DFD meat — the full form is dark, firm, dry — is meat with an abnormally high pH caused by a lack of glycogen in the muscle at slaughter. When an animal is stressed, exhausted, or handled roughly before slaughter, its muscles burn through their glycogen reserves; with little glycogen left, post-mortem glycolysis produces little lactic acid, and the pH stays high instead of falling to the normal 5.4–5.7. The consequences are the textbook triad: a dark, purplish colour that consumers reject, a firm and almost sticky texture, and a dry-looking surface. Paradoxically the meat holds water well, but the high pH lets spoilage bacteria multiply faster, cutting shelf life. Prevention is all in handling — calm, rested animals with full glycogen stores produce normal meat; stressed ones produce DFD.