The amount of ferrihemochrome formation from myo- globin during cooking is affected by initial meat pH. While mammalian muscle has a pH of around 7, normal fresh meat has a pH ranging from 5.4 to 5.6 [153]. The carbohydrate glycogen is held in the muscles, but with post-mortem reduction in oxygen supply, the glycogen is broken down to lactic acid, lowering the pH. This acidification process will continue until either the glycogen is consumed or the low pH inactivates glycolytic enzymes. Where glycogen is limited, such as in animals that are very active, stressed or exposed to cold over a long period prior to slaughter, the ultimate pH of the meat is higher. Meat with a pH above 6.2 tends to have tightly packed water-retaining fibers that impede oxygen transfer and promote longer survival of oxygen-scavenging enzymes,favoringdeoxyMbratherthanoxyMb.Thepurple- red myoglobin combines with the closed structure of the muscle to absorb rather than reflect light, making the meat appear dark. This condition is commonly known as dark, firm, dry (DFD) [1, 159].