Abstract:Objective To utilize whole genome sequencing to comprehensively compare and analyze the genomic characteristics of Listeria monocytogenes （L. monocytogenes） and Listeria innocua （L. innocua） isolated from commercially available foods in Gansu Province.Methods During 2021 and 2022， 25 strains of L. monocytogenes and 7 strains of L. innocua were isolated from commercially available food sources within Gansu Province and subjected to whole genome sequencing for phylogenetic lineage， clonal complex （CC）， sequence type （ST）， virulence gene， resistance gene， and pan-genome analyses.Results The 32 Listeria strains examined could be classified into three distinct groups： L. monocytogenes lineages Ⅰ and Ⅱ and L. innocua. Considering their CC types， further subdivision into 10 subgroups was observed for L. monocytogenes， whereas L. innocua had 5 subgroups. Core genome multi-locus sequence typing effectively differentiated strains with different CC types within each lineage， with lineage Ⅰ showing a closer evolutionary relationship with L. innocua. All 25 L. monocytogenes strains carried Listeria pathogenicity island 1 （LIPI-1） and internalin genes； none carried LIPI-3， and 2 strains of ST87 carried LIPI-4. Conversely， none of the seven strains of L. innocua carried LIPI-1 or internalin genes； however， they all carried LIPI-4， and 5 carried LIPI-3. Among the L. monocytogenes strains， 16 carried surface sensory island 1 （SSI-1）， and 3 carried SSI-2； all 7 L. innocua strains did not carry SSI-1， but 6 of them carried SSI-2. The pan-genome size of L. monocytogenes increased linearly with the number of sequenced genomes. Upon reaching 15 strains， the number of core genes stabilized at 2 272， accounting for 46.2% of the pan-genome genes. Furthermore， 1 487 common core genes were shared between the 25 L. monocytogenes strains and 7 L. innocua strains， with the count tending to stabilize when the strain count reached 10.Conclusion Multi-locus sequence typing of the core genome can effectively distinguish among Listeria strains originating from different lineages and CCs. The similarity in the biochemical characteristics of L. monocytogenes and L. innocua is due to their close genetic relationship， while the differences in their pathogenicity can be attributed to the presence of certain virulence genes in L. monocytogenes.

Abstract:Objective The pathogenic potential of Shiga toxin-producing Escherichia coli （STEC） isolated from different sources in China was classified to provide reference for risk management of STEC.Methods This study used hazard classification method，porposed by the Food and Agriculture Organization of the United Nations and the World Health Organization’s report， what name is Shiga toxin-producing Escherichia coli （STEC） and food： attribution， characterization and monitoring. We used to classify and analyze the published STEC data in China from 2018 to 2022.Results STEC isolates were classified as low-risk （72.9%）， high-hazard （26.0%） and highest-hazard （1.1%） strains. The high-hazard strains were mainly from cattle or beef food （95.3%）， only 8 highest hazard strains were from cattle and patients.Conclusion The serotypes of STEC strains are not enough to evaluate the virulence of STEC strains. The virulence gene combination is a more reliable method to classify the risk of STEC infection. This method could provide reference for STEC surveillance and risk assessment in China.

Abstract:Objective To study the effects of different heat treatments on milk digestion in vitro.Methods The dynamic human stomach-intestine Ⅳ+ was used to analyze the pH change， protein digestibility， gastric emptying and peptide distribution of four different heat-treated milk products： raw milk， pasteurized milk， ultra-high-temperature sterilized （UHT） milk and direct steam infusion （INF） milk.Results The pH change trends of raw milk and pasteurized milk in the stomach were very similar. Pasteurized milk took the shortest time to digest into a near-fasting state in the stomach. The protein digestibility of pasteurized milk was also the highest， whereas that of UHT milk was significantly lower than the other three samples. The molecular weight of peptides generated by the four kinds of milk after in vitro gastric digestion was below 5 000 u. After in vitro gastrointestinal digestion， the molecular weight of the peptides reached below 1 000 u， which is easy for digestion and absorption by the human body. Pasteurized milk and INF milk have advantages in protein digestibility and the molecular weight analysis of peptides of their digestion products. However， the general trend was the same without significant differences： they were both superior to UHT milk.Conclusion The in vitro digestion profiles of INF milk and pasteurized milk were the same， which were better than those of UHT milk， providing consumers with a new choice for dairy products.

Abstract:Objective To investigate the current status of microbial contamination in domestic freezers and evaluate the microbial improvement effects of professional refrigerator cleaning.Methods Samples were collected aseptically from the food dividers， vegetable frames， and door seals of 15 household refrigerators before and after cleaning in Chengdu City. A total of 90 samples were obtained. The total number of bacteria， fungi， and coliforms in the samples was determined to reflect the sanitary conditions of the refrigerator. Coliform bacteria， Staphylococcus aureus， Salmonella， Listeria monocytogenes and Yersinia enterocolitica were isolated and cultured to determine the contamination status of these pathogenic bacteria. The effect of refrigerator cleaning was analyzed comprehensively according to microorganism detection and clearance rates before and after cleaning.Results Before cleaning， the total number of bacteria in the refrigerator ranged from 2.4×10³ to 1.4×10⁵ CFU/cm². After cleaning， the total number of bacteria ranged from 0 to 230 CFU/cm². The bacterial clearance rates of the food dividers， vegetable frames， and door seals were 99.90%， 99.89%， and 99.81%， respectively. Before cleaning， the total number of fungi in the refrigerator ranged from 0 to 750 CFU/cm². After cleaning， the total number of fungi in the refrigerator ranged from 0 to 58 CFU/cm². The fungal clearance rates for the partition， vegetable frame， and door seal were 99.40%， 96.99%， and 99.41%， respectively. Before cleaning， the average detection rates of coliform bacteria， Staphylococcus aureus and Salmonella， were 64.44%， 13.33%， and 2.22%， respectively； Listeria monocytogenes and Yersinia enterocolitica were not detected. After washing， the average coliform bacteria detection rate was 13.33%； Staphylococcus aureus， Salmonella， Listeria monocytogenes， and Yersinia enterocolitica were not detected.Conclusion This study revealed the presence of a high number of bacteria and fungi in the freezers of domestic refrigerators before cleaning， with S. aureus and Salmonella contamination. After professional cleaning， their sterility significantly improved， notably reducing potential food safety risks.

Abstract:Objective To establish a rapid and accurate molecular method for detecting Clostridium perfringens （C. perfringens） in food using fluorescent multi-enzyme isothermal rapid amplification （MIRA）.Methods Primers and probes based on the conserved sequence of the C. perfringens alpha toxin-coding gene plc were designed separately， and the fluorescence MIRA method was established and optimized. The genomic DNA of 17 non-C.perfringens strains were extracted for specificity verification， and the isolated DNA and bacterial solutions of different dilutions were used for sensitivity evaluation. Matrix interference testing with 4 types of food media was also performed to evaluate the stability of the method， and the actual sample detection results were compared with the standard method to verify its practicality.Results The fluorescent MIRA method for C. perfringens used in this study had high specificity. The results returned negative for other non-C. perfringens strains. MIRA also had high sensitivity， with detection limits of 1.05×10¹ fg/μL for genomic DNA and 7.5×10⁰ CFU/mL for pure C. perfringens cultures. It also had a strong anti-interference ability； the detection results were not affected by the matrix， and the detection time was short （approximately 20 min）.Conclusion This study developed a rapid， accurate， sensitive and specific fluorescent MIRA method for the molecular detection of C. perfringens in food.

Abstract:Objective A TaqMan-based real-time fluorescence quantitative polymerase chain reaction （PCR） method was established to detect Clostridium perfringens （C. perfringens） in tap water samples.Methods The highly conserved plc gene located in the pseudonucleus of the bacterium was amplified and specific primers and TaqMan probes were designed. After optimization， a TaqMan-based real-time fluorescence quantitative PCR detection method was established. Combined with the filter membrane method， simulated polluted water samples of standard strains containing plc genes were treated， and the established method was tested.Results The established TaqMan-based method for detecting C. perfringens showed high specificity. Ct >40 were found in 13 foodborne pathogens， 3 Clostridium difficile and 1 Clostridium putrefaciens strain. The detection limit of this method was 1×10 copies/μL， showing high sensitivity. The minimum detection limit for the simulated polluted water sample was 1.0×10² CFU/mL. This method was also used to detect 4 simulated water contamination samples and 90 imported water samples. The results showed that C. perfringens could be detected in 2 simulated 1.0×10² CFU/mL-contaminated water samples， while not in 2 simulated 1.0×10 CFU/mL-contaminated and imported water samples.Conclusion The TaqMan real-time fluorescence quantitative PCR method established in this study for the detection of C. perfringens has good specificity， high sensitivity， and practical value for detecting C. perfringens in water samples.

Abstract:Objective To evaluate the exposure levels and health risks of aflatoxins （AFT） in dried chili and chili powder sold in Shandong Province.Methods AFT in chili and chili powder samples were determined using liquid chromatography-triple quadrupole mass spectrometry， and aflatoxin exposure was calculated using the point evaluation method.Results The detection rate of AFTB₁ was the highest in the 120 samples of dried chili and chili powder investigated， at 21.7% （26/120）. The proportion of samples exceeding the national standard limit was 8.3% （10/120）； the qualification rate was 91.7% （110/120）. The detection rate of AFTB₂ was 19.2% （23/120）， that of AFTG₁ was 5.0% （6/120）， and that of AFTG₂ was 0.8% （1/120）. The detection rate of AFT in chili powder was significantly higher than that of dry chili samples （P<0.05）. Daily dietary exposure to AFTB₁ accounted for 74.1% of the total daily dietary exposure to AFT. The incidence of liver cancer caused by dietary exposure to AFTB₁ was 0.001 09/100 000 people.Conclusion Relevant regulatory departments may strengthen the monitoring of aflatoxin pollution in the storage link of chili products， formulate targeted measures according to the temperatures and humidities in each region， maximize the control of aflatoxin pollution， and protect human health.

Abstract:Objective To investigate the infection of stage Ⅲ Anisakis spp. larvae in marine fish in five areas of Fujian Province.Methods Marine fish of different species were purchased from seafood markets from October 2021 to May 2022 and were directly dissected. The internal organs and muscles were artificially digested to identify stage Ⅲ Anisakis larvae， and the species were identified via light microscopy. The infection of Anisakis larvae was then analyzed by geographic area and species.Results A total of 133 marine fish from 18 species were dissected， with 68 fishes of 12 species being infected with Anisakis larvae； 2 214 larvae were detected. The detection rate， total infection rate and infection degree of Anisakis larvae were 66.7% （12/18）， 51.1% （68/133） and 32.6 larvae/tail （2 214/68）， respectively. Among the fish species， the infection rate of Trichiurus lepturus was 416 larvae/tail. The marine fish species in which Anisakis larvae were not detected were Acanthopagrus latus， Hypomesus olidus， Oriental grouper， cuttlefish， whitefish， and cream fish. According to regional distribution， the Changle area had the highest infection rate （66.7%）， while the highest detection rate of different marine fish varieties among the different areas was in Xiangcheng City （71.4%）.Conclusion The infection of stage Ⅲ Anisakis larvae in marine fish in the five areas of Fujian Province was serious. The distribution density of Anisakis larvae in marine fish and the detection rate of Anisakis larvae in each area were high. Hence， residents in these five areas of the Fujian Province have a high risk of infection.

Abstract:Objective To investigate the infection status， pathogenic types， antimicrobial resistance and molecular typing of diarrheagenic Escherichia coli （DEC） isolated from patients with foodborne diarrhea in Xi’an City in 2021.Methods Fecal samples from patients with diarrhea were collected from 5 sentinel hospitals for DEC isolation and the pathogenic types of DEC were confirmed via PCR to detect virulence genes. Antimicrobial susceptibility testing and molecular typing were performed using the broth microdilution method and pulsed field gel electrophoresis （PFGE）. The results were statistically analyzed using SPSS software 19.0.Results Among the 389 fecal samples collected from patients with diarrhea， 40 were DEC-positive， with a positivity rate of 10.28%. A total of 41 DEC strains were identified in this study. Enterotoxigenic E. coli （ETEC） and enteroaggregative E. coli （EAEC） were predominant， accounting for 41.46% （17/41） and 39.02% （16/41） of cases， respectively. The gene types estIa/estIb （70.59%， 12/17） and astA/pic （87.50 %， 14/16） were dominant in ETEC and EAEC， respectively. Forty strains （97.56%， 40/41） were resistant to at least one antibiotic， and the resistance rates to ampicillin， tetracycline， cefotaxime， and nalidixic acid were greater than 50%. The multidrug resistance rate was 56.10% （23/41）. Cluster analysis revealed 40 PFGE patterns from the 41 DEC strains. The similarity of these patterns was 62.0%-100.0%.Conclusion The detection rate of DEC in patients with foodborne diarrhea in Xi’an City in 2021 was relatively high， with the major pathotypes being ETEC and EAEC. The PFGE patterns of the strains were diverse. Finally， the antimicrobial and multidrug resistance of the strains was relatively severe.

Abstract:Objective To investigate the current status of allergen labeling in prepackaged food products in China.Methods A total of 986 prepackaged foods in 18 categories were from 26 provinces （autonomous regions， centrally administered municipalities） randomly selected from the nationwide market. The labeling type and accuracy were analyzed by collecting allergen labeling information and detecting allergens using ELISA.Results The overall allergen labeling rate was 44.7% （441/986）. Except for eight types of allergens， sesame had the highest prevalence （20.6%； 91/441）. Primary allergens were present in 61.9% （273/441） of samples. Most allergens were labeled below the ingredient list （76.4%， 337/441） and almost all allergens were not highlighted （93.4%， 412/441）. Approximately 80.3% （290/361） of surveyed samples accurately used “milk” allergen labeling， with 13.0% （47/361） of surveyed samples containing hidden allergens. Moreover， 6.6% （24/361） of surveyed samples showed allergen over-labeling.Conclusion The overall labeling of allergens in prepackaged food in China met the standard requirements. However， certain risks of hidden allergens and low accuracy of precautionary labeling were observed in certain products.

Abstract:Objective To compare the levels of contamination of seven mycotoxins， including deoxynivalenol （DON）， zearalenone（ZEN）， fumonisin B1（FB1）， tenuazonic acid（TeA）， alternariol monomethvl ether（AME）， T-2 Toxin（T-2）， ochratoxin A（OTA） in organic and conventional wheat flour sold in Shanghai City， and analyze the cumulative contamination of Fusarium toxin， Alternaria toxin and OTA.Methods Samples were extracted with acetonitrile， and the contents of the seven mycotoxins were detected using ultra-performance liquid chromatography-tandem mass spectrometry. The calibration curves for all mycotoxins were linear， with correlation coefficients above 0.99. The average recoveries of the spiked samples ranged from 80.13% to 122.86%， with relative standard deviations from 1.91% to 17.14%. This method is simple and rapid， with high accuracy and precision， and meets the requirements for mycotoxin analysis in flour.Results T-2 and FB1 were not detected in organic or conventional flours. The contamination levels of DON， ZEN， AME and OTA in organic flour were higher than those in conventional flour. The existence of at least two mycotoxins was observed in 97.5% of the flour samples， with DON+ZEN+OTA having the highest coexistence rate at 18.75%.Conclusion The rate and level of mycotoxin contamination in organic wheat flour were higher than those in conventional wheat flour. The cumulative contamination of Fusarium toxins （DON， ZEN）， Alternaria toxins （TeA， AME） and OTA were also observed.

Abstract:Recently， approximately 20% of the products unqualified in the national sampling inspection of imported food have been found through food label inspection， which has become one of the most important inspection methods for imported prepackaged food. In this study， the labels of imported prepackaged food were analyzed to determine the important inspection points， noting that particular attention should be paid to the conformity of products with the entry and registration requirements of the general administration of customs， the use of compliant raw materials， and the standardization of the special labeling content. The results suggest that the quality and efficiency of label inspection should be improved from four aspects： enhancing the awareness and ability to prevent and control unqualified risks， strengthening the training of inspectors’ professional skills， developing an artificial intelligence label verification system， and optimizing the relevant laws and standards to improve the safety of imported prepackaged food.

Abstract:Objective To provide a scientific basis for optimizing the registration and regulation， disease/medical states with a high clinical need for specific whole-nutrient foods for special medical purposes （FSMP-S） were identified.Methods A core outcome set construction method was used in this study. A systematic review was conducted to determine the list of diseases/medical states that could be supported by FSMP-S. Then， a list of diseases/medical states with high clinical demand for FSMP-S was selected through the Delphi method and face-to-face consensus meetings， and optimization suggestions for classifying the FSMP-S were proposed.Results A total of 27 studies were identified， and 103 diseases/medical states with FSMP-S intervention were obtained from 5，984 papers in Chinese and English. Forty-seven physicians and dietitians from 3A hospitals participated in two rounds of Delphi surveys， after which 23 diseases/medical states were recognized as having high clinical demand for FSMP-S. The consensus meeting narrowed the scope of the FSMP-S to a high clinical need of 11 diseases/medical states. Finally， a “1+1” optimization strategy was proposed to add nutritional metabolic characteristics to the classification method for FSMP-S.Conclusion The “1+1” strategy could optimize the classification of FSMP-S from the perspective of clinical application requirements； however， its feasibility remains undemonstrated.

Abstract:Objective To provide a reference for developing nutrition labels for fresh agricultural products， we explored consumers’ understanding of and willingness to consume fresh agricultural products with nutrition labels.Methods In total， 682 valid questionnaires were collected via online surveys. Descriptive statistics and logistic regression analyses were conducted to analyze consumers’ understanding of nutrition labels for fresh agricultural products， their willingness to consume them， and the underlying factors.Results E-commerce platforms are important channels for selling fresh agricultural products. The demand for pre-packaged and exquisitely packaged fresh agricultural products has increased gradually. More than 75% of consumers frequently check nutritional labels when purchasing food products. Approximately 88.9% of consumers expect nutrition labels for fresh agricultural products and pay attention to the nutritional claims， including the content of sugar， vitamins， minerals， phytochemicals， and other ingredients. Consumers prefer quantitative labeling of nutritional components and the format of nutrition fact tables. Significant differences （P<0.05） were observed in consumers’ willingness to consume fresh agricultural products with nutrition labels and to pay a premium based on different identities and monthly incomes. Overall， 88.56% and 91.94% of the consumers had varying degrees of willingness to consume and pay premiums for nutrition labels on fresh agricultural products， respectively.Conclusion This study indicates that consumers have a strong demand to understand the nutritional information of fresh agricultural products. They also expect to include nutrition labels for fresh agricultural products and are willing to pay premiums. Therefore， promoting the development and inclusion of nutritional labels for fresh agricultural products has practical significance and potential for the market.

Abstract:Objective To provide a scientific basis for the prevention and control of botulism， we analyzed the epidemic characteristics and influencing factors of foodborne botulism incidents in Qinghai Province over the years.Methods Botulism data from 1959 to 2022 were collected， and epidemiological characteristics were analyzed using Microsoft Excel 2021 software. The Mann-Kendall trend test was conducted to analyze the number of botulism events and case fatality rates using R 4.2.3 software. The ArcGis 10.2 software was used to create a spatial distribution map of botulism incidents in Qinghai Province.Results A total of 86 events of foodborne botulism occurred from 1959 to 2022， with 348 cases and 195 deaths. The case fatality rate was 56.03%. The incidence was mainly concentrated in the second and third quarters， with herders being the major affected population. The chief type of botulinum toxin was the E type and “air-dried meat” was the major toxic food source. Raw and ready-to-eat foods were the major products consumed.Conclusion As a region with a high incidence of foodborne botulism， the cases of botulism and fatality rates have decreased significantly from 1959 to 2022. However， the case fatality rate remains high. Considering the particularity and high case fatality rate and geographical location of botulism， food safety education must be strengthened for high-risk groups， attract the attention of grassroots personnel in high-incidence areas， and improve the ability of grassroots medical institutions to treat this disease.

Abstract:Objective To analyze the epidemiological characteristics of tetrodotoxin poisoning events in China from 2011 to 2020 and provide a scientific basis for precise measures to prevent and control tetrodotoxin poisoning.Methods Descriptive epidemiological methods were used to analyze the epidemiological characteristics of tetrodotoxin poisoning incidents reported through the National Foodborne Disease Outbreak Monitoring System from 2011 to 2020.Results From 2011 to 2020， 92 cases of tetrodotoxin poisoning reports were received through the National Foodborne Disease Outbreak Monitoring System； 339 people were poisoned and 15 were dead， with a case fatality rate of 4.4%. Tetrodotoxin poisoning was mainly concentrated in the coastal areas of China. The food carriers of tetrodotoxin included pufferfish （71.7%， 66/92）， dried pufferfish （13.0%， 12/92）， Nassariidae （7.6%， 7/92）， horseshoe crabs （5.4%， 5/92）， and Acentrogobius nebulosus （2.2%， 2/92）. Each year， a high incidence of poisoning occurs from March to April.Conclusion To effectively prevent and control tetrodotoxin poisoning， it is necessary to establish a method for detecting tetrodotoxins in biological samples， improve the ability to identify the pathogenic factors of tetrodotoxin poisoning， strengthen the supervision and popularization of science in the circulation process， and change the dietary habits of people who eat wild pufferfish.

Abstract:Hepatitis E virus （HEV） is a universal foodborne pathogen that infects swine， deer， rabbits， camels， and other animals. Direct contact with infected pigs and other animals or consumption of contaminated food （uncooked or undercooked） poses a risk of HEV infection in humans. This article summarizes the etiology and epidemiology of HEV， its prevalence in various animal species， and the contamination of meat and meat products， the aquatic environment， seafood， vegetables， and other crops. Therefore， people can better understand the risk of foodborne HEV transmission and provide a scientific basis for preventing and controlling its prevalence.

Abstract:Gold nanoparticles （GNPs） have good biocompatibility and unique optical properties， and their surfaces can be combined with biological and organic molecules to form functionalized GNPs. Owing to these characteristics， GNPs have a wide range of applications in food safety detection. This article reviews the application of GNPs for the detection of food-borne pathogens， biotoxins， heavy metal ions， drug residues， food additives， illegal additives， and other harmful food factors. Moreover， prospects for the application of GNPs in food safety detection are also discussed.

Abstract:Recently， the analysis of animal- and plant-derived components， mainly based on the adulteration and smuggling of meat products and genetically modified crops， has been a key focus in the field of food safety. Therefore， the requirement for analytical methods has been increasingly emphasized. Recombinase isothermal amplification is a novel and promising detection technique that currently includes recombinase polymerase amplification （RPA） and recombinase-aided amplification （RAA）. This technique has been widely used in animal- and plant-derived component analysis and other detection and analysis fields owing to its speed， convenience， and high sensitivity and specificity. This paper summarizes relevant research conducted locally and abroad in recent years and concludes with an analysis of various detection methods. It also generalizes the characteristics and applications of RPA/RAA technology in four aspects： primer-probe design， external factors， reaction devices， and detection methods， and lays out the prospects for RPA/RAA development trends. Finally， this study also provides a reference for improving the analysis and detection methods of animal- and plant-derived components and promoting RPA/RAA technology.