Post-Mortem pH Decline

After slaughter and exsanguination lactic acid builds up in the animal carcass causing a decline in pH. The rate of pH decline and the total drop are very important factors which affect final meat quality.

Under normal conditions, low pH values are not reached until the carcass has reached temperatures which are low enough to prevent excessive protein denaturation. If lactic acid builds up too quickly resulting in a rapid pH decline, denaturation of the muscle protein can result in loss of tenderness of the meat, loss of juiciness, and less intense (or pale) muscle coloration. In the extreme case, this is known as Pale, Soft, Exudative (PSE) condition. At the other extreme, muscle which has a very high pH during conversion to meat may be a dark, firm, and dry (DFD) condition.