The microbiology and storage stability of vacuum packed lamb

Summary Lamb joints (shoulders, loins and legs) stored in vacuum packs at 0–1°C remained unspoiled for 6 weeks, but since the aerobic storage life at 5°C (retail shelf life) of lamb after holding in vacuum packs at 0–1°C for 6 weeks was only 2 days, vacuum storage should be limited to a maximum of 4 weeks in practice. Brochothrix thermosphacta, Moraxella spp, and Moraxella‐like organisms were predominant on aerobically spoiled lamb and the preservative effect of vacuum packing resulted from the inhibitory effects of the high carbon dioxide (>20%) and low oxygen concentrations (<1%) which developed in the packs. Brochothrix thermosphacta was not completely inhibited, however, and with lactic acid bacteria was the possible cause of cheesy/sour odours which terminated vacuum packed storage life.