Shelf-life and bacterial community dynamics of vacuum packaged beef during long-term super-chilled storage sourced from two Chinese abattoirs

This study explored the shelf-life and bacterial community dynamics of beef cuts stored at super-chilled conditions (-1 +/- 0.5 degrees C) for 20 weeks when sourced from two Chinese abattoirs, in order to determine whether domestic beef has equivalent quality as that imported from Australia. The initial total viable counts (TVC) were 4.15 and 4.87 log CFU/cm(2) in beef from abattoirs A and B, respectively at the commencement of the storage period. The TVC of beef from abattoir A was above 6.0 log CFU/cm(2) at 6 weeks and kept below 7.0 log CFU/cm(2) at 20 weeks; while the counts were above 6.0 log CFU/cm(2) at 3 weeks and reached at 7.3 similar to 7.6 log CFU/cm(2) in beef from abattoir B. The beef shelf-life was deemed less than 12 and 9 weeks in abattoirs A and B, respectively, based on the total volatile basic nitrogen (TVBN) threshold, although all samples were acceptable organoleptically. High-throughput sequencing showed that the initial bacteria community and bacterial succession during storage were different between the two abattoirs. Carnobacterium spp. and Lactobacillus spp. dominated in both abattoirs throughout 3-9 weeks while Serratia spp. co-dominated in abattoir B, and Lactobacillus spp. and Carnobacterium spp. were dominant for the rest of storage in abattoir A and B, respectively. Overall, the high initial TVC is a concern compared to imported beef from Australia. To achieve comparable shelf-life, domestic super-chilled stored beef would need to be sourced from abattoirs employing effective decontamination technologies or where strict hygiene procedures are adopted.