Postbiotic wash treatments: A novel post-harvest approach to reduce Salmonella and enhance egg safety

Abstract

SalmonellaEnteritidis (SE) contaminated eggs are the leading cause of foodborne outbreaks. Egg contamination occurs from environmental sources and SE-colonized hens. Consumption of these contaminated eggs results in salmonellosis in humans. Hence, there is a need for effective post-harvest solutions to control SE on eggs. Here we evaluated the efficacy of two novel postbiotics extracted from probiotics, Lactobacillus rhamnosus NRRL-B-442 (LR) and Lactobacillus paracasei DUP 13076 (LP), as post-harvest wash treatments to reduce egg contamination. For this study, fresh table eggs were randomly assigned to treatments including control (water), MRS control (MRSC – water with 40 % v/v MRS), 200 ppm chlorine (industry control), water with 40 % v/v LP postbiotic (LPP) and water with 40 % v/v LR postbiotic (LRP). Inoculated eggs (SE ∼8 log CFU/egg) were either dip or electrospray (ES) washed using different treatments. Immediately following wash and at different times during 21-day refrigerated storage, outer surface, inner shell surface and internal contents of eggs were sampled to enumerate surviving SE populations. The ES application of LRP and LPP reduced SE populations on outer surface to below detection limits by day 7 of storage with <11 % of internal contents testing SE positive. With dip wash, postbiotic treatment reduced SE populations by > 5 log CFU/egg. Overall, postbiotic application by ES or dipping significantly reduced SE populations on eggs (P ≤ 0.05) throughout the storage without impacting egg quality (P > 0.05). Overall, postbiotics can serve as a safe, effective, and organic friendly approach to enhance post-harvest egg safety.