Microbial Flora of Livers, Kidneys and Hearts from Beef, Pork and Lamb: Effects of Refrigeration, Freezing and Thawing

Abstract

Aerobic plate counts (APC) of livers, kidneys and hearts obtained from beef, pork and lamb soon after slaughter were nearly always <104 and often <103 per cm2. Differences in APC of different sites of the same liver, kidney or heart, within each species, were not significant (P>0.05). APC of livers, kidneys and hearts from pork and lamb after storage for 1, 3 or 5 days at 2 C were not significantly different (P>0.05) from those at day 0. APC of beef livers, kidneys and hearts after 5 days at 2 C differed significantly (P<0.05) from those at day 0, 1 and 3. Temperature abuse of fresh organs for 6–12 h at 30 C before freezing caused major increases in count. Frozen storage of livers, kidneys and hearts (4 days at −20 C) did not cause significant changes in APC. The initial microbial flora of fresh livers, kidneys and hearts was varied with coryneform bacteria and Micrococcus sp. often constituting a major part (>25%) of the microbial flora. After storage for 5 days at 2 C, Pseudomonas sp. more often became ...