The inhibition of cell-free supernatants of several lactic acid bacteria on the selected psychrophilic spoilage bacteria in liquid whole egg

The short shelf-life of pasteurized liquid whole egg (LWE) has been a technical problem of the industry for a long time, and there was an urgent need to develop relevant methodologies for the control of spoilage bacteria. In this study, the spoilage potential of the selected strains at low temperature and the inhibition of cell-free supernatant (CFS) of lactic acid bacteria (LAB) on the representative strains with strong spoilage ability was both investigated. The results showed that some high abundance strains such as Pseudomonas and Microbacterium had the strong spoilage ability which might dominate the spoilage of liquid egg products. Meanwhile, the CFS of the selected LAB had a good inhibitory effect on them, and the result was: CFS of Lactobacillus plantarum 90 > CFS of Lactobacillus rhamnosus 05 > CFS of Pediococcus pentosaceus L28-8. Also, the CFS of L. plantarum 90 had a good bacteriostatic effect on the selected representative spoilage bacteria in LWE in a dose-dependent manner. Combined with the experimental results, it is speculated that this was the result of synergistic action of many bacteriostatic substances such as organic acids and bacteriocins. Overall, this study provides a possibility for the application of CFS of LAB in pasteurized liquid egg products to extend the shelf-life.