Vacuum-packed lamb shoulders - Microbial communities

Summary

Australian export-grade vacuum-packed (VP) beef primals have notably long shelf-life. While this is an envious position in international commerce, the specific factors that control this benefit are not well understood. Previous MLA projects measured changes in sensory and microbiological properties of VP striploins and cube rolls from six Australian export abattoirs, and found substantial differences in microbiological profiles. This led to a second phase of research that showed there were no unique bacterial species among the abattoirs to explain differences in primal shelf-life, indicating that the cause was more likely due to properties of specific bacterial strains. Results from the present study support this idea, showing that strains of bacteria on VP primals from abattoirs with low bacterial growth were more sensitive to pH, lactic acid and to low concentrations of glucose. More importantly, these abattoirs have a higher proportion of strains that produce inhibitory compounds against other bacteria, with the greatest effects against bacteria of the same species. As a result, these interactions may limit the overall growth of the bacterial community, resulting in longer shelf-life and a higher quality.