Effect of Initial Internal Temperature and Storage Temperature on the Microbial Flora of Vacuum Packaged Beef

Abstract

Large increases in bacterial counts of vacuum-packaged top sirloin butts occurred between 7–14 days of storage at 5.5 C and between 14–21 days of storage at 0 C. Differences in post-mortem chill temperature (1 C vs 7.2 C) of the cuts did not significantly influence the counts of the primal cuts during refrigerated storage for up to 35 days. Counts of steaks from primal cuts stored for 21–35 days at 5.5 C usually were somewhat higher than those from cuts held at 0 C. Lactobacillus species and members of the Enterobacteriaceae dominated the psychrotrophic microbial flora of cuts stored for 35 days. Psychrotrophic and mesophilic counts of cuts from defective bags (leakers) increased rapidly and consisted primarily of Pseudomonas species.