Spoilage Characteristics and Interaction of Lactobacillus Curvatus and Brochothrix Thermosphacta

Abstract

Lactic acid bacteria and Brochothrix thermosphacta are common spoilage microorganisms in meat. The aim of this study was to investigate the interaction of Lactobacillus curvatus (M) and Brochothrix thermosphacta (S) in inoculated experiments as mono- or co-culture (MS). Physicochemical indicators (pH, total viable counts, total volatile basic nitrogen (TVB-N) and color) of braised chicken were detected, while volatile organic compounds were analysed with headspace solid phase microextraction combined with gas chromatography-mass. Meanwhile, the work made transcriptomic analysis of spoilage bacteria in vitro model to explain metabolism. These results showed that the butyric acid almost existed in the M and MS groups at the end of storage period. The co-culture produced more spoilage metabolites (3,4-dimethoxycinnamic acid, 3,5-dimethoxycinnamic), which could be as potential spoilage biomarker. In vitro model, it was observed that there were 35 remarkable enriched metabolic pathways. The results indicated that the co-culture stimulated Lactobacillus curvatus to enhance its starch and sucrose metabolism, two-component system, while down-regulating the phosphotransferase system, amino sugar and nucleotide sugar metabolism, as well as fructose and mannose metabolism. Brochothrix thermosphacta faced nutritional competition by down-regulating its valine, leucine and isoleucine biosynthesis, C5-branched-chain dibasic acid metabolism.

Keywords: Lactobacillus curvatus, Brochothrix thermosphacta, Spoilage microorganisms, Transcriptomic, Braised chicken