Search

In order to explore the role and function of the inlJ gene of Listeria monocytogenes (Lm) in phage sensitivity and biofilm, the inlJ gene-deficient strain Lm NJ05-ΔinlJ was constructed by homologous recombination. The growth, adhesion and invasion characteristics of the defective strain were identified. The results showed that compared with the wide-type strain Lm NJ05, the adhesion and invasion of RAW264.7 cells by Lm NJ05-ΔinlJ were significantly reduced to 20.05% and 4.42%, respectively. The efficiency of plaque formation was enhanced by 2.72 folds and phage vB-LmoM-NJ05 had a stronger lytic activity on Lm NJ05-ΔinlJ. Phage vB-LmoM-NJ05 at titers of 105 and 108 PFU/mL could completely inhibit and remove the biofilm of Lm NJ05-ΔinlJ, respectively. Transcriptional analysis of biofilm formation-related genes showed that the transcriptional levels of the degU, agrA, agrD, luxS, yneA, recA and hpt genes were significantly decreased to nearly zero in the defective strain after interacting with phage vB-LmoM-NJ05. In conclusion, deletion of the inlJ gene can enhance the phage sensitivity of Lm, and down-regulate the ability of cell invasion and biofilm formation. Therefore, the inlJ gene not only regulate Lm but also affect its interaction with phage, which lays a foundation for the development and application of phage biocontrol.

Microbial safety is crucial for China’s social and economic development in the new era, and it is an important support for national food security, public health, and social stability. In this article, we analyze the development needs and current status of the microbial safety industry considering the policy environment in China. Subsequently, we clarify the domestic and global development patterns of the industry and summarize the challenges faced by the innovation and application of pathogenic microorganism detection and control technologies in China. Furthermore, we propose a development plan for building China’s microbial safety industry. To explore a high-quality development path, China should build innovation platforms and a large scientific database regarding microbial safety, enhance personnel development for this industry, encourage leading enterprises to develop according to standards and regulations, and strengthen major system innovation and engineering technology research in the microbial safety field.

Aflatoxin B1 (AFB1), as a class I carcinogen, poses a substantial health risk to individuals. Contamination of food sources, particularly grains and nuts, with Aspergillus flavus (A. flavus) contributes to the prevalence of AFB1. The impact of global warming has spurred research into the development of AFB1 prevention technologies. While edible fungi have shown potential in detoxifying AFB1, there is a scarcity of literature on the application of Auricularia auricular (A. auricular) in this context. This study aimed to investigate the ability and underlying mechanism of A. auricular mycelia to adsorb aflatoxin B1, as well as evaluate its protective effects on the AFB1-induced liver damage in SD rats. Additionally, the effects of temperature, time, pH, and reaction ratio on the adsorption rate were examined. Combining thermodynamic and kinetic data, the adsorption process was characterized as a complex mechanism primarily driven by chemical adsorption. In SD rats, the A. auricular mycelia exhibited alleviation of AFB1-induced liver damage. The protective effects on the liver attributed to A. auricular mycelia may involve a reduction in AFB1 adsorption in the intestine, mitigation of oxidative stress, and augmentation of second-phase detoxification enzyme activity. The adsorption method for AFB1 not only ensures safety and non-toxicity, but also represents a dietary regulation strategy for achieving effective defense against AFB1. [ABSTRACT FROM AUTHOR]

The increasing incidence of diseases caused by highly carcinogenic aflatoxin M1 (AFM1) in food demands a simple, fast, and cost-effective detection technique capable of sensitively monitoring AFM1. Recent works predominantly focus on the electrochemical aptamer-based biosensor, which still faces challenges and high costs in experimentally identifying an efficient candidate aptamer. However, the direct electrochemical detection of AFM1 has been scarcely reported thus far. In this study, we observed a significant influence on the electrochemical signals of ferric ions at a gold nanoparticle-modified glassy carbon electrode (AuNPs/GCE) by adding varying amounts of AFM1. Utilizing ferricyanide as a sensitive indicator of AFM1, we have introduced a novel approach for detecting AFM1, achieving an unprecedentedly low detection limit of 1.6 × 10−21 g/L. Through monitoring the fluorescence quenching of AFM1 with Fe3+ addition, the interaction between them has been identified at a ratio of 1:936. Transient fluorescence analysis reveals that the fluorescence quenching process is predominantly static. It is interesting that the application of iron chelator diethylenetriaminepentaacetic acid (DTPA) cannot prevent the interaction between AFM1 and Fe3+. With a particle size distribution analysis, it is suggested that a combination of AFM1 and Fe3+ occurs and forms a polymer-like aggregate. Nonetheless, the mutual reaction mechanism between AFM1 and Fe3+ remains unexplained and urgently necessitates unveiling. Finally, the developed sensor is successfully applied for the AFM1 test in real samples, fully meeting the detection requirements for milk. [ABSTRACT FROM AUTHOR]

Aflatoxin biosynthesis has established a connection with oxidative stress, suggesting a prevention strategy for aflatoxin contamination via reactive oxygen species (ROS) removal. Epigallocatechin gallate (EGCG) is one of the most active and the richest molecules in green tea with well-known antioxidant effects. Here, we found EGCG could inhibit aflatoxin B1 (AFB1) biosynthesis without affecting mycelial growth in Aspergillus flavus, and the arrest occurred before the synthesis of toxin intermediate metabolites. Further RNA-seq analysis indicated that multiple genes involved in AFB1 biosynthesis were down-regulated. In addition, EGCG exposure facilitated the significantly decreased expression of AtfA which is a bZIP (basic leucine zipper) transcription factor mediating oxidative stress. Notably, KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis indicated that the MAPK signaling pathway target transcription factor was down-regulated by 1 mg/mL EGCG. Further Western blot analysis showed 1 mg/mL EGCG could decrease the levels of phosphorylated SakA in both the cytoplasm and nucleus. Taken together, these data evidently supported that EGCG inhibited AFB1 biosynthesis and alleviated oxidative stress via MAPK signaling pathway. Finally, we evaluated AFB1 contamination in soy sauce fermentation and found that EGCG could completely control AFB1 contamination at 8 mg/mL. Conclusively, our results supported the potential use of EGCG as a natural agent to prevent AFB1 contamination in fermentation industry. [ABSTRACT FROM AUTHOR]

Ultrasound (US) as a sustainable non-thermal sterilization technology that is employed either independently alone or in combination with other processing methods to eliminate food-borne pathogens in the food industry. In the present study, the synergistic effects of US combined with FeSO 4 against Vibrio parahaemolyticus were investigated. The results demonstrated that the combination of ultrasound and FeSO 4 had an excellent bactericidal activity on V. parahaemolyticus. Treatment with US (100 W) and FeSO 4 (8 μM) for 15 min could kill more than 99.9 % cells. Furthermore, the observed cell death was identified as classical ferroptosis, characterized by ferroptosis hallmarks including iron-dependent, ROS burst, membrane damage and lipid peroxide accumulation. Addition of ferroptosis inhibitor liproxstatin-1 alleviated the cell death induced by the combination treatment. Transcriptome analysis further revealed that the US-FeSO 4 treatment significantly influenced pathways related to fatty acid metabolism, ferroptosis, biofilm formation, RNA degradation, oxidative phosphorylation and other key processes, which likely contributed to the occurrence of ferroptosis. Based on these findings, we speculated that cavitation effect of US promoted the entry of Fe 2+ , leading to the generation of free radicals primarily responsible for ferroptosis by US-FeSO 4 . Taken together, this study provides valuable insights into the biological pathway involved in ultrasound sterilization and presents an alternative strategy to eradicate microorganism in food products., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Numerous counterfeit vintage Baijiu are widely distributed in the market driven by economic interest which disturb the market economic rules and damage the reputation of particular Baijiu brand. Found on the situation, the Baijiu system variation during aging period, aging mechanisms and discrimination strategies for vintage Baijiu are systematically illuminated. The aging mechanisms of Baijiu cover volatilization, oxidation, association, esterification, hydrolysis, formation of colloid molecules and catalysis by metal elements or other raw materials dissolved from storage vessels. The discrimination of aged Baijiu has been performed by electrochemical method, colorimetric sensor array or component characterization coupled with multivariate analysis. Nevertheless, the characterization of non-volatile compounds in aged Baijiu is deficient. Further research on the aging principles, more easy-operation and low-cost discrimination strategies for aged Baijiu are imperative. The above information is favorable to better understand the aging process and mechanisms of Baijiu, and promote the development of artificial aging techniques., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Authors.)