Bacterial succession and reduced antibiotic resistance gene burden in rabbit meat under low-oxygen modified...

Optimal gas compositions of O₂, N₂, and CO₂ in modified atmosphere packaging (MAP) have been shown to inhibit spoilage in meat and meat products effectively. This study investigated the impact of three different MAP methods (MAPa: 70% O₂ / 30% CO₂; MAPb: 70% N₂ / 30% CO₂; MAPc: 20% O₂ / 60% N₂ / 20% CO₂) and air packaging (CK) on the physicochemical characteristics, spoilage dynamics, and bacterial succession of rabbit meat during 8 days of chilled storage. The MAPc meat consistently had the lowest TVB-N and TBARS values, and consequently exhibited the slowest spoilage progress among all groups. 16S rRNA sequencing revealed dramatic shifts in the microbial community from Shigella-, Bacteroides- and Lactococcus-dominant rabbit meat before 4 days of storage to Brochothrix- and Psychrobacter-dominated spoilage communities as storage time progressed. Notably, Psychrobacter was markedly inhibited in MAPc (11.03%) compared to CK (42.45%) at day 8. Metagenomic analysis conducted on MAPc and CK samples identified 183 ARGs, mostly tetracycline resistance genes. Moreover, Tet(L), CfxA3, Tet(Q), ANT(4')-lb, and Msr(D) were identified as the predominant ARGs in rabbit meat, while MAPc significantly reduced the relative abundance of AcrB, Tet(M), MacB, Sul2, APH(6)-ld, Tet(S), and Msr(E). Most of the ARGs were primarily harbored by Psychrobacter, Pseudomonas, and Brochothrix thermosphacta. Importantly, at the near-spoiled stage, ARG abundance increased in CK group but decreased in MAPc samples, suggesting that low-O₂ MAP treatment reduces ARG levels. Overall, low-O₂ MAP (MAPc) represents a promising preservation strategy that extends the shelf life of rabbit meat while reducing ARG abundance.