Oxidative Stability and Microbial Ecology of Fresh Beef with Extremely Long Shelf-Life

Abstract

This study was aimed at assessing the pigment and lipid stability and characterising the microbial ecology by classical methods and metagenetics in beef with an extremely long shelf-life. Bovine longissimus thoracis et lumborum subprimals from different origins (Australia, Brazil, Ireland, and United Kingdom), displaying a shelf-life from 35 to 140 days in vacuum packaging, were aged at −1 (subzero storage) or a −1/+4°C two-level stepwise scheme. At different times, samples were repackaged under a high-oxygen atmosphere (70/30% O2/CO2) and stored at 4°C for two days and then 8°C for five days to simulate retail distribution. Subzero storage inhibited the growth of total aerobic mesophilic flora and Enterobacteriaceae during ageing in vacuum ( p < 0.001 ). During simulated retail distribution, the shelf-life was limited by metmyoglobin formation and excessive lactic acid bacteria growth. Classical microbiological methods underestimated the lactic acid bacteria count. Nonetheless, metagenetics evidenced, specifically in Australian samples, high proportions of Carnobacterium maltaromaticum, a lactic acid bacterium that may have contributed to the extremely long shelf-life of Australian beef.

Carnobacterium maltaromaticum as bioprotective culture against spoilage bacteria in ground meat and cooked ham

“…2). These findings corroborate the results of a previous study by Imazaki et al (2023), which demonstrated an inhibitory effect of the same C. maltaromaticum isolated strains on Enterobacteriaceae in beef stored in a low-oxygen atmosphere. The inhibition of this group of bacteria was also reported for Carnobacterium spp.…”

“…As noticed, C. maltaromaticum growth remained practically constant during storage and was barely affected by the inoculated or indigenous spoilage microbiota. The high population of Carnobacterium in these meat matrices is sustained by a previous study by Imazaki et al (2023), who isolated the C. maltaromaticum strains used in the present study from a long-term vacuum-packaged Australian beef, of which 98% of the final microbial composition was predominantly Carnobacterium. Other studies show that C. maltaromaticum can predominate over the spoilage population (Laursen et al, 2005) and persist in chilled meat until the end of the shelf-life (Holck, Pettersen, Moen, & Sørheim, 2014; Zhang, Badoni, Gänzle, & Yang, 2018).…”

“…The negligible influence of the C. maltaromaticum strains on meat color was previously reported in raw and cooked beef patties (Casaburi et al, 2011;Imazaki et al, 2023;Said et al, 2019) and in ham (Danielski et al, 2020).…”

“…In this study, we used a pool of strains of C. maltaromaticum (CM_B824, CM_B827, and CM_B289) with a previously demonstrated noteworthy antilisterial effect in sliced cooked ham (Danielski et al, 2020). These strains were selected from a group of eight C. maltaromaticum isolates dominant in vacuum-packed Australian bovine longissimus thoracis et lumborum with an extremely long shelf-life of 140 days at − 1 • C. Genome sequencing revealed that the isolates belonged to three different genetic groups, all harbouring genes to produce carnobacteriocin BM1 and B2 (only CM_B824) (Imazaki et al, 2023).…”