Viable but non culturable state and expression of pathogenic genes of Escherichia coli O157 : H7 in salted silver carp

Effects of intrinsic and extrinsic growth factors on virulence gene expression of foodborne pathogens in vitro and in food model systems; a review

Since foodborne diseases are one of the major causes of human hospitalization and death, one of the main challenges to food safety is the elimination or reduction of pathogens from food products throughout the food production chain. Pathogens, such as Salmonella species, Escherichia coli, Bacillus cereus, Clostridium species, Staphylococcus aureus, Listeria monocytogenes, Campylobacter species, etc., enter the consumer's body through the consumption of contaminated food and eventually cause disease, disability, and death in humans. In particular, the expression of virulence genes of these pathogens in various food environments containing them has been repeatedly reported, which is a key issue for the survival and pathogenicity of the pathogen. Hence, in this review, the interventions to prevent and control foodborne diseases, such as the application of natural preservatives, redox potential, heat treatments, high-pressure processing, and gaseous atmosphere, are discussed based on the literature. Moreover, the effects of various environmental conditions on bacterial gene expression are comprehensively reviewed. In conclusion, the effects of intrinsic and extrinsic factors on the growth and pathogenicity of bacteria are very complicated. The information obtained from the current study can be used to develop new control strategies, improve food safety, and ensure human health.

Persistence of E. coli O157:H7 in urban recreational waters from Spring and Autumn: a comparison analysis

People might get infected by pathogens found in urban recreational waters during water-contact activities, such as swimming, boating, bathing, and yachting. However, the persistence of pathogenic bacteria in those waters was not well documented. In this study, persistence of E. coli O157:H7 (EcO157) in 48 water samples (24 Spring samples and 24 Autumn samples) from the 3 urban recreational waters was investigated. Multivariate statistical analysis was performed to correlate survival data with water physicochemical properties and bacterial communities. Our data showed that EcO157 survived longer in Spring samples than in Autumn samples regardless of the lakes. Results revealed that recreational water physicochemical properties and bacterial community in Spring samples were different from those in Autumn samples. Mantel and Partial Mantel tests, as well as co-occurrence network analysis illustrated that EC salinity, TOC, and bacterial community were correlated with survival time (ttd) (p < 0.05). Variation partition analysis (VPA) indicated that bacterial community, EC, TOC, and TN explained about 64.81% of overall ttd variation in Spring samples, and bacterial community, EC, pH, and TP accounted for about 56.59% of overall ttd variation in Autumn samples. Structural equation model (SEM) illustrated that EC indirectly positively affected ttd through bacterial community. The correlation between bacterial community and ttd was negative in Spring samples and positive in Autumn samples. TN appeared a direct positive effect on ttd in Spring samples. TP displayed a direct negative effect on ttd in Autumn samples. Our results concluded that there was seasonal variation in environmental factors that directly or indirectly affected the survival of EcO157 in urban recreational waters.