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The widespread presence of foodborne pathogenic bacteria biofilms in the food supply chain has significantly negative impacts on food microbial safety, posing a serious threat to the health and safety of consumers. Weakening the interaction between food contact surfaces and biological pollutants and reducing biological adhesion by changing the physicochemical properties of food contact surfaces can effectively reduce the formation of biofilms, thereby ensuring the microbial safety of food. This article summarizes recent progress in research on anti-biofouling materials. First, the application of the DLVO theory to quantify the interaction between biological pollutants and material surfaces is reviewed. Then, this paper classifies the existing anti-biofouling materials into two categories: hydrophobic and hydrophilic, and summarizes the typical methods to construct each type of anti-biofouling materials and their anti-biofouling mechanisms. Finally, based on the current status of the application of anti-biofouling materials in the food industry, an outlook on future development directions is provided. This article aims to provide theoretical guidance for the development of new anti-biofouling materials in order to better ensure the microbial safety of food.

Salmonella is one of the most common pathogens causing foodborne diseases. Eggs and egg products are important food vehicles for its transmission. Among the many serotypes of Salmonella, S. enterica serovar Enteritidis has a unique advantage in surviving egg white because of its resist to antibacterial molecules in egg white, which can lead to food poisoning. In recent years, the survival strategies of S. enteritidis serovar Enteritidis in egg white have been explored by using molecular biological techniques such as transposon mutations, in vivo expression, high-throughput sequencing and omics, and some key metabolic pathways and stress resistance-related genes/proteins have been discovered. However, the function of stress resistance-related genes has not been fully revealed, and there is a lack of a comprehensive summary of the existing research. Therefore, the current situation and transmission routes of Salmonella contaminated eggs are briefly introduced in this review. Furthermore, the latest progress in research on the survival mechanism of S. enteritidis serovar Enteritidis in egg white is summarized from the perspectives of nutrient availability, membrane stress response, deoxyribonucleic acid (DNA) damage repair, alkaline pH adaptation, osmotic stress response and energy metabolism. Finally, the biological control methods for Salmonella are summarized, including vaccines, bacteriophages, and probiotics. Meanwhile, future research directions are discussed. This article will provide an important reference for effective control of Salmonella in eggs and egg products.

The viable but nonculturable (VBNC) state refers to a state in which bacteria lose their ability to grow and reproduce in conventional media under adverse environmental stress conditions. Bacteria in the VBNC state are usually still metabolically active and remain pathogenic and virulent. Bacteria in the VBNC state can recover and return to a state where they can be cultured normally under certain suitable conditions, posing potential risks to food safety. In this review, the morphological, physiological, biochemical and biomacromolecular characteristics of bacteria, especially foodborne pathogens, in the VBNC state are comprehensively described. Meanwhile, various factors that induce bacteria to enter the VBNC state, including temperature and pH unsuitable for bacteria survival, are summarized. The laboratory conditions for bacterial recovery from the VBNC state are outlined with special reference to adequate nutrition as an indispensable factor for recovery from the VBNC state. Finally, the major methods for the detection of bacteria in the VBNC state are discussed, including molecular biological methods, flow cytometry, and optical microscopy. Molecular biological methods have been widely used in the detection of bacteria in the VBNC state due to their advantages of accuracy, rapidity and high sensitivity. This review provides more ideas for further research on the induction, resuscitation and detection of foodborne pathogens in the VBNC state.

Contamination of spoilage and pathogenic microorganisms in food substrates can negatively influence food quality and threaten food safety. The application of physicochemical antimicrobial strategies can effectively inhibit the growth and reproduction of harmful microorganisms, but may also cause irreversible negative effects on food quality. Some antagonistic yeasts alone or combined with antimicrobial agents can effectively control harmful microorganisms. This review systematically and comprehensively summarizes the existing literature on the antimicrobial effects and mechanisms of yeasts and their derivatives from the above two aspects. The sources, species and mechanism of action of antagonistic yeasts as well as their antimicrobial effects when combined with other antimicrobial technologies are discussed. Additionally, the advantages and limitations of yeast as a natural drug carrier combined with various chemical antimicrobial agents are analyzed. This review aims to provide a scientific reference for developing new yeast-based antimicrobial agents, which will be helpful in improving food quality and ensuring food microbial safety.

Benzalkonium chloride is a quaternary ammonium compound with bactericidal activity, which is widely used in domestic and healthcare settings as well as in food processing environments. It plays an important role in the prevention and control of foodborne pathogens. However, the presence of biofilms or improper use of benzalkonium chloride may enable foodborne pathogens to adapt to bactericides, affecting the tolerance to homologous or heterologous biocidal agents. The review summarizes the relationship between the adaptation of foodborne pathogens to benzalkonium chloride and their tolerance to this biocide. The reasons for the increased tolerance to benzalkonium chloride are explained from the perspectives of the expression of efflux pump genes, cell membrane modification, and the formation of the viable but non-cultivable (VBNC) state. Furthermore, the influence of benzalkonium chloride adaptation on the antibiotic resistance of foodborne pathogens is discussed, and the reasons for the increased antibiotic resistance are summarized from the perspectives of biofilm formation, spontaneous mutations, horizontal gene transfer, and the role of efflux pumps in antibiotic resistance. This review could help understand the mechanism of the adaption of foodborne pathogens to benzalkonium chloride and provide a reference for the rational use of biocides and the prevention and control of foodborne pathogens.

Microbial communities interact in a complicated way, which can have a detrimental effect on the host’s health either individually or collaboratively. By employing causal inference methods to analyze the characteristics of the relationship between the microbiota and host observation data, the mechanism of action of microorganisms on host health can be inferred, which will help to reduce the possibility of causing unfavorable health consequences. This article reviews recent progress in the application of causal inference in the field of microbiological research, introduces the conception and development of causality, describes the paths of causal inference, modeling and interpretation, and summarizes the causal inference methods and their applications in various fields especially in the microbiological field. However, the mechanism of the causality between microbial communities and their external environments is not yet understood fully. Applying causal inference methods in research on microbial communities will be a hot topic in the future. Thus, the theory and methods of causal inference need be further refined to elucidate the interaction mechanism of microbial communities and their causality with human health.

Foodborne pathogenic bacterial biofilm is a spatially structured multi-cellular community that is adhered to food contact surfaces. Conventional disinfection methods cannot effectively prevent and control bacterial biofilm due to its strong adhesiveness and stress resistance, causing food safety hazards and a serious effect on consumer health. In this article, recent studies on the formation mechanism and control strategies of foodborne pathogenic bacterial biofilm are reviewed. The roles of the functions of bacterial long-chain appendages, quorum sensing system and extracellular polymeric substances (EPSs) in the formation of bacterial biofilm are summarized and discussed based on improved biofilm adhesiveness, changed bacterial state, and enhanced stress resistance. This review divides the existing strategies for biofilm prevention and control into three categories: physical, chemical, and biological, and analyzes the principle, advantages and disadvantages of each category in order to provide a theoretical reference for the development of more efficient strategies for biofilm prevention and control in the food field to achieve better prevention and control of food microbial safety.

ObjectiveThe contamination of foodborne pathogens in ready-to-eat fruits and vegetables in Shanghai was analyzed to provide a scientific basis for food safety， risk assessment and related supervision.MethodsFrom June to September 2021， a total of 143 batches of 12 kinds of ready-to-eat fruits and vegetables such as lettuce， chicory， and cherry tomatoes were collected from farmers’ markets， supermarkets， and e-commerce platforms. The total number of bacterial colonies， Salmonella， Listeria monocytogenes， Staphylococcus aureus， Cronobacter spp. and Shiga toxin-producing Escherichia coli in the samples were tested according to National Food Contamination and Harmfulness Risk Monitoring Manual.ResultsAmong the 143 batches， foodborne pathogens were detected in 68 batches， with a total detection rate of 47.55% （68/143）. A total of 79 strains of foodborne pathogens were detected. The detection rate of Staphylococcus aureus was the highest （32.87%， 47/143）， followed by Cronobacter spp. （20.98%， 30/143）， Salmonella （0.70%， 1/143）， Listeria monocytogenes （0.70%， 1/143）， Shiga toxin-producing Escherichia coli （0.00%）. Furthermore， the detection rate was higher in different ready-to-eat fruits and vegetables： chicory （17.33%）， cucumber （17.14%）， cherry tomatoes （16.00%）， and honeydew melon （15.38%）， respectively. Meanwhile， the contamination rate of pathogens in ready-to-eat fruits and vegetables from farmers’ markets， supermarkets， and e-commerce platforms was relatively high.ConclusionReady-to-eat fruits and vegetables in Shanghai are contaminated by foodborne pathogens. The prevention and control of the contamination of post-harvest fruits and vegetables should be strengthened to reduce the risk of foodborne disease outbreaks.