Abstract:Objective To study the distribution characteristics of carbapenem-resistant bacteria in aquatic products in Shanghai markets and antibiotic resistant genes profiles.Methods Carbapenem-resistant bacteria in aquatic products were isolated using TCBS and TSA plate containing antibiotics （meropenem）. The bacteria was identified using matrix assisted laser desorption/ionization time of flight mass（MALDI-TOF MS） spectrometry. The antimicrobial susceptibility was investigated using minimum inhibitory concentration （MIC）. Some antibiotic resistant bacteria were analyzed using whole-genome sequencing. BioNumerics software was used to analyze and assemble whole-genome sequencing data， which was used to analyze antibiotic resistant genes profiles.Results The positive rate of carbapenem-resistant bacteria in aquatic products in Shanghai was high （75.0%~90.5%）. The prevalent bacteria was Stenotrophomonas maltophilia， followed by Pseudomosa spp.， Aeromonas spp. and enterococcus spp. The multi-drug resistance was serious. The antibiotics with higher resistance rate were cephalosporins， tetracycline and ampicillin. A total of 64 antibiotic resistant genes were detected. The carbapenemase-encoding genes were bla_NDM-1， bla_OXA55 and bla_OXA280 in this study.Conclusion The carbapenem-resistant bacteria in aquatic products in Shanghai markets was widespread. Multi-drug resistance was serious. Furthermore， the antibiotic resistant genes profiles showed diversity， which might be mechanism of occurrence of resistance. These results suggested that surveillance of resistant bacteria and antibiotic resistant genes profiles should be strengthened， which would provide scientific data for food safety risk assessment.

Abstract:Objective To explore the whole-genome characteristics of methicillin-resistant Staphylococcus aureus （MRSA）.Methods Four ST9 MRSA strains isolated from pig carcasses and slaughter workers were collected and sequenced. The genetic characteristics， resistance genes and virulence genes of their genomes were analyzed. Single nucleotide polymorphism（SNPs） were screened by comparative genomics， and the comparisons with the core genes of 11 MRSA and methicillin sensitive Staphylococcus aureus（MSSA） with different ST type from NCBI were analyzed to construct a phylogenetic tree.Results The results showed that the full-length genomic sequence of the four ST9 MRSA strains from different sources was about 2.6 Mbp， of which contained 2 122-2 494 genes， and the average GC content of the genes in the four genomes was 32.8%. The genomes from different sources contained 26-31 drug resistance genes and 44-56 virulence genes. Compared with ST398 MRSA which was popular in Europe and other countries， the four ST9 MRSA strains had high nucleotide homology， and the numbers of SNPs between strains were less than 300. The phylogenetic tree analysis showed that ST9 and ST398 MRSA had been divided into different independent evolutionary branches in the molecular evolutionary courses. MRSA strains from animal and human origin had no obvious correlation in molecular evolution.Conclusion This study obtained background materials on the basic characteristics of the ST9 MRSA genome from different sources， which could help understand the molecular evolutionary traceability of different ST-type MRSAs. These data will provide scientific guidance for subsequent studies on the molecular epidemiology and pathogenic mechanism of ST9 MRSA.

Abstract:Objective After polymyxin was banned as growth promotion in animals， the carrying status of mcr-1 gene of Escherichia coli（E.coli） in chickens in some areas of Sichuan Province was investigated to provide basis for further prevention and control measures.Methods Rectal swabs were collected from broilers in some markets in Sichuan Province. The bacteria were inoculated with E.coli broth containing polymyxin （final concentration 4 μg/mL） and macconkey plate containing polymyxin （final concentration 4 μg/mL）. Suspicious colonies were selected and identified by PCR and mcr-1 gene was detected. Microbroth dilution method was used to determine the resistance of mcr-1 gene positive strains to common antibiotics. Pulse field gel electrophoresis （PFGE） was used to analyze the homology of mcr-1 gene positive strains. mcr-1 gene transmission route was verified by plasmid binding assay.Results mcr-1 positive Escherichia coli was detected in 13 samples of 70 broiler chickens， with a detection rate of 18.57% （13/70）. Among the 13 antibiotics tested， 13 mcr-1 positive strains showed different degrees of drug resistance to antibiotics， except that 12 strains were sensitive to cefoxitin. The drug resistance rates of tetracycline and trimethoprim/sulfamethoxazole were the highest， reaching 100% （13/13）. Ampicillin and chloramphenicol followed with resistance rate of 84.62% （11/13）. PFGE showed that 13 mcr-1 positive Escherichia coli strains belonged to 13 different types. Plasmid binding experiments showed that mcr-1 gene could be transmitted through plasmids.Conclusion The detection rate of mcr-1 gene in chicken E.coli is high， and the drug resistance of mcr-1 positive E.coli in chicken is serious.

Abstract:Objective To better understand the epidemiology of this MDR clone and its potential for international spreading， the epidemiological characteristics and antibiotic resistance of Salmonella enterica serovar typhimurium （S. typhimurium） and monophasic variant 1，4，［5］，12∶i∶- （S.1，4，［5］，12∶i∶-） in Guangxi Zhuang Autonomous Region in 2021 were investigated.Methods Two hundred and seventy six strains of Salmonella from clinic samples were serotyped according to the Kauffmann White scheme by slide agglutination. A strain was confirmed as monophasic by multiplex PCR when phase-2 flagellar antigen was negtive after three times phase inversion. The strains were tested for antimicrobial susceptibility by disk diffusion method.Results Two hundred and one （72.8%） isolates of monophasic S. typhimurium and 75 isolates of S. typhimurium were identified by a specific multiplex polymerase chain reaction. Resistances to trimethoprim/sulfamethoxazole and chloramphenicol in S. typhimurium were higher than monophasic S. typhimurium significantly （P<0.05）. Resistances to ampicillin， cefotaxime， nalidixic acid， gentamicin and tetracycline in monophasic S. typhimurium were higher than S. typhimurium significantly （P<0.05）. Two serotypes of S. typhimurium were found to be resistant to over 79% of three classes or more antimicrobial agents. The common multiple dominant drug resistance spectrum was ampicillin， chloramphenicol， trimethoprim/sulfamethoxazole and tetracycline pattern.Conclusion Monophasic Salmonella typhimurium had replaced S. typhimurium as predominant serotype in diarrhea patients in Guangxi. The drug resistance of two serotypes Salmonella was not optimistic， especially the rapid increaseof multi-drug resistance isolates. Targeted efforts is needed to enhance foodborne S. typhimurium and monophasic S. typhimurium surveillance， which can reveal the underlying determinants of resistance in different microorganisms， and measure the effectiveness of interventions.

Abstract:Objective To study the effect of ethanol extract of propolis （EEP） and exercise on the immune function of obese people after exercise.Methods One hundred men were randomly assigned to the EEP group （n=50） and the placebo group （n=50）. The subjects in both groups exercised on a treadmill at an exercise intensity of 65% VO_2max. They exercised for 1 h a day and 5 times a week for 8 weeks. Participants in the EEP group took 1 EEP capsule （containing 100 mg EEP） once a day， and participants in the placebo group took 1 capsule that looked similar to the EEP capsule every day， which continued for 8 weeks. Then the NK cell activity， inflammatory factors ［（tumor necrosis factor-α （TNF-α）， interleukin-1β （IL-1β） and IL-10）］ levels and the proportion of lymphocytes （T cells， B cells and NK cells） were detected.Results Compared with the placebo group， the NK cell activity of the EEP group significantly increased （50.14%±8.86% vs 55.73%±7.85%， P=0.011）. Compared with the placebo group， serum TNF-α （893.46±177.32 pg/mL vs 637.53±152.35 pg/mL， P=0.014） and IL-1β （122.14±18.57 pg/mL vs 99.95±16.46 pg/mL， P<0.001） levels of the EEP group decreased significantly， and IL-10 （7.16±1.58 pg/mL vs 10.45±1.78 pg/mL， P=0.008） increased significantly. There was no significant change in the percentages of T cells， B cells and NK cells at baseline and after 8 weeks in the two groups （P>0.05）.Conclusion Taking EEP during exercise can help stimulate the activation of NK cells by improving the immune function.

Abstract:Objective To evaluate the effect of sulforaphane （SFN） on skeletal muscle damage and fatigue in mice induced by exhaustive exercise （EE）.Methods Sixty male Kunming mice were randomly divided into control group （Control）， exhaustive exercise group （EE）， SFN low-dose group （SFN-L， 20 mg/kg/d）， SFN medium-dose group （SFN-M， 40 mg/kg/d） and SFN high-dose group （SFN-H， 60 mg/kg/d）， each group was 12 animals. After total of 4 weeks of administration， the exhaustive exercise was done. The levels of creatine kinase （CK）， lactate （LA）， lactate dehydrogenase （LDH）， malondialdehyde （MDA）， superoxide dismutase （SOD） and catalase （CAT） in each group were determined. Histopathological changes were observed by hematoxylin-eosin staining. The ultrastructure of mitochondria was observed by transmission electron microscope. Energy levels were assessed by measuring citrate synthase （CS）， succinate dehydrogenase （SDH）， and liver and quadriceps glycogen content. RT-qPCR and Western blot were used to detect mRNA and protein expression levels related to mitochondrial autophagy in skeletal muscle.Results Compared with the EE group， the levels of CK， LA， LDH and MDA in the SFN-L， SFN-M and SFN-H groups reduced significantly， while the SOD and CAT activities increased significantly （P<0.05）. SFN significantly reduced skeletal muscle damage in EE mice and mitochondrial morphology was improved. Compared with the EE group， the liver glycogen and muscle glycogen content， CS expression and SDH activity in the SFN-L， SFN-M and SFN-H groups increased significantly （P<0.05）. Compared with the EE group， the protein expression levels of PINK1， Parkin， Lc3-Ⅱ， p62 and ubiquitin in the quadriceps femoris tissue of the SFN-L， SFN-M and SFN-H groups reduced significantly （P<0.05）. Compared with the EE group， the mRNA expression levels of PINK1 and Parkin in the quadriceps femoris tissues of mice in the SFN-L， SFN-M and SFN-H groups reduced significantly （P<0.05）.Conclusion SFN exerts anti-fatigue effects through inhibiting mitochondrial autophagy mediated by PINK1/Parkin signaling pathway.

Abstract:Objective To provide reliable technical support for the prevention and control of foodborne diseases and improve the ability to deal with food poisoning emergencies， the epidemic characteristics of Vibrio parahaemolyticus（VP）in Liaoning Province was studied.Methods The PFGE molecular typing， serological typing and drug sensitivity test of VP isolated from patients and food in 14 cities of Liaoning Province in 2020 were carried out and analyzed.Results Among the 44 strains of VP （22 isolates from foodborne diseases and 22 isolates from food）， 8 strains could not be identified with K-type， and the untyping rate was 18.2%. The other strains were divided into 15 serotypes and 9 serogroups. The isolates from foodborne diseases were divided into 4 serotypes and 3 serogroups. The main serogroup was O3， followed by O1. Foodborne isolates were divided into 11 serotypes and 6 serogroups. The main serogroup was O2， followed by O1 and O3. The results of drug sensitivity of 44 strains of VP to 15 antibiotics showed that the resistance rate of cefazolin was 68.2%， followed by ampicillin（22.7%）， erythromycin（13.6%）， azithromycin（4.5%）， cefoxitin（2.3%） and cefotaxime（2.3%）. The main strains were resistant to β-lactamand macrolide antibiotics. Drug resistance ability increased year by year， some strains showed multiple drug resistance， and the number increased year by year. The drug resistance rate of foodborne disease isolates was higher than that of food isolates. The drug resistance rate of the main epidemic strains with serotype O3：K6 was high. PFGE molecular typing could be divided into five PFGE dominant bands according to the similarity of more than 90%. VP isolated from the patients had high similarity and could be clustered into 3 groups. The similarity of VP isolated from food was low. Except that the similarity of two strains was greater than 90%， the similarity between other strains was less than 85%.Conclusion There was a high homology between O3 and O1 serotype strains， suggesting that O3 and O1 serotype strains were closely related. The homology between food strains was low， suggesting low correlation. The drug resistance of VP isolates in Liaoning Province in 2020 was not optimistic， and the drug resistance trend needed further attention.

Abstract:Objective To analyze the serotype characteristics， epidemiological characteristics and trend of antibiotic resistance of reported cases of Salmonella in Wuxi City， Jiangsu Province from 2017 to 2020.Methods Two hundred and sixteen Salmonella strains isolated from specimens of diarrhea cases （inpatient and outpatient） in Wuxi Foodborne Disease Sentinel Surveillance Hospital from 2017 to 2020 were collected， and the serotype identification and analysis of 216 strains were performed by the slide agglutination method. A micro broth dilution method was used to detect the drug susceptibility of Salmonella to 13 kinds of antibiotics.Results The 216 strains of Salmonella were divided into 42 serotypes. There were two dominant serotypes. Sixty two cases of Salmonella enteritidis accounted for 28.70%， and 57 cases of Salmonella typhimurium accounted for 26.39%. The results of drug resistance analysis showed that 216 strains of Salmonella were highly sensitive to meropenem， amikacin， azithromycin and ceftazidime， and the proportion of highly sensitive strains was higher than 90%； all Salmonella had the highest resistance rate to ampicillin， reaching 68.06%. The resistance rate to meropenem was the lowest， only 0.46%. The resistance rate of Salmonella to ampicillin increased year by year from 2017 to 2020， and resistance to ampicillinthe was the highest each year. A total of 130 strains had developed multi-drug resistance （60.19%）. The spectrum with the largest number of drug-resistant strains was AMP-TET-STR， accounting for 5.56% （12/216）， and the dominant drug resistance spectrum was not obvious.Conclusion The prevalent serotypes of Salmonella in Wuxi City were mainly enteritidis and typhimurium， and the drug resistance of Salmonella was severe. An efficient control mechanism should be established as soon as possible， drug sensitivity monitoring should be strengthened， treatment plans should be optimized， and antibiotic abuse should be avoided.

Abstract:Objective To study the management mode of recycled plastics in food contact materials in the United States， European Union， Japan， the Republic of Korea and other countries and regions， their practices were analyzed， and suggestions on the establishment of corresponding management measures in China were put forward.Methods The laws， regulations and guidance from different countries and regions on recycled plastics in food contact materials was collected. The management mode on recycled plastics in food contact materials was analyzed and compared from 4 aspects： management organization and responsibilities， management overview and approval procedures， safety assessment methods and current work progress. The content which could be used for reference in China was analyzed through comparison of the similarities and differences.Results Major developed countries and regions have established relatively mature management measures for recycled plastics in food contact， and carried out targeted management and control based on risk assessment.Conclusion It is suggested that China should draw lessons from the experience of Europe and the United States， further find out the current situation of the industry， carry out systematic safety assessment and research， and explore and establish risk management measures which are suitable for local conditions.

Abstract:Objective To investigate the potential mechanism of astaxanthin and/or aerobic exercise in relieving D-galactose-induced myocardial aging in rats.Methods Forty SD male rats aged 3 months were randomly divided into five groups， with 8 rats in each group： control group （group C）， aging model group （group D）， aging + astaxanthin group （group DA）， aging + aerobic exercise group （group DE） and aging + astaxanthin + aerobic exercise group （group DAE） .There was no intervention for group C. The other four groups were intraperitoneally injected with 100 mg/kg·d D-galactose. Group DA， DE and DAE were treated with 20 mg/kg·d astaxanthin and/or aerobic exercise at 60% VO₂ max， respectively. The experiment lasted for 6 weeks. Twelve hours after the last training， the rats were sacrificed for heart harvesting. The morphology of the heart tissue was observed under light microscope and the related biochemical indicators were measured.Results The morphology of myocardium in group C was normal. Compared with group C， the myocardial cell in group D showed disorder， fiber rupture and inflammatory cell infiltration. Compared with group D， groups DA， DE and DAE showed improvement， including orderly arrangement of myocardial cells， relieved myocardial fiber rupture and reduction of inflammatory cells， especially in group DAE. and the morphology of myocardial tissue in group DAE was much closer to normal. Compared with group C， the activity of superoxide dismutase （SOD）， γ-glutamate cysteine synthase （γ-GCs） and the expression of sirtuin 1 （SIRT1）， nuclear factor erythroid 2-related factor 2 （Nrf2）， heme oxygenase-1 （HO-1） and B-cell lymphoma-2 （Bcl-2） in myocardium and the ratio of Bcl-2/Bcl-2-associated X （Bax） of group D decreased significantly （P<0.05 or P<0.01）； the apoptosis level， the expression of Bax and the malondialdehyde （MDA） content increased （P<0.05 or P<0.01）. Compared with group D， the expressions of SIRT1， Nrf2 and HO-1 in group DA increased significantly （P<0.05）， while the expression of Bax and the MDA content decreased significantly （P<0.05 or P<0.01）. The activity of SOD and the expressions of SIRT1， HO-1 in group DE increased significantly （P<0.05 or P<0.01）， while the expression of Bax and the MDA content decreased significantly （P<0.05 or P<0.01）. The activity of SOD， γ-GCs， the expressions of SIRT1， Nrf2， HO-1， Bcl-2 and the ratio of Bcl-2/Bax in group DAE increased significantly （P<0.05 or P<0.01）； the apoptosis level， the expression of Bax and the MDA content decreased significantly （P<0.01）. Compared with group DA and DE， the expression of SIRT1， Bcl-2 and the ratio of Bcl-2/Bax in group DAE were increased significantly （P<0.05 or P<0.01）， and the apoptosis level decreased significantly （P<0.05）. Astaxanthin and aerobic exercise had synergistic effect on the apoptosis level， the expression of SIRT1， Bcl-2 and the ratio of Bcl-2/Bax in myocardium.Conclusion Astaxanthin and/or aerobic exercise intervention can alleviate and improve D-galactose-induced oxidative stress， which is achieved by increasing the expression of proteins related to the SIRT1/Nrf2 signaling pathway. It can also reduce the level of cardiomyocyte apoptosis and delay the myocardial aging of rats.

Abstract:Objective To investigate the changes of volatile flavor components in Longxi cured mutton during the four stages of raw material， curing， cooking and autoclaving.Methods Longxi cured mutton was studied by electronic nose and solid phase microextraction-gas chromatography-mass spectrometry （SPME-GC-MS） combined with relative odor activity value （ROAV） method.Results A total of 74 volatile flavor components were detected in Longxi cured mutton at different processing stages， with the number of species at each stage being 34， 26， 37 and 38 respectively， and the peak area ratio increased and then decreased. The curing and cooking stages were important processing stages affecting the flavor of cured mutton. ROAV analysis yielded 23 key flavor substances， with aldehydes contributing the most to the flavor formation of cured mutton， followed by hydrocarbons. 1-octen-3-ol， hexanal and nonanal were the characteristic flavor components of cured mutton. Overall， the volatile flavor components in the processing of Longxi cured mutton varied significantly during the curing and cooking periods， and aldehydes， hydrocarbons and alcohols were the main volatile species.Conclusion The experiment yielded changes in the volatile flavor components of Longxi cured mutton during processing， which could promote the development of Longxi cured mutton in modern industry regarding flavor control technology and accelerate its quality improvement and industrialization process.

Abstract:Objective To establish a rapid screening method for 85 toxic alkaloids in plasma samples using ultra-high performance liquid chromatography coupled with quadrupole/exactive high resolution mass spectrometry （UHPLC-Q/Exactive）.Methods A high resolution mass spectrometry compound database （CDB） of 85 alkaloids was established by UHPLC-Q/Exactive. Acetonitrile was used for protein precipitation as pretreatment in plasma samples. An Acquity Waters BEH C₁₈ column （100 mm×2.1 mm， 1.7 μm） was applied for gradient elution with 5 mmol/L ammonium formate （containing 0.1% formic acid） and acetonitrile as mobile phases. The screening accuracy of 85 toxic alkaloids in spiked plasma samples was compared in three data collection modes （Full mass/dd-MS²， Full mass/AIF and Full mass/DIA）.Results The screening accuracy of Full mass/DIA was the highest when plasma samples were added at three concentration levels of 5， 50 and 250 ng/mL. Combined with the CDB， a rapid screening method for 85 toxic alkaloids in plasma samples was established under the Full mass/DIA data acquisition mode. The limits of detection of more than 80% of the alkaloids in plasma samples were lower than 10 ng/mL. With this method， the target substance-yunaconitine and its possible metabolites， 3-deoxyaconitine and indaconitine were successfully screened in the 3 Wistar rat plasma samples obtained from the yunaconitine toxicokinetics experiment.Conclusion The method is fast， efficient， and suitable for the rapid screening of 85 toxic alkaloids in acute toxic alkaloid poisoned plasma samples with the absence of standard substances.

Abstract:Objective A fast confirmation method was developed for the determination of five nitroimidazoles drug residues in animal-derived foods by ultraperformance liquid chromatography-triple quadrupole/linear ion trap mass spectrometry coupled with solid phase extraction.Methods The samples were extracted with 1% formic acid-acetonitrile and then centrifuged. The supernatant was directly purified by solid phase extraction based on PRIME HLB cartridge， and then determined by ultraperformance liquid chromatography-triple quadrupole/linear ion trap mass spectrometry. The purification condition， mobile phase and chromatographic column were optimized. Under the optimal conditions， the sample was purified by prime HLB column and analyzed by BEH C₁₈ column with 0.1% formic acid- water and acetonitrile as mobile phase. The five nitroimidazoles were detected with positive electrospray ionization tandem mass spectrometry in the multiple reaction monitoring-information-dependent acquisition-enhanced product ion （MRM-IDA-EPI） mode， and quantified by isotopically labeled internal standard.Results The limits of quantitation were from 0.30 to 0.80 μg/kg. The average recovery rates of the 5 nitroimidazoles were 73.2%-115.2% with relative standard deviations of 3.2%-9.3% （n=6）.Conclusion The developed method is rapid， sensitive， accurate and suitable for the detection of nitroimidazole residues in animal-derived foods. The method can be used for screening and confirmation of samples in large quantities.

Abstract:Objective To genetically subtype staphylococcal enterotoxins by applying VFDB annotation method and evaluate its accuracy.Methods VFDB annotation method and enterotoxin gene-specific PCR were applied to genetically subtype 18 staphylococcal enterotoxins （including traditional enterotoxin genes sea-see， new enterotoxin genes seg-sej and enterotoxin-like genes sek-seu） in 53 Staphylococcus aureus isolated from food in Beijing from 2009 to 2016. All the enterotoxin gene sequences obtained by VFDB annotation method were uploaded to NCBI platform and further verified by BLASTX program and refseq_protein database.Results Among the 53 Staphylococcus aureus isolates， 45 isolates （84.91%， 45/53） were identified to have one or more enterotoxin genes， and 8 isolates were without enterotoxin genes by both VFDB annotation method and gene-specific PCR. The traditional enterotoxin genes were found in 31 isolates （58.49%， 31/53）. Among the 45 isolates which carried enterotoxin genes， 16 isolates （35.56%， 16/45） had consistent enterotoxin gene typing results， and 29 isolates （64.44%， 29/45） had inconsistent results between VFDB annotation methods and PCR method. Compared with BLASTX verified results， genotypes that could be misclassified by VFDB annotation method included sea/sed， sea/sej， sea/sep， sea/ser， seg/ser and sek/sei （VFDB annotation/BLASTX verification）.Conclusion VFDB annotation could be applied as an optional method in predicting staphylococcal enterotoxin genes， but the sequence annotated as sea， seg and sek need to be further verified by BLASTX and refseq_protein database to improve the accuracy.

Abstract:Objective To establish an efficient analytical method for simultaneous determination of 11 N-nitrosamines in Chinese pickles and salted vegetables by QuEChERS combined with gas chromatography-mass spectrometry.Methods The sample was extracted with acetonitrile， dehydrated by 4 g anhydrous magnesium sulfate and 1 g sodium chloride， purified with 150 mg PSA， 150 mg GCB and 900 mg anhydrous magnesium sulfate， separated by HP-Innowax chromatographic column， and quantitatively analyzed in the multi-reaction monitoring mode. The matrix effect was evaluated by calculating the ratio of the slope between the matrix and the solvent standard curve.Results In the range of 0.5-50 μg/L， the linear coefficient of 11 N-nitrosamines were all above 0.999. NDBA， NMPhA， NEPhA and NDPhA showed stronger matrix effects， and the standard solution should be prepared by the blank matrix solution. The average recovery rate of low， medium and high levels （1， 3， 10 μg/kg） in the sample spiking with reference standard was 94.8%-105.1%， of which the RSD （n=6） was 1.6%-5.8%.Conclusion With simple pretreatment operation， good reproducibility and accurate results， this method is suitable for the quantitative analysis of 11 N-nitrosamines in Chinese pickles and salted vegetables.

Abstract:Objective To develop a bacteria-containing cotton swab which is applied to the proficiency testing for coliform detection on sterilized tableware.Methods The positive sample contained both target bacteria and interfering bacteria， and the negative sample only contained interference bacteria. 10 bottles of negative and positive samples were selected randomly. The homogeneity tests were carried out in accordance with GB 14934—2016 Appendix B （Fermentation methed）. The samples were also stored for 120 d at -20 ℃ and 4 ℃， and 20-60 d at 25 ℃， 36 ℃ and 42 ℃respectively to monitor samples’ storage and transportation stability. Uniformity and stability testing results should be consistent with specific values. Three samples were delivered to each laboratory， and minimum of 1 positive sample was issued， the rest were randomly issued. In order to prevent data fabrication， sample numbers were randomly generated， and proficiency tests periods were shortened.Results The samples can meet the requirements of proficiency testing in terms of uniformity， storage stability and transportation stability. Fifty （91%） laboratories were qualified. Five （9%） laboratories were unqualified.Conclusion The proficiency test samples for the coliform detection on sterilized tableware can meet the requirements of proficiency testing. This proficiency test can truly reflect the testing environment and testing capability of the participating labortory.

Abstract:Objective To explore the current situation of pesticide residues in vegetables sold in Tianjin and the risks for Tianjin residents.Methods In accordance with the requirements of “The national food contaminants and harmful factors risk monitoring manual”， 516 representative vegetable samples were collected and tested. The exposure level and potential risk were evaluated by point evaluation method.Results Pesticide residues were detected in 364 of 516 （70.54%） vegetable samples. There were 244 of 516 （47.29%） vegetable samples with two or more pesticides at the same time. 31 of 516 （6.01%） vegetable pesticide residues exceeded the standard. The rank of violation rate was： Organic phosphorus pesticides>carbamate pesticides>pyrethroids pesticides>organochlorine pesticides>fungicide pesticides， which was significant different （χ²＝9.84， P<0.05）. The top three pesticides with the violation rate were phorate （2.62%， 10/381）， carbonfuran （1.55%， 8/516） and cypermethrin （0.90%， 2/223）. The results of acute exposure risk assessment showed that carbonfuran %ARfD was 238.89%， phorate %ARfD was 191.67%， greater than 100%， which was unacceptable. Chronic exposure risk assessment showed that IFS of all pesticide was less than 1 and the risk was acceptable.Conclusion The detection rate of pesticide residues in vegetable in Tianjin was high. Especially， combined use of multiple pesticides was prominent， and the use of banned pesticides still existed. Carbonfuran and phorate were risk factors in acute dietary exposure. The government and relevant departments should strengthen the supervision of pesticide residues in vegetables.

Abstract:Objective To investigate the pollution of heavy metals in chicken， eggs and chicken viscera in Anhui province， and to provide a basis for food safety risk monitoring and dietary guidance.Methods Chicken， eggs， chicken liver and gizzard were randomly sampled around the cities in Anhui Provinceof in 2019. Heavy metal element arsenic （As）， lead （Pb）， cadmium （Cd）， chromium （Cr）， mercury （Hg） contents were detected. Health risk was calculated combining the exposure levels of heavy metals and the Chinese residents’ food consumption survey data.Results The detection rates of heavy metals in chicken， egg， liver and gizzard samples were different， and the qualified rate was 100%. The contents of the same heavy metal （except Pb） in chicken， egg， chicken gizzard and chicken liver were significantly different （P<0.05）， and the contents of different heavy metal were significantly different （χ²=17.13， P<0.05）. The content of heavy metals in viscera was higher than that in chicken and eggs， and Cr content was the highest， followed by Pb. The exposure of heavy metals in chicken， eggs and chicken offal in Anhui province was far lower than the health guidance value.Conclusion The accumulation capacity of heavy metals in chicken， eggs and chicken viscera in Anhui Province is different， and heavy metals are more easily accumulated in viscera. The content of heavy metals in chicken， eggs and viscera in Anhui Province is low， the dietary exposure of the population is low， and the risk to human health is relatively small.

Abstract:Objective To provide data for prevention and control of foodborne diseases caused by Vibrio parahaemolyticus from salmon， the serotype， virulence gene and drug resistance of Vibrio parahaemolyticus from salmon in Guangzhou in 2019 were studied.Methods The isolation， quantification and serotype of Vibrio parahaemolyticus in 90 salmon samples were detected based on GB 4789.7—2013. Identification and drug resistance were carried out by automatic microbial identification system， and the virulence genes were detected by PCR amplification.Results Vibrio parahaemolyticus was detected in 16 samples of 90 salmons （17.78%）. The contamination level of positive samples ranged from 3.6 to 93 MPN/g， of which the highest detection rate was found in wholesale market （27.50%）. Seventy two strains which were isolated from positive MPN counting tubes were serotyped into 11 groups by serum agglutination test， the total typing-rate was 80.56%. The isolates were concentrated on serum group O11， O9 and O6 serotypes， accounting for 51.39%. Seventy two isolates carried tlh gene， while tdh and trh gene were not detected. The antibiotic sensitivity analysis revealed that all of the isolates were sensitive to 5 types and 18 kinds of antibiotics such as carbapenems， monobactams， aminoglycosides， quinolones and nitrofurans， 97.22% of the isolates were resistant to ampicillin. A few isolates were resistant to piperacillin （1.39%） and co-trimoxazole （5.56%）， 6.94% of the isolates were resistant to 2 antibiotics， and none of the isolates showed multi-drug resistance.Conclusion The salmons from Guangzhou market were highly contaminated by Vibrio parahaemolyticus， and the serotypes of isolates were diverse. The isolates were nonpathogenic， and they were drug resistance to some extent， which indicated potential risks to human health.

Abstract:Objective To investigate the contamination status， virulence gene distribution， biofilm formation ability and molecular typing characteristics of Staphylococcus aureus （S.aureus） in some commercial cold dishes.Methods Two hundred cold dishes sold in restaurants， supermarkets and street vendor stalls were sampled， and Staphylococcus aureus（S.aureus） were separated. Congo red plate method and crystal violet staining method were used to detect the biofilmforming ability of the isolates. Virulence genes and biofilm genes were detected by PCR， as well as agr typing and multil-ocus sequence typing （MLST）.Results Twenty four strains of S.aureus were isolated， and the detection rate was 10.50%（21/200）； the detection rate of cold dishes was 13.73%（14/102）， and the detection rate of stewed meat product was 7.14%（7/98）； the highest detection rate of seA in the traditional enterotoxin gene was 50.00%（12/24）， and the lowest of seE was 16.67%（4/24）. Poisoning shock syndrome toxin-1 （TSST-1） and leukotoxin （PVL） were 4.17%（1/24） and 25.00%（6/24）， respectively. The detection rate of hemolysin gene was relatively high， and only etd was detected in the dermatoxin gene. The positive rate was 62.5%（15/24） in Congo red plate test and 100% in crystal violet staining； the biofilm genes were mainly cna and clfB， and bap was not detected；the molecular typing of the strains was mainly agr Ⅰ and ST188.Conclusion The S.aureus contamination exsits in some cold dishes sold in Ya’an city. The strains carried multiple virulence genes， had strong film-forming ability and had potential food safety risks.

Abstract:Objective To evaluate the food hygiene status and risk of disease， the microbial contamination of ready-to-eat food in market was investigated， and the biological characteristics of foodborne Salmonella strains was analyzed.Methods The ready-to-eat food sold in 5 large markets with concentrated consumer population were randomly selected for food microbiological detection according to national food safety standards， and Salmonella serotypes， antibiotic resistance and PFGE molecular typing were analyzed.Results The detection rate of coliform bacteria in 131 ready-to-eat foods was 62.59% （82/131）. Salmonella， Bacillus cereus， Staphylococcus aureus and other pathogenic microorganisms were detected， and a variety of Salmonella serotypes were detected. The PFGE pattern was scattered， and the strains showed multiple drug resistance.Conclusion The hygienic status of ready-to-eat food was generally poor. Salmonella was detected in raw meat， which was easy to cause foodborne diseases by cross contamination in ready-to-eat food. Management of ready-to-eat food and raw meat products should be strengthened.

Abstract:Objective To provide a scientific basis for regulatory authorities to develop management measures， sulfur dioxide residues and risk in typical foods in Hubei province market was studied.Methods A total of 1 867 samples of 10 typical foods were collected from supermarkets and farmers’ markets in 15 cities （states） in Hubei province， including day lily （dried）， bamboo shoots （dried）， Yuba （dried）， tremella （dried）， enoki mushroom （fresh）， mushroom （fresh）， pumpkin seeds， konjac powder， pueraria powder and wine. Sulfur dioxide residues were detected according to GB/T 5009.34-2003. The point assessment method was used to calculate the residents’ intake of sulfur dioxide and the exposure risk.Results The total over-limit ratio of 10 types of food was 20.03%（374/1 867）， and the descending order was tremella （dried） ［36.93%（106/287）］， day lily （dried） ［35.10%（106/302）］， Yuba （dried） ［28.31%（77/272）］， pueraria powder ［17.65%（15/85）］， konjac powder ［13.64%（6/44）］， pumpkin seeds ［13.28%（34/256）］， bamboo shoots （dried） ［10.81%（24/222）］， mushroom （fresh） ［3.17%（4/126）］， wine ［1.92%（1/52）］ and enoki mushroom （fresh） ［0.45%（1/221）］. The mean value of sulfur dioxide residues in 10 types of food ranged from 0.02 to 1.18 g/kg. The average daily dietary intake of sulfur dioxide of residents in Hubei province ranged from 0.28 to 0.59 mg/kg?BW?d， and the daily intake （97.5 th percentile， P97.5） of people with high food consumption was 1.81~3.78 mg/kg?BW?d， which exceeded the ADI （0~0.7 mg/kg?BW?d）.Conclusion Sulfur dioxide residues in day lily （dried）， tremella （dried） and Yuba （dried） were more serious in Hubei province. The average daily intake of sulfur dioxide of residents was acceptable， but the high food consumption of population hasd a high health risk.

Abstract:Objective By revealing the predictors of consumers’ willingness of food safety governance， this study could provide theoretical model for subsequent researchers and practical evidence for stimulating public participation in social co-governance of food safety in China.Methods From the perspective of planned behavior theory， this study investigated the relationship between subjective norms， behavioral attitudes， risk perception， victimization experience and consumers’ willingness of food safety governance through 300 random samples nationwide.Results The results showed that subjective norms significantly positively affect consumers’ behavior and attitude towards food safety， and then enhanced their risk perception ability and willingness of food safety governance， and the chain mediation model was established successfully. In the total effect of “behavior attitude → food safety governance willingness”， “subjective norm → food safety governance willingness” and “subjective norm → risk perception”， the indirect effect accounted for 17.5%， 20.0% and 36.7%， respectively. The food victimization experience of consumers had a significant positive moderation effect on the direct path of “risk perception → food safety governance willingness” and two indirect mediation effect paths.Conclusion The research aims to scientifically guide the public to actively participate in food safety governance， break the dilemma of food safety risk governance of the single stakeholder， and provide practical theoretical model reference and practical guidance for the realization of social co-governance in food safety in China.

Abstract:To summarize thepractice and experience of targeted food hygiene security measures in a major field activity of the army in order to provide references for diverse tasks. Considering the characteristics of heavy activity， field operations and the influence of COVID-19， a series of support measures related to food hygiene surveillance were strengthened. The first measure was review of recipes， health management and training of employees， procurement and storage of raw materials， warehouse management， processing and manufacturing management， disinfection of tableware， as well as food sample retention. Secondly， the control points that probably cause spread of COVID-19 in the phase of food service industry were analyzed， then relevant supervision and guidance were carried out from the aspects of employees and diners， foods of cold chain logistics， environment and emergency response plan. Finally， in order to assure the safety of food processing and crowd-gathered diet in the field， the following measures were guided to adopted including selecting the site of cooking and dining properly， cleaning the environment， making dishes using pure water and semi-manufactured foodstuff， keeping food sanitation in the course of transport and dinning， as well as supervising the robot machines for cooking automatically. The main experiences were listed as follows： promoting food safety awareness of the principal and the employees of the canteen， enhancing legal enforcement capacity and technical capacity of health supervisors， focusing on new risks related to food safety as well as reinforcing the management of health supervisors and employees in the field.

Abstract:Since the implementation of the “Administrative Measures for the Registration of Food for Special Medical Purposes” on July 1， 2016， the registration management system for food for special medical purposes （FSMP） has been gradually established and improved. The implementation of the system has played an important role in ensuring the safety， nutritional adequacy， clinical effect for special medical purposes of product， regulating the development of the industry， and consolidating the foundation of market supervision. Under the background of “Implementing the Healthy China Strategy”， in order to meet the nutritional needs of special populations， it is necessary to further improve the registration management system on FSMP through various measures， continue to ensure the quality and safety of FSMP， improve the efficiency of registration management， improve the availability of the product， and continue to normalize the development of the industry.

Abstract:A milk and egg cake， which had a short shelf life and were sold on the spot， was found unqulified during a municipal food safety supervision and sampling inspection. The bakery raised objection because the labortory report date was behind the expiration date of the product. It required a double check， while according to the relevent regulations， the reserved sample had also expried. This review put forward solutions on how to improve the legal regulations for food safety supervision and sampling， strengthen the risk control of inspection and testing institutions and effectively fulfill the responsibility of the enterprise.

Abstract:Objective Vitamin D₂ mushroom powder has been listed as a new edible raw material in relevant regulations of EU， USA， Australia and New Zealand following the existing regulatory standards. There is no regulation or standard in China and CAC or other countries and international organizations about the approvement of the use of this raw material. The production technology and product characteristics of vitamin D₂ mushroom powder， relevant laws， regulations and standards at home and abroad are discussed and analyzed. As an emerging food ingredient， the food trade and food safety regulatory authorities should pay attention to the development of vitamin D₂ mushroom powder. It may refer to the relevant regulations and standards of relevant countries and international organizations when implementing product development， food safety regulation and formulating consumer guidance.

Abstract:Objective To provide reference basis for the prevention， control and disposal of similar events in the future， the suspected food and pathogenic factors of a foodborne disease outbreak involving several kindergartens were investigated and traced.Methods Pathogen was detected in 32 samples collected from three kindergartens by rapid detection techniques （real time fluorescence PCR and mass spectrometry） combined with traditional identification methods， such as isolation and culture， enzyme linked immunosorbent assay （ELISA）. Descriptive epidemiological investigation method and pulsed field gel electrophoresis （PFGE） were performed to analyze the molecular traceability of pathogenic factors.Results There were 568 children in the three kindergartens， and 62 （10.92%） cases were found. The clinical manifestations were vomiting， diarrhea and so on. Staphylococcus aureus was detected in 10 biological samples and 2 preserved shredded pork floss cakes distributed by the same catering company. The plate counts of S. aureus in this two cakes were 2.0×10⁷ CFU/g and 1.4×10⁷ CFU/g， respectively. Staphylococcus enterotoxin gene type A （sea） and enterotoxin type A （SEA） were detected simultaneously from 11 isolates of S. aureus strains in patients and suspicious food. PFGE fingerprint showed the same type， suggesting the case and food isolates were the same exposure source.Conclusion The outbreak in three kindergartens was caused by the shredded pork floss cake contaminated with Staphylococcus enterotoxin， which distributed by the same catering company. The supervision of school food materials should be further strengthened.

Abstract:Objective The spatial autocorrelation analysis of toadstool poisoning in Jiangxi Province from 2016 to 2020 was carried out to explore the spatial distribution characteristics of the disease.Methods The surveillance data of toadstool poisoning in Jiangxi Province from 2016 to 2020 were collected and analyzed descriptively. ArcGIS 10.2 software was used to make vector maps of Jiangxi Province， geoda 1.12 software was used to merge case data with geographic attribute data and performed global spatial autocorrelation analysis and local spatial autocorrelation analysis.Results A total of 938 cases of toadstool poisoning were reported in Jiangxi Province， with an average annual incidence rate of 0.402 2/100 000. The difference was statistically significant in the global autocorrelation analysis from 2016 to 2020. It showed spatial clustering （Moran’s I=0.107 0， P=0.032<0.05）. Local spatial autocorrelation analysis results showed that Poyang county， Xiajiang county and Yugan county were high-high areas. De’an county， Jing’an county， Shangli county and Longnan city were low-low areas； Xinjian districts， Zhangshu City， Pengze County and Hukou County were low-high areas. Nankang district and Donghu district were high-low areas.Conclusion The number of toadstool poisoning cases in Jiangxi Province from 2016 to 2020 showed that the overall number of cases was spatially clustered. Some areas were key areas. Relevant departments should strengthen targeted prevention and control measures， and accurate science popularization and education was recommended.

Abstract:Objective To provide reference for preventing and controlling the family foodborne disease， the epidemiological characteristics of family foodborne disease outbreaks in Jiangxi Province was analyzed.Methods The descriptive analysis was conducted on the data of family foodborne disease outbreaks in Jiangxi Province reported through Foodborne Disease Outbreak Reporting System from 2012 to 2020.Results From 2012 to 2020， a total of 715 families， 2 608 illnesses and 35 deaths from foodborne disease outbreaks were reported in Jiangxi Province. The case fatality rate was 1.3% （35/2 608）. The number of family foodborne disease outbreaks was on the rise within the 9 years， and most of the incidents occurred during May to October. From the analysis of pathogenic factors and causative food， wild mushroom caused the most incidents， cases and deaths， accounting for 45.0% （322/715）， 39.5% （1 029/2 608） and 94.2% （33/35） of the total respectively， followed by microorganism pathogenic factor. From the analysis of areas distribution， the most incidents occurred in rural families， the incidents， cases and deaths accounted for 73.1% （527/715）， 75.4% （1 966/2 608） and 100.0% （35/35）， respectively.Conclusion In the high incidence season of foodborne diseases in Jiangxi Province， the publicity of the risk of eating wild mushroom and the knowledge of microbial foodborne diseases should be targeted at rural families to reduce the incidence of family foodborne disease and death.

Abstract:Objective To provide data basis of foodborne disease control， the pathogen of foodborne diseases in Chongqing， dietary history and the source of food were analyzed.Methods The information of foodborne disease cases in 27 sentinel hospitals in Chongqing from 2019 to 2020 were collected. Stool specimen or swab from foodborne disease cases was collected to detect Salmonella， Vibrio parahaemolyticus， diarrheagenic Escherichia coli， Shigella and Norovirus.Results Four thousand two hundred and ninety four diarrhea cases were collected. The positive rate of pathogens was 12.09% （519/4 294）， including 5.33% of Norovirus， 4.66% of Salmonella， 1.96% of diarrheogenic Escherichia coli， 0.12% of Shigella and 0.02% of Vibrio parahaemolyticus. The pathogen detection rates were higher in the second （18.50%） and third （13.00%） quarter than others and obviously peaked in summer and autumn. The highest pathogen detection rate was 19.19% （71/370） in 0-1 years old group. 4 289 of 4 294 cases provided suspicious diets information， among which were mainly meat and meat products 19.26% （846/4 289）， grain and grain products 17.65% （757/4 289）， 58.27% （2 502/4 289） of the foods were homemade， 30.64% （1 314/4 289） were from catering service industry， 55.42% （2 377/4 289） of the food came from family， restaurants accounted for 12.17% （522/4 289） and retail stores accounted for 10.91% （468/4 289）.Conclusion Norovirus and Salmonella were the main pathogens of foodborne illness cases in Chongqing， and the suspicious food was mainly homemade from family sources. It is suggested to strengthen food safety supervision in summer and autumn with high incidence of foodborne diseases， focus on 0-1-year-old infants， and carry out family food hygiene and safety knowledge education. To provide technical support for effective prevention and control， the active monitoring of foodborne diseases should be strenghened.

Abstract:Objective To investigate the reason of Bongkrekic acid food poisoning outbreak， and prevent similar incidents from happening again.Methods Pathogenic factors were determined by rapid detection. Suspicious meal and food were inferred according to the incubation period of pathogenic factors. Poisoning meal and food were determined by combining survey results from epidemiological investigation， food hygienic investigation， environmental hygienic investigation， sampling and detection.Results Epidemiological investigation showed that there was a correlation between food and the morbidity. The incubation period and clinical manifestations of patient were in accordance with the characteristics of Bongkrekic acid food poisoning. Bongkrekic acid was detected in the food sample and patient blood.Conclusion The poisoned meal was the dinner on July 19， 2020， and the poisoned food was stir-fried rice noodles. The main cause of this was the violation of the food safety operation by food factory operator and employees during production and transportation， which caused bacterial proliferation and produced toxin in contaminated rice noodles.

Abstract:Objective To investigate two food poisoning incidents in Quzhou City， determine the causes of the incidents， and provide basis and suggestions for the prevention and control of similar poisoning incidents.Methods Epidemiological investigation was carried out on two food poisoning incidents in Quzhou City in 2020 and 2021， and the causes of the incidents was determined by comprehensive analysis of food exposure history， clinical symptoms and characteristics， laboratory test results， etc.Results A total of 14 cases were diagnosed in these two food poisoning incidents， and the incubation period was 20 min to 4 h. The main clinical symptoms of 14 cases were similar， including diarrhea， abdominal pain， nausea， vomiting and dizziness. All cases had a history of eating bitter gourd. In these two food poisoning incidents， cucurbitacin B were detected by ultra performance liquid chromatography-triple quadrupole mass spectrometry using atmospheric pressure chemical ionization. The content of cucurbitacin B in bitter gourd sample was 150 mg/kg， the content of cucurbitacin B in leftover sample containing bitter gourd was 69.9 mg/kg. The content of cucurbitacin B in blood sample of one case was 2.7 μg/L， and the content of cucurbitacin B in 5 urine samples was 0.14-0.59 μg/L.Conclusion These two food poisoning incidents were caused by bitter lagenaria siceria. It is suggested that the food regulatory authority and the health department should strengthen health education among caterting service personnel and the public to prevent the poisoning incidents.

Abstract:Objective To explore the relationship between eating out and diarrhea in Chinese residents.Methods Based on the data of Epidemiological factors of key disease in 8 cities of China from the National Health and Family Planning Dynamic Monitoring project in 2017， the relationship between eating out and diarrhea was analyzed by SPSS.Results A total of 14 000 subjects were included in the analysis， including 7 172 （51.2%） males， with an average age of （34.6±10.1） years old. 2 419 patients had diarrhea with an incidence of 17.5%. The results of univariate analysis showed that gender， age， ethnicity， educational background， type of drinking water， whether they often ate cold dishes， whether they separated raw and cooked kitchen knives and chopping boards， and the type of meals at different times were statistically correlated with diarrhea， and P value were all lower than 0.05. After adjusting for 9 confounders， such as gender， age， ethnicity， education level and marital status， Logistic regression analysis showed that the OR （95%CI） of those who ate in the canteen was 1.45 （1.19~1.77） compared with those who ate at home. The adjusted OR （95%CI） of eating out for one meal， two meals and three meals were 1.28 （1.14~1.44）， 1.58 （1.25~1.94） and 2.28 （1.58-3.29）， respectively.Conclusion Eating out， especially take-out/street stalls/fast food restaurants， increased the risk of diarrhea. Residents should be encouraged to reduce eating out.

Abstract:Objective To analyze the epidemiological characteristics and regularity of Burkholderia gladioli poisoning in China from 2005 to 2020， and provide scientific basis for prevention of fermented rice noodle poisoning.Methods Poisoning incidents of Burkholderia gladioli in China from 2005 to 2020 were collected， retrospective descriptive analysis was performed on the data related to the event， and statistical analysis was performed by Excel 2013 and SPSS 26.0 software.Results From 2005 to 2020， a total of 30 incidents of Burkholderia gladioli poisoning were reported in China with 188 cases and 85 deaths， and the fatality rate was 45.21%， major indidents accounted for 93.33% （28/30） of the total number of incidents， and the fatality rate was 53.13%. The main clinical manifestations were vomiting， abdominal pain， dizziness and diarrhea. It mainly occurred from May to September. Poisoning cases of Burkholderia gladioli were reported from 22 counties in seven provinces， mainly in the south， southwest and northeast of China. The incidences occurred in all age groups， and the fatality rate increased with age. The main poisoning foods were cereals and agaric. In cereal food， home-made fermented cereal products account for 80.0%. In south and southwest China， corn wrappers， glutinous corn dumplings and rice noodles were the main food， while in north China， sour corn noodle was the main food.Conclusion Burkholderia gladioli poisoning often draws the attention of the society because of its high fatality rate. Between 2005 and 2020， poisoning incidents caused by Burkholderia gladioli were reported in all years except the year of 2013， 2017 and 2019. The incident occurred mainly in rural areas， mainly in home-made fermented cereal food. In recent years， poisoning incidents caused by commercially available rice noodle occurred in urban areas， which should be paid attention seriously. Prevention of Burkholderia gladioli poisoning should mainly focus on food processing and food hygiene management， promoting scientific diet， and improving food safety awareness.

Abstract:Objective To provide the scientific basis for nutrition and health policy， the egg consumption among adult residents of large cities in China from 2017 to 2018 was analyzed.Methods Samples were chosen from China Food Consumption Survey （2017—2018）. 12，173 participants aged 18 years old and above were included in the final analysis. Three non-consecutive 24 h within 3 d recalls were used to collect dietary consumption data. The rate of egg consumption and total egg consumption were calculated. Chi-square test and non-parametric test were used to compare the differences of the consumption rate and consumption， respectively.Results The overall consumption rate of egg among adult residents of large cities in China from 2017 to 2018 was 72.9% （8 875/12 173）. The average consumptions of egg among urban adults in 18 provinces of China from 2017 to 2018 were 28.1 g/d （P25： 0， P50： 20.5 g/d， P75： 43.9 g/d， P95： 78.3 g/d）， and 38.6 g/d （P25： 17.6 g/d， P50： 33.3 g/d， P75： 51.3 g/d， P95： 86.9 g/d） in the consumers. Highly educated and high income adults and adults in the eastern region were more likely to consume egg and had higher intake of egg. 9.9% （1 201/12 173） of the adults consumed more eggs than the Chinese dietary reference intake （40 g/d）， while the consumption of 71.5% （8 705/12 173） of the adults were lower than the reference.Conclusion Egg is common among the diet of Chinese urban adults， while the consumption is insufficient. Actions should be taken to promote the intake of egg in China.

Abstract:Objective To investigate the current intake and nutrition knowledge of milk and dairy product in high school students in Ya’an， and to provide a basis for nutrition promotion policies in economically underdeveloped areas in China.Methods From August to October in 2020， 3 288 high school students from Ya’an were selected as survey subjects， and completed paper questionnaires under the guidance of investigators.Results The passing rate of high school students’ awareness of milk nutrition knowledge was 21.64%. The milk intake rate of all students in the school was 77.96%， and the insufficient milk intake rate was 88.12%； and the median intake of milk and dairy products was 117.14 g/d. Compared with students’ milk nutrition knowledge level and milk intake under different characteristics， it showed that urban students were higher than rural students， and girls were higher than boys. Moreover， the cognitive level of milk nutrition in grade three was higher than that in other grades， and the high-income families had higher cognitive level than those in low-income families with statistical significance （P<0.05）.The multivariate logistic regression analysis showed that the age of students， resident student， mother’s education， nutrition knowledge of milk and families income were independent risk factors for consumption of milk and dairy product［odds ratio（OR）=0.894，95% confidence interval（CI）：0.810~0.987）， OR=0.553， 95%CI∶0.434~0.706，OR=1.289， 95%CI∶1.047~1.587，OR=1.167， 95%CI∶1.112~1.225， OR=1.123， 95%CI∶1.006~1.253］.Conclusion The county’s senior high school students had a low level of knowledge about milk nutrition. Although the milk intake rate was high， the daily intake was obviously insufficient. Elder age， resident students， low level of milk nutrition knowledge， low education level of their mothers and low family’s per capita monthly income was more likely to have insufficient milk intake. The education of milk nutrition and health knowledge should be strengthened for such students to promote milk intake .

Abstract:The induction of food allergy can be roughly divided into three stages： the sensitization， elicitation and effect stage. In the sensitization stage， the allergens in food pass through the intestinal mucosal immune barrier， undergo antigen-presenting cell processing， T cell activation and other steps， and then induce the IgE production and binding on the surface of mast cells and basophils. In the elicitation and effect stage， food allergens react with the bond IgE on mast cells and basophils， causing them to release the immune mediators such as amines and leukotrienes. The mediators bind with corresponding receptors on the effector organs and trigger allergic reactions in the body. The basic cause of food allergy is the destruction of oral immune tolerance to specific allergens in some individuals. Inducing the establishment and rebuilding of oral immune tolerance is a promising way to deal with food allergy. Or it can break through the bottleneck that there is currently no effective cure for this disease. To provide help for the prevention and treatment of food allergy， the regulatory T cells that play a central role in the establishment and rebuilding of oral immune tolerance， and their closely related factors such as dendritic cells， regulatory B cells， intestinal flora and its metabolites， are reviewed.

Abstract:Ursolic acid is a naturally occurring triterpenoid compound with a wide range of biological activities， such as blood lipids regulation， anti-inflammatory， anti-cancer， anti-oxidation， heart and liver protection， anti-skeletal muscle atrophy， anti-virus， etc. Due to its numerous biological functions， it has become a promising candidate for the prevention and treatment of various diseases. In addition， China has abundant plant resources of traditional Chinese medicine. Ursolic acid can be obtained from many common plants， such as sea buckthorn， lavender and apple peel. Ursolic acid and its synthetic derivatives are also involved in a series of fields related to disease prevention. Therefore， it is very important to explore the functional role of ursolic acid for clinical use. This article summarizes the functional effects of ursolic acid and related mechanisms to provide new ideas for the treatment and prevention of other diseases.

Abstract:Bacillus cereus（B.cereus） is a common foodborne opportunistic pathogen， which causes foodborne diseases to seriously affect consumers’ health and social economy. This paper reviews the research progress on prediction models and its application in risk assessment of B.cereus contamination in food at home and abroad， and summarizes the factors， food categories， production chain， primary and secondary model fitting methods. It is found that the temperature， food ingredients， water activity， pH and so on affect the proliferation of B.cereus， and temperature is the main factor. Animal food and rice and its products were the main food categories. Gompertz model， Logistic model， Baranyi model， Weibull models etc are often used to fit growth or inactivation curves to establish primary models. Quadratic polynomial model and square root model are commonly used to fit the change of growth rate or lag time to establish the secondary model. On this basis， a three-stage model is established by software system. The current risk assessment studies only involve the production or from sales to consumption， and there is no report on the B.cereus prediction model of certain food from raw materialto consumption. The prospect of quantitative risk assessment modeling of B.cereus contamination in food is put forward to provide reference for future research.

Abstract:Because of an increasing demand on food quality and safety from consumers， active food contact materials that can improve food freshness and extend shelf life are emerging. This paper summarizes and analyzes the types， functions， mechanism and application methods of active substances commonly used in active food contact materials at present. The regulations and standards of active food contact materials at home and abroad are discussed. The existing problems and development directions are summarized to provide scientific basis for promoting safely use， commercial produce and regulation formulation.