Reuterin formed by poultry-derived Limosilactobacillus reuteri HLRE05 inhibits the growth of enterotoxigenic Bacillus cereus in in vitro and fermented milk

The problem of food safety caused by Bacillus cereus contamination has been widely concerned, particularly in milk and its products, while effective prevention and control measures have not been implemented. Reuterin is a special broad-spectrum antibacterial substance produced by Limosilactobacillus reuteri via glycerol fermentation and is considered as a viable alternative to preservatives. In this study, a health poultry-derived L. reuteri HLRE05 (lineage VI strain in the evolutionary branch) was used to confirm its ability to produce reuterin, and then its basic biological activity and inhibitory capacity against foodborne pathogens were evaluated by glycerol fermentation in in vitro and fermented milk. Results showed that L. reuteri HLRE05 exhibited high resistance to hydrogen peroxide and intestinal fluids, and its adhesion rate to intestinal epithelial cells (Caco-2) reached about 80%. The content of reuterin produced by glycerol fermentation in vitro reached to 9.98 mg/mL, and the addition of glycerol to the fermentation broth could significantly improve the ability of supernatant to inhibit common foodborne pathogens. In addition, reuterin inhibited enterotoxigenic B. cereus HN001 with concentration dependent manner and restricted its adhesion rate to intestinal epithelial cells. Furthermore, L. reuteri HLRE05 produced reuterin during milk fermentation and eradicated B. cereus HN001 in a short period of time. This study highlights the potential application of natural-sourced antimicrobial approach with specific L. reuteri HLRE05 to control the safety of dairy products.