EFFECT OF AMMONIA EXPOSURE ON SUBSEQUENT RANCID FLAVOR DEVELOPMENT IN LAMB

Lamb exposed to ammonia in the event of refrigeration leakage is judged to be contaminated if the meat pH has increased 1.0–1.5 units or more above normal values, but the effect of smaller ammonia concentrations is not known. The left loins from 80 lamb carcasses, processed to Accelerated Conditioning and Aging (AC&A) specifications, were exposed to ammonia gas to give an increase in pH of 0.5 unit (40 loins) or 1.0 unit (40 loins). The right loins served as paired controls. Loins were frozen and held at –20C until they were assessed for rancid flavors by a trained taste panel. Loins were assessed after 3, 6, and 12 months storage. High-ammonia samples developed a level of rancid flavors likely to be detected by consumers after 3 months storage, and low-ammonia samples after 6 months. Therefore, pH cannot be used as a measure of ammonia contamination, as exposure causing only a 0.5 pH unit rise, which is within the normal pH range of lamb, severely reduced the frozen storage life.