Cooperation of lactic acid bacteria regulated by the AI-2/LuxS system involve in the biopreservation of refrigerated shrimp

Abstract Litopenaeus vannamei is an extremely perishable food because of rapid microbial growth and chemical degradation after harvesting. Biopreservation is a food preservation technology based on the addition of “positive” bacteria to kill or prevent the growth of undesirable microorganisms. In this study, the cooperation between lactic acid bacteria (LAB) strains ( Lactobacillus plantarum AB-1 and Lactobacillus casei ) regulated by the AI-2/LuxS was investigated in vitro and on shrimp. The antimicrobial activity of L. plantarum AB-1 was significantly increased in the co-culture compared with the mono-culture in vitro , and the transcription of the quorum sensing luxS gene and bacteriocin regulatory operons ( plnB and plnC ) in L. plantarum AB-1 were also significantly increased in co-culture ( P L. plantarum AB-1 might be related to the LuxS/AI-2 quorum sensing (QS) system. The results were confirmed by adding the exogenous AI-2 molecule signal to L. plantarum AB-1 in vitro . In the on shrimp experiments, the spoilage organisms (mainly Shewanella baltica ) in shrimp samples were significantly inhibited after co-inoculation with L. plantarum AB-1 and L. casei , and the values of total volatile basic nitrogen (TVB-N) and pH in co-inoculated shrimp were also significantly decreased ( P L. plantarum AB-1 and L. casei in shrimp is an effective strategy for biopreservation of shrimp.