Agriculture and Agri-Food Canada, Lacombe, Alberta, Canada.
Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
Appl Environ Microbiol. 2019 Oct 1;85(20). doi: 10.1128/AEM.01227-19. Print 2019 Oct 15.
and are often predominant in the microbiota of vacuum-packaged (VP) meats after prolonged storage at chiller temperatures, and more so in recent studies. We investigated the antibacterial activities of and ( = 31) from VP meats by phenotypic characterization and genomic analysis. Five strains showed antibacterial activities against Gram-positive bacteria in a spot-lawn assay, with strains having an intergeneric and strains an intrageneric inhibition spectrum. This inhibitory activity is correlated with the production of predicted bacteriocins, including carnobacteriocin B2 and carnolysin for and divergicin A for The supernatants of both species cultured in meat juice medium under anaerobic conditions retarded the growth of most Gram-positive and Gram-negative bacteria in broth assay in a strain-dependent manner. and produced formate and acetate but not lactate under VP meat-relevant conditions. The relative inhibitory activity by strains was significantly correlated ( < 0.05) to the production of both acids. Genomic analysis revealed the presence of genes required for respiration in both species. In addition, two clusters of have an average nucleotide identity below the cutoff value for species delineation and thus should be considered to be two subspecies. In conclusion, both bacteriocins and organic acids are factors contributing significantly to the antibacterial activity of and under VP meat-relevant conditions. A few strains can be explored as protective cultures to extend the shelf life and improve the safety of VP meats. The results of this study demonstrated that both bacteriocins and organic acids are important factors contributing to the antibacterial activities of from vacuum-packaged (VP) meats. This study demonstrated that formate and acetate are the key organic acids produced by and demonstrated their association with the inhibitory activity of carnobacteria under VP meat-relevant storage conditions. The role of lactate, on the other hand, may not be as important as previously believed in the antimicrobial activities of spp. on chilled VP meats. These findings advance our understanding of the physiology of spp. to better explore their biopreservative properties for chilled VP meats.
和 在经过冷藏储存后，通常是真空包装（VP）肉类微生物群中的主要菌群，而且在最近的研究中更为明显。我们通过表型特征和基因组分析研究了来自 VP 肉类的 和 （ = 31）的抗菌活性。在点草坪试验中，有 5 株菌显示出对革兰氏阳性菌的抗菌活性，其中 株菌具有种间抑制谱，而 株菌具有种内抑制谱。这种抑制活性与预测的细菌素的产生有关，包括 对 和 的肉杆菌素 B2 和肉溶菌素，以及 对 的 divergicin A。在厌氧条件下，两种细菌在肉汁培养基中的培养物上清液以菌株依赖性方式延迟肉汤试验中大多数革兰氏阳性和革兰氏阴性菌的生长。在 VP 肉相关条件下， 和 产生甲酸盐和乙酸盐，但不产生乳酸盐。菌株的相对抑制活性与两种酸的产生显著相关（ < 0.05）。基因组分析显示两种细菌都需要呼吸基因。此外，两个 簇的平均核苷酸同一性低于物种划分的截止值，因此应被视为两个亚种。总之，细菌素和有机酸都是在 VP 肉相关条件下对 和 抗菌活性有重要贡献的因素。一些 菌株可以被探索作为保护性培养物，以延长 VP 肉的货架期并提高其安全性。本研究结果表明，细菌素和有机酸都是 对 VP 肉相关条件下抗菌活性的重要因素。本研究表明，甲酸盐和乙酸盐是 产生的关键有机酸，并证明了它们在 VP 肉相关储存条件下与 carnobacteria 抑制活性的关联。另一方面，乳酸盐在 对冷藏 VP 肉的抗菌活性中的作用可能不如之前认为的那么重要。这些发现增进了我们对 生理的理解，以更好地探索其在冷藏 VP 肉中的生物保鲜特性。
