Safety and quality assessment of beef exposed to low levels of ammonia

This study was designated to provide information about the safety and quality effects of exposure to low levels of ammonia over time on beef semitendinosus samples. Muscles (48 hr postmortem) were trimmed of external fat and sliced into 0.9 cm steaks. Steaks were exposed to different levels of ammonia (0, 500, 1000, 2500, and 5000 ppm) for different exposure times (0, 5, 10, and 20 min). Ammonia content of beef increased and was correlated to the ammonia treatments. Exposure to ammonia increased (P < 0.05) the pH of the meat. The pH of the meat surface was higher than the pH of ground samples and aeration of contaminated meat (30 and 60 min) was effective in reducing (P < 0.05) the pH. Percent water holding capacity (%WHC) increased and the losses of cooking and thawing were lower. The color of uncooked, treated steaks was lower in b* and L* values with no effect (P > 0.05) on a* values. Cooked color was more (P < 0.05) pinkish (a* values) for ammonia treated steaks with no effect on b* and L* values. Display red color (a* values) persisted longer (P < 0.05) for ammonia treated steaks when compared to the controls. The absorbance spectra (400–700 nm) of treated uncooked beef were similar to untreated counterparts and both were different from cured spectra. Cooked, treated beef spectra were similar to the oxymyoglobin spectra of fresh (uncooked) samples and that explained the undercooked phenomena in fully cooked ammonia treated beef. The GC analysis indicated that no traces of 4-methylimidazole or other imidazole derivatives were found in either control or ammonia treated meat samples. The exposure to ≥1000 ppm ammonia for ≥10 min affected the quality attributes of meat.