Abstract:Objective A hybrid model based on bidirectional short term memory （BiLSTM） and Transformer was constructed to predict the population behavior of Listeria monocytogenes under different environmental conditions.Methods In view of the limitations of traditional machine learning methods in processing complex time series data， an innovative solution combining BiLSTM and Transformer model is proposed to effectively capture the long and short term dependence of time series and improve the prediction accuracy. The model input includes characteristics such as temperature， water activity， pH value， time and whether it is the initial bacterial concentration， etc. After data preprocessing， feature standardization and category coding， the trained model is used for prediction. The experimental data of L. monocytogenes from ComBase database were used to verify the model.Results The model performed well for several food groups， including beef， pork， medium， seafood and fruits， with R2 values of 0.72， 0.65， 0.85， 0.81 and 0.81， and with RMSE values of 1.17， 1.15， 0.89， 0.93 and 0.83， respectively. The results showed that the model could accurately capture the changing trend of bacterial population. By calculating the coefficient of deviation （B_f） and accuracy （A_f）， the advantages of the model in forecasting accuracy and robustness were both verified.Conclusion The BiLSTM-Transformer hybrid model as an efficient and accurate method for predicting bacterial population behavior， can contribute to bacterial prediction in the field of food safety.

Abstract:Objective To address the false-negative risk associated with trace contamination of severe acute respiratory syndrome coronavirus 2 （SARS-CoV-2） on cold-chain food and packaging material surfaces， this study aimed to develop a highly sensitive and quantifiable multiplex detection method.Method Based on multi chip-based digital PCR （multi cdPCR） technology， we simultaneously targeted the ORF1ab， N， and E genes of SARS-CoV-2. Several parameters were optimized， including primer concentration， probe， and annealing temperature， and the methodological performance was evaluated. Additionally， the viral nucleic acid load was analyzed under simulated contamination conditions on cold-chain food and packaging material surfaces.Results The multi cdPCR detection method could simultaneously identify all three gene fragments of SARS-CoV-2. The detection limit for the ORF1ab gene was 1.36 copies/μL， while the detection limits for the N and E genes are both 0.96 copies/μL. This method demonstrated high specificity， accuracy， and good repeatability， with coefficient of variation less than 1.7%. Analysis of 70 blinded， presumptively positive samples showed positive rates of 72.9% for multi cdPCR， whereas real-time fluorescence quantitative PCR gave a rate of 11.4%. Moreover， the decline of viral nucleic acid load with increasing temperature was more pronounced on food surfaces than on packaging material surfaces.Conclusion The multi cdPCR method established in this study enables the detection of low viral load of SARS-CoV-2 on cold-chain food and packaging material surfaces， thereby offering a practical tool for the safety supervision of cold-chain foods.

Abstract:Objective To establish a highly sensitive and high-throughput analytical method for the simultaneous determination of 38 organic ultraviolet absorbents （OUVAs） by pass-through solid phase extraction （SPE） coupled with ultra performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS）.Methods The samples were extracted with acetonitrile and purified using Oasis PRiME HLB （60 mg/3 mL）. The separation was performed on an Acquity UPLC BEH C₁₈ column （100 mm×2.1 mm， 1.7 μm） employing gradient elution with methanol-0.1% formic acid in water （positive ionization mode） and methanol-0.1% ammonia in water （negative ionization mode） as mobile phases. Mass spectrometry analysis was conducted using positive and negative ion electrospray ionization sources （ESI⁺/ESI^-）， scanned in multiple reaction monitoring （MRM） mode， and quantified using the stable isotope internal standard method.Results The 38 OUVAs exhibited good linearity within their respective linear ranges （R2≥0.998 3）， with method detection limits （MDLs） ranging from 0.013 to 0.72 μg/kg and method quantification limits （MQLs） from 0.04 to 2.17 μg/kg. Recoveries of the 38 OUVAs at three different spiking levels ranged from 75.5% to 116.2%， with relative standard deviations （RSDs） between 0.93% and 10.38%.Conclusion This method is simple， highly sensitive and is expected to become a reliable analytical approach for the trace determination of 38 OUVAs.

Abstract:Objective A method was developed for the simultaneous determination of seven food additives in prepared pork dishes using gel permeation chromatography cleanup coupled with ultra-high performance liquid chromatography-tandem mass spectrometry.Methods Samples were extracted using ultrasound-assisted extraction with acetonitrile containing 0.2% formic acid. The extracts were purified by gel permeation chromatography to remove interfering substances. Chromatographic separation was performed using an HSS T3 column （2.1 mm×100 mm， 1.8 μm）. The mobile phase consisted of methanol （A） and an aqueous solution of 0.01% formic acid containing 10 mmol/L ammonium acetate （B）， using gradient elution. Detection was performed using tandem mass spectrometry in multi-reaction monitoring mode. Quantification was carried out using the blank matrix matching external standard method.Results The seven food additives showed good linearity over the concentration range of 4.00-400.00 μg/kg， with correlation coefficient （r） greater than 0.998. The limits of detection and quantification were 0.50-2.00 μg/kg and 2.00-4.00 μg/kg， respectively. Recovery experiments were conducted at three concentration levels （low， medium， and high） in braised pork， preserved mustard greens braised pork and pork meatballs. The recovery rates ranged from 73.2% to 103.4%， and the relative standard deviations were 0.54%-9.3%.Conclusions The method exhibits excellent sensitivity， high and stable recovery rate， efficient purification， and good repeatability， thus providing a reliable solution for qualitative and quantitative detection of food additives in prepared pork dishes.

Abstract:Objective To explore the species-level distribution and antimicrobial resistance of Cronobacter spp. isolated from condiments and cereal-based foods across 19 provinces （autonomous regions， municipalities） in China， and provide data support for analyzing the epidemiological patterns and conducting related risk assessment of this pathogen.Methods PCR amplification and Sanger sequencing were performed to analyze the fusA gene of 457 Cronobacter isolates from food samples across 19 provinces （autonomous regions， municipalities） in 2022， and from which positive isolates were randomly selected for antimicrobial susceptibility testing.Results Among the 457 Cronobacter isolates， which comprised six species， C. sakazakii and C. malonaticus accounted for 72.65% （332/457） and 16.19% （74/457）， respectively. Of 93 isolates tested for antimicrobial susceptibility， 47.31% （44/93） were resistant to at least one antibiotic. Notably， the resistance rate was 46.24% （43/93） against cefazolin， whereas resistance to ampicillin， nitrofurantoin， and trimethoprim/sulfamethoxazole was 1.08% for each antibiotic. Phylogenetic cluster analysis of fusA indicated a potential association between the phylogenetic groups of Cronobacter species and antimicrobial resistance.Conclusion This study demonstrated that the major species of Cronobacter isolates from condiments and cereal-based foods in China were C. sakazakii and C. malonaticus. It further revealed species-specific differences in antimicrobial resistance， particularly to cephalosporins， suggesting a potential association between species-level distribution and resistance characteristics. These findings provide scientific evidence to support risk assessment and the development of control strategies for Cronobacter in relevant food products.

Abstract:Objective To analyze the contamination of Salmonella in prepared dishes from broilers in Zhejiang， China， and to evaluate the risk of Salmonella infection in the population.Methods From 2020 to 2023， quantitative detection of Salmonella in prepared chicken dishes from retail sources in Zhejiang was conducted. Based on the results of the 2024 survey on the consumption behavior of prepared dishes among urban residents， the Salmonella risk assessment of prepared chicken dishes was carried out using the rapid quantitative microbiological risk assessment （sQMRA）.Results The detection rate of Salmonella in prepared chicken dishes from retail sources in Zhejiang 2020—2023 was 13.3% （44/330）. The annual expected number of cases of Salmonella infection among Zhejiang residents due to prepared chicken dishes was 1 594， with a probability of illness at 3.11×10^-5， which was slightly lower than the number of cases reported by the monitoring system.Conclusion Great attention need to be paid to health risk posed by Salmonella. Cross-contamination control should be strengthened in transportation， retail， breeding， and processing stage of prepared dishes made from broiler chickens. Simultaneously， supervision and management of such products in the retail sector should be enhanced， and a monitoring and early warning network for foodborne diseases should be established， and therefore， systematically reduced the risk of foodborne diseases related to Salmonella.

Abstract:Objective To initially understand the current status of awareness and consumption behavior of prepared dish consumers， and to provide data support for the food safety risk assessment of prepared dishes.Methods A questionnaire survey was conducted on 600 prepared dish consumers aged 18 and above from a city in Hebei Province in 2024， using the method of convenience sampling. Face-to-face surveys were conducted and data were collected through a tablet system. The χ2 test， Wilcoxon Rank Sum Test， and Kruskal-Wallis H Test were used to compare the attitudes， consumption ratios， and consumption volumes among prepared dish consumers.Results Among prepared dish consumers in this area， the 30-39 age group constituted the largest segment （32.83%）， followed by the 40-49 age group （26.83%）. Among prepared dish consumers， 32.50% had a college degree or higher. A total of 99.67% of prepared dish consumers had heard of prepared dishes， and most of them obtained relevant information through new media （66.55%）. Most consumers held a neutral （56.67%） or supportive （31.17%） attitude towards prepared dishes. The main reasons for opposing prepared dishes were lack of freshness （82.22%）， potential food safety issues （80.00%）， and insufficient nutrition and healthiness （68.89%）. Attitudes toward prepared dishes differed significantly by gender （χ2=8.154，P=0.043）. Convenience was the primary reason for purchasing prepared dishes （accounting for 79.33%）， while food safety and freshness remained key concerns for consumers. The consumption of meat-based prepared dishes was the highest （68.67%）， followed by vegetable-based prepared dishes （16.00%） and aquatic product-based prepared dishes （11.33%）. There were statistically significant differences in the consumption proportions of meat-based and aquatic product-based prepared dishes among age groups （meat： P=0.037； aquatic products： P=0.031）. However， no significant differences were observed in the average monthly consumption by gender， age group， or educational level （all P>0.05）. There was no significant differences in the consumption frequency and consumption among different types of prepared dishes. Individuals with a higher level of education were more likely to purchase aquatic prepared dishes.Conclusion Prepared dish consumers in the study area demonstrated high awareness but a neutral attitude towards these products， with consumption behavior primarily driven by convenience. Meat-based prepared dishes exhibited the highest consumption proportion， which was influenced by age. When conducting food safety risk assessments in this area， consumption proportion should be prioritized as a key parameter， with special consideration given to age-specific consumption patterns and variations in risk exposure.

Abstract:Objective To investigate a botulism outbreak caused by consumption of homemade pickled eggs in Weihai City， Shandong Province， and to provide reference for future prevention and control measures.Methods A population-based epidemiological investigation was conducted in accordance with the Technical Guidelines for Epidemiological Investigation of Food Safety Accidents （2012 edition）. Both descriptive and analytical epidemiological methods were employed for data analysis. Botulinum toxin genes in leftover food， environmental samples， and biological specimens were detected using real-time quantitative polymerase chain reaction （qPCR）. Clostridium botulinum strains were isolated and botulinum toxin was typed with reference to GB 4789.12—2016. Furthermore， whole-genome sequencing （WGS） and phylogenetic analysis were performed on the isolates.Results Among the 8 individuals exposed to the pickled eggs， 5 developed botulism， yielding an attack rate of 62.50% （5/8）. None of the unexposed individuals became ill. Retrospective cohort analysis identified the pickled egg as a risk factor （P<0.001）. The incubation period ranged from 13.5 to 67.5 hours. Predominant clinical manifestations included fatigue， blurred vision， ptosis （each 100.00%）， as well as nausea and vomiting （each 80.00%）. A total of 12 C. botulinum were isolated. All strains were positive for the type A botulinum toxin gene tested by qPCR. Mouse bioassay confirmed the presence of type A botulinum toxin in all 7 enrichment cultures. WGS analysis revealed that these isolates were closely genetically related.Conclusion This outbreak was confirmed as a botulism outbreak caused by the consumption of homemade pickled eggs contaminated with C. botulinum producing type A botulinum toxin. It is recommended that targeted health education be carried out among high-risk regions and populations regarding the processing， storage， and consumption practices to enhance their awareness of safety precautions for such foods.

Abstract:In recent years， the issue of food authenticity has increasingly become a global concern. Food adulteration， fraudulent substitution， and other practices constitutes food authenticity issues， particularly prominent in high value-added products. Food adulteration not only seriously harms consumers’ interests， but also brings negative effects by eroding their trust in the food industry， thereby hindering its development. To ensure food authenticity and safety throughout the entire production process， this study analyzed the authenticity of food production， reviewed its background and definition， domestic and global concerns， and China’s current management on food authenticity management. Then general technical specifications for food authenticity control and management were proposed， in order that the entire production chain meets the requirements. It aims to build a scientific， reasonable， and efficient food production safety management system to reduce the occurrence of food safety incidents， hoping to provide reference for the developing of technical specifications on certain food production authenticity control and management.

Abstract:Objective To determine the molecular characteristics of the outbreak associated Clostridium perfringens， and to contribute to improved future outbreak management.Methods Real-time fluorescence polymerase chain reaction （RT-PCR） was used for rapid screening of samples. Conventional bacterial isolation was performed on RT-PCR positive samples， and mass spectrometry analysis， and biochemical identification were conducted for identification. Virulence genes detection， antimicrobial susceptibility testing were conducted on confirmed C. perfringens isolates. Molecular typing was carried out using pulsed field gel electrophoresis （PFGE）.Results C. perfringens was detected in 10 rectal swabs and 1 food sample （barbecued meat）. All 11 C. perfringens were positive for virulence gene detection， with 9 isolates being cpa+/cpe+ and 2 being cpa+/cpe-. PFGE-based cluster analysis identified two PFGE patterns. One isolate from the barbecued meat and eight from the rectal swabs belonged to the same pattern which were identical， while two other isolates from another pattern showed a similarity of 94.7%. While all isolates were sensitive against piperacillin， ceftriaxone， imipenem， penicillin， clindamycin， and chloramphenicol， three isolates demonstrated resistance against metronidazole.Conclusion Based on clinical symptoms， epidemiological investigation， and laboratory testing， it is suggested that this foodborne disease outbreak was caused by Clostridium perfringens. Enhanced surveillance of Clostridium perfringens is needed to monitor the emergence and dissemination of antimicrobial resistance in this species.

Abstract:Objective To identify the suspicious food， etiologic agent， and risk factors of a foodborne disease outbreak in a middle school in Nanjing， and to examine issues identified during the investigation， thereby providing evidence to inform the prevention， control， and investigation of similar incidents in the future.Methods Field epidemiological investigations were conducted to identify the suspected meal and food items. On-site sanitary investigations were performed to determine the contamination points， and laboratory testing was undertaken to confirm the etiologic agent. Samples detected positive for Clostridium perfringens through PCR-based multi-pathogen screening were subjected to C. perfringens isolation. The obtained isolates were analyzed by whole-genome sequencing （WGS）， followed by downstream bioinformatic analyses including virulence gene profiling and phylogenetic analysis.Results Totally 56 suspected cases with diarrhea and abdominal pain were identified， among them a few cases exhibiting nausea and vomiting. The epidemic curve was consistent with a point source exposure pattern， with an incubation period of 2-14 h. Analytical epidemiological investigation identified the Chinese cabbage （“xiaobaicai”） served at dinner on August 14^th as the suspected food item. C. perfringens was detected in 30 anal swab samples， one food sample， and one environmental sample. Specifically， the concentration level of C. perfringens in the dinner sample of Chinese cabbage on August 14^th was 3.2×10⁵ CFU/g. WGS revealed that isolates from 10 cases， 8 employees， and one food sample （Chinese cabbage） all belonged to the same ST734 Lineage 1 clade， and harbored the cpe virulence gene. Core-genome SNP analysis showed 0-2 SNP differences， indicating high genetic relatedness.Conclusion Based on on-site investigation and traceback analysis， this outbreak was attributed to the consumption of Chinese cabbage served for dinner in the school cafeteria， with C. perfringens as the etiologic agent. WGS proved valuable for precise tracing in foodborne disease outbreak investigation.

Abstract:Objective To systematically evaluate the toxic effects and potential health hazards of butyl benzyl phthalate （BBP）， thereby providing a scientific basis for its risk management and control.Methods Literature published in both Chinese and English before September 20， 2024， was retrieved from CNKI， Wanfang Data， PubMed， and Comparative Toxicogenomics Database（CTD）. The literature was evaluated for quality using established guidelines for assessing the reliability and relevance of toxicological data. Then the included literature was classified according to the type of toxicity examined. Finally， synthesis of the evidence was conducted through qualitative description. For human population studies， only those with complete data on health effects were included. Meta-analysis was conducted after literature quality assessment.Results Totally 142 literatures were included in experimental studies， which demonstrated that BBP exhibited multiple toxic effects， including hepatotoxicity， nephrotoxicity， reproductive and developmental toxicity （e.g.， reduced sperm quality， altered sex hormone levels， shortened anogenital distance）， neurotoxicity， and immunotoxicity. The no-observed-adverse-effect level （NOAEL） of BBP was determined to be 50 mg/kg body weight. For human studies， 24 literatures were included. Meta-analysis results showed no statistically significant associations between BBP exposure and the following outcomes， such as sperm concentration/motility/morphology in males， preterm birth and spontaneous preterm birth in females， attention deficit hyperactivity disorder （ADHD）， mental development index （MDI）， and psychomotor development index （PDI） in children， with the 95% confidence intervals （95% CI） of all pooled odds ratios （OR） included 1.Conclusion Experimental studies identified reproductive and developmental toxicity as the primary toxicological endpoints of BBP， yielding a tolerable daily intake （TDI） of 0.5 mg/kg body weight. Due to insufficient evidence from human studies to establish a clear significant impact of BBP on human health， further research is warranted.

Abstract:L-Ergothioneine （L-EGT） is a histidine-derived compound widely present in edible mushrooms， certain legumes， animal organ meats， which must be obtained through dietary intake as it can’t be synthesized by humans. This review aims to evaluate the safety and health benefits of L-EGT based on a systematic literature assessment. Safety evaluations indicated an acute oral LD?? >2 000 mg/（kg·BW）. In subchronic toxicity studies， the no-observed-adverse-effect level （NOAEL） was established at 800 mg/（kg·BW）， while subacute testing revealed no adverse effects even at the highest administered dose ［615-725 mg/（kg·BW）］. Additionally， all assessed genetic and reproductive/developmental toxicity endpoints were negative. Human studies have shown no adverse health effects associated with a daily L-EGT intake of up to 25 mg. In terms of health benefits， L-EGT exerts physiological effects primarily through antioxidant， anti-inflammatory， anti-apoptotic， autophagy-promoting， cognitive function improvement， metabolic disorders amelioration， and various organ injuries alleviation. Currently， L-EGT has been approved as a novel food ingredient in the EU and is regulated as a Generally Recognized as Safe （GRAS） substance in the US， while Japan and Canada also permit its use in foods or health products. In China， its application as a novel food ingredient was accepted for review in May 2024. In conclusion， based on available literature， L-EGT exhibits multiple health benefits at appropriate doses， indicating considerable potential for food applications. Future research should focus on long-term dietary safety and standardization of analytical methods to ensure its scientific-based application and regulation.