Effect of various types of vacuum packages and length of storage on the microbial flora of wholesale and retail cuts of beef
Seideman, S.C.; Vanderzant, C.; Hanna, M.O.; Carpenter, Z.L.; Smith, G.C.
Journal of Milk and Food Technology 39(11): 745-753
Wholesale cuts of beef (knuckles, ribs, chucks) were vacuum packaged in 3 types of packages with O2 transmission rates of 0.41-0.75, 1.09 and 2.28 cc/100 in2 per 24 h. One type of package was sealed with a clip; the others were heat sealed. Wholesale cuts were stored for 0-35 days at 1-3.degree. C, and retail cuts from ribs and knuckles were observed under retail conditions for 5 days. Differences in psychrotrophic, mesophilic and lactobacilli counts of knuckles and ribs resulting from differences in type of package usually were not statistically significant. Differences in psychrotrophic counts of retail steaks of knuckles and ribs resulting from differences in type of package used for the primal cuts were not significant. Psychrotrophic and mesophilic counts of cuts in defective packages (leakers) increased faster than those of cuts in intact packages. The initial microbial flora of knuckles, rib and chucks consisted primarily of Moraxella-Acinetobacter spp. and coryneform bacteria. During the 1st few weeks of storage at 1.degree.-3.degree. C Lactobacillus spp. already were dominant on knuckles and Microbacterium and Lactobacillus spp. predominated on ribs. After 28-35 days of storage Lactobacillus spp. were dominant on knuckles and ribs. The microbial population on chucks after 21 days of storage consisted of Lactobacillus, Microbacterium, Enterobacteriaceae, Pseudomonas, Moraxella-Acinetobacter spp. and coryneform bacteria. The microflora of cuts from defective packages was comprised of species of Pseudomonas, Microbacterium, Lactobacillus and Moraxella-Acinetobacter.