Spoilage characteristics and interaction of Lactobacillus curvatus and Brochothrix thermosphacta

In this study, inoculated experiments of mono-culture (Lactobacillus curvatus (M) and Brochothrix thermosphacta (S)) and co-culture (MS) were conducted to explore spoilage characteristics and interaction between two strains. Physicochemical analyses of pH, total viable counts, total volatile basic nitrogen and color in braised chicken were conducted. In addition, volatile organic compounds in meat products were analyzed using headspace solid phase microextraction combined with gas chromatography-mass spectrometry. Moreover, a transcriptomic analysis in vitro model was conducted to elucidate the main metabolic pathways. The results showed that the butyric acid was predominant in the M and MS groups at the end of the storage period. The co-culture produced more spoilage metabolites (including 3,4-dimethoxycinnamic acid, and 3,5-dimethoxycinnamic), which could be a potential spoilage biomarker. In the vitro model, 35 remarkable enriched metabolic pathways were identified. Results showed that the co-culture stimulated Lactobacillus curvatus to enhance its starch and sucrose metabolism, a two-component system, but down regulated the phosphotransferase system, amino sugar, nucleotide sugar metabolism, and fructose and mannose metabolism. Brochothrix thermosphacta faced nutritional competition by down-regulating its valine, leucine, and isoleucine biosynthesis—branched-chain dibasic acid metabolism. This study provides insight into spoilage mechanisms to help development of packaging technologies for braised chicken.