (HAL) gene
- Rendement Napole (RN-) gene
Why were HAL genes in pigs popular in the 1990s?
They produced lean/heavily muscled hogs
Why do pigs with HAL genes have an abnormally fast rate of pH fall?
due to high pre-rigor temps and rapid glycolysis
How does RN gene cause PSE meat?
pig has greater amounts of glycogen which is used to generate more lactate, which causes the meat to have an extremely low pH (affects WHC and processing yield)
What does PSE stand for?
Pale, Soft, Exudative
What does RFN stand for?
Red, Firm, Non-exudative
What does DFD stand for?
Dark, Firm, Dry
(sticky surface)
What does RSE stand for?
Red, Soft, Exudative
What is RSE meat?
It is meat that is between PSE and normal. It is NOT pale but may lack a uniform cured color.
It has (some) pH decline, a lower WHC, and a (5-10%) lower processing yield
