The protective effect of Bdellovibrio‐and‐like organisms (BALO) on tilapia fish fillets against Salmonella enterica ssp. enterica serovar Typhimurium

Aims: To characterize freshwater Bdellovibrio‐and‐like organisms (BALO) isolated in China and examine their potential in controlling growth of Salmonella enterica ssp. enterica serovar Typhimurium on tilapia fillets. Methods and Results: Four BALO isolates were recovered from a pond in Yanzhou of Shandong province, China, with Salm. Typhimurium as prey using double‐layer agar method. Partial 16S rDNA sequencing analysis identified BD2GL, BD5GL and BDXGL as Bdellovibrio bacteriovorus and BD2GS as a Peredibacter sp. Lysis experiments on 32 potentially pathogenic strains revealed that BALO lysis rates are in the range of 56·3–65·6%. On the five Salmonella strains tested, only BD2GS achieved 100% lysis rate. When applied on tilapia fillets against Salm. Typhimurium, BD2GS showed its growth control potential. Cell increments of Salm. Typhimurium were significantly lower (P < 0·05) in two BD2GS‐treated groups compared to control and low‐dose group (BD2GS to prey ratio, 1 : 1) was more effective than high‐dose group (BD2GS to prey ratio, 10 : 1) in controlling Salm. Typhimurium growth. Conclusions: Results of this study indicated that BD2GS could control Salm. Typhimurium growth on tilapia fillets. Significance and Impact of the Study: BALO could be used as a live protective culture in controlling bacterial growth and ensure food safety.