Abstract:With the continuous rise of China's economic level, people's demand for dietary structure and nutritional level has gradually increased. Improving nutritional health level has become an important part of realizing common prosperity and building healthy China. At present, China has carried out multi-sectoral linkage nutrition and health work system, and pushed out of many politics and measures that achieved very great development. But the construction of China's nutrition and health work system is still in the exploratory stage, and the current situation of national nutrition is still severe due to unreasonable dietary structure, unbalanced regional development, imperfect regulatory standards, unsystematic personnel training and other factors. It is suggested that through policy guidance, should further change the concept of nutrition, promote regional efforts, improve laws and regulations and improve the talent system, in order to improve the level of national nutrition and health.

Abstract:Objective To study the molecular characteristics and antibiotic resistance of Bacillus cereus(B.cereus ) from foods in Shanghai. Methods The B.cereus isolates were characterized using antibiotic susceptibility tests and whole genome sequencing (WGS). BioNumerics software was used to analyze and assemble WGS data. Then, multilocus sequence typing (MLST), virulence genes profiles and antibiotic resistant genes were analyzed using assembled genome sequences. The antimicrobial susceptibility was investigated. Furthermore, STs of B.cereus in this study were compared with those from PubMLST database. Results In this study, all 37 isolates were confirmed as B.cereus isolates. The 37 B.cereus were typed into 34 STs with 7 new STs. The result of STs showed high diversity. All 37 B.cereus isolates had nheA, nheB and nheC genes. The positive rate of hblACD genes was 37.8%. However, only 16.2% of B.cereus had ces genes. Furthermore, two ST26 B.cereus isolates with ces genes from ready-to-eat food were identified. The antibiotic resistance rate to Ampicillin, Penicillin and Oxacillin was high, which was not consistent with antibiotic resistant genes. Conclusion The STs of 37 B.cereus from food in Shanghai showed high genetic diversity, which suggested the molecular surveillance should be enhanced. Fundamental data can be obtained using whole genome sequencing for tracing B.cereus isolates and analyzing pathogenicity.

Abstract:Objective The present study was undertaken to identify the serotypes and drug resistance profiles of Salmonella recovered from diarrheal patients in Anhui Province, and provide evidence for the diagnosis and treatment of foodborne diseases caused by Salmonella. Methods From 2015 to 2020,980 Salmonella were collected from 16 Centers for Disease Control and Prevention in Anhui Province. The strains were serotyped, and the drug susceptibility profile was studied by micro-broth dilution method. Results Nine hundred and eighty Salmonella included 82 serotypes with a predominance of Salmonella enteritidis 31.43% (308/980), Salmonella typhimurium 26.22% (257/980), Salmonella agona 7.35% (72/980), Salmonella thompson 6.63% (65/980) and Salmonella london 3.37% (33/980). The highest resistance were ampicillin (AMP), nalidixin (NAL), tetracycline (TET) and ampicillin/sulbactam (AMS), which were 62.35%, 47.96%, 47.86%, 43.16%, respectively. The resistance rates to AMP, AMS, NAL, cefoxitin (CFX), and azithromycin (AZM) showed a significant upward trend (P<0.05). The drug resistance of Salmonella showed different features in different regions. It was worse in the north than the south and central Anhui Province. The multi-drug resistance rate reached 40.41%, and Salmonella typhimurium and Salmonella london were highly resistant to multiple drugs. Conclusion From 2015 to 2020, the predominant Salmonella serotypes of diarrheal patients in Anhui Province were Salmonella enteritidis, Salmonella typhimurium, Salmonella agona, Salmonella thompson and Salmonella london. Drug resistance was serious, and most resistance rate showed an increasing trend from 2015 to 2020. The multiple drug resistance was a serious problem. It is necessary to pay close attention to monitor the resistance of Salmonella in Anhui Province.

Abstract:Objective To understand the molecular epidemiology and antimicrobial resistance pattern of clinically isolated Salmonella in Shaoxing city from 2017 to 2019. Methods The 245 Salmonella strains that were isolated from foodborne disease and diarrhea cases in Shaoxing were collected and serotyped. Broth microdilution method was performed to carry out drug resistance testing. Pulsed field gel electrophoresis (PFGE) and BioNumerics V7.1 software were applied to clustering analysis. Results The 245 isolates of Salmonella were composed of sixty serotypes. The predominant serovars were Salmonella typhimurium (32.24%), Salmonella enteritidis (10.20%) and Salmonella london (6.94%). The 225 strains were resistant to 25 antibiotics at different degrees. Among these isolates, higher rates of resistance to ampicillin (77.14%), tetracycline (73.88%) and streptomycin (66.53%) were found and the multiple drug resistance rate reached 76.33%. On the other hand, the predominant serovars were digested with Xba Ⅰ, which contained 48,11 and 12 different PFGE fingerprints, respectively. Conclusion Salmonella serotypes and PFGE fingerprints were highly diverse. Antibiotic resistance was concentrated in AMP-TET-STR.

Abstract:Objective To investigate the epidemiological characteristics and drug resistance of foodborne diseases in Jinnan District by monitoring and drug resistance analysis of foodborne diseases from 2018 to 2020, so as to provide basis for prevention and control of foodborne diseases. Methods The stool samples of 607 cases of foodborne diseases in sentinel hospitals of Jinnan District from 2018 to 2020 were detected for Salmonella, diarrheogenic Escherichia coli, Vibrio parahaemolyticus and Shigella, and the drug sensitivity of positive strains was analyzed. Results A total of 124 positive strains were detected in 607 stool samples, with a positive detection rate of 20.43% (124/607). There were 74 strains of Salmonella, 31 strains of Vibrio parahaemolyticus, 19 strains of diarrheogenic Escherichia coli, and no Shigella was detected. The ratio of male to female was 4∶3 (347/260). The highest detection rate in Salmonella was Salmonella enteritidis(62.16%, 46/74), and the highest detection rate in diarrheogenic Escherichia coli was enteropathogenic Escherichia coli (EPEC). In drug sensitivity test, Salmonella and diarrheogenic Escherichia coli were significantly resistant to ampicillin (AMP), up to 72.04% (67/93), and multiple drug resistance was common. Vibrio parahaemolyticus was most resistant to cefazolin (CFZ) (77.42%, 24/31). Conclusion Salmonella enteritidis and EPEC are the main pathogens of foodborne diseases in Jinnan District of Tianjin from 2018 to 2020. Strains are resistant to AMP with multi-drug resistance. It suggested that the relevant departments should strengthen the supervision of food processing industry, and strengthen the monitoring of drug resistance of pathogenic bacteria, so as to provide the basis for food safety and clinical treatment in Jinnan District.

Abstract:Objective In order to discover the pulsed field gel electrophoresis (PFGE) serotypes and drug resistance of Salmonella agona (S. agona) in Sichuan Province during 2008 to 2018, so as to understand the contamination status of S. agona and provide reference data for outbreak warning, traceability investigation and antibiotic use strategy. Methods A total of 61 S. agona strains after the serological and biochemical identification were analyzed by PFGE and tested for minimal inhibitory concentration of 14 antibiotics. Results The isolates of S. agona were divided into 41 PFGE types, some strains isolated from clinical cases in different years and regions had the same PFGE type, one pork isolate had the same PFGE type as some clinical isolates. The antibiotic resistance test indicated 28 of the isolates were sensitive to 14 kinds of antibiotics, the other 33 strains showed different degrees of drug resistance, nearly half of the strains were insensitive to tetracycline; and there were 16 multidrug-resistant strains. All of the isolates were sensitive to imipenem. Conclusion The PFGE types of S. agona isolated in Sichuan from 2008 to 2018 showed diversity, and they were sporadic prevalent in Sichuan Province. The drug resistance was serious with an increasing trend.

Abstract:Objective Establishing the database of food-borne Salmonella typhimurium 1,4,[5],12∶i∶- and monophasic variant in Guangxi Zhuang Autonomous Region by investigating the drug resistance and molecular typing characteristics of the isolates in 2018. Methods 124 strains of S.1,4,[5],12∶i∶- from clinic samples and food samples were tested for drug sensitivity by minimum inhibitory concentration (MIC), and molecular typing by pulsed field gel electrophoresis (PFGE). Results One hundred and twenty four strains of S.1,4,[5],12∶i∶- were all sensitive to imipenem, but resistant to the other 13 antibiotics at different levels. The resistance rate to tetracycline was the highest (96.8%, 120/124), followed by ampicillin (95.2%, 118/124). Multidrug resistant (MDR) rate was 26.6% (33/124), and 47.1% S.1,4,[5],12∶i∶- isolates were multi-resistant to ACSuT. The S.1,4,[5],12∶i∶- strains were differentiated into 104 Xba I PFGE patterns with similarity of 72.9%-100%, and the dominant patterns were JPXX01.GX0114 (5 isolates) and JPXX01.GX0294 (4 isolates), all of which came from foodborne disease surveillance. Conclusion The result indicated that the S.1,4,[5],12∶i∶- isolates in Guangxi were highly resistant to penicillins and tetracyclines and drug resistance situation was not optimistic, S.1,4,[5],12∶i∶- PFGE pattern were highly sporadic. It is necessary to trace the molecular origin of the isolated strains on time, which can improve ability to identify potential food-borne S.1,4,[5],12∶i∶- outbreak events in sporadic cases.

Abstract:Objective To study the epidemiological characteristics and drug sensitivity of Salmonella in Huadu District of Guangzhou from January 2016 to December 2020, so as to provide scientific basis for prevention, control, diagnosis and treatment of diseases caused by this kind of pathogens. Methods Six thousand six hundred and sixty-five fecal samples of diarrhea patients in Huadu District of Guangzhou city from 2016 to 2020 were collected for isolation, identification, serotyping and drug sensitivity test. Results A total of 435 Salmonella strains were detected, with a total detection rate of 6.53%. The infection population was mainly infants (0-3 years old), and the sex ratio was male∶female=1.18∶1, which was not statistically significant. The epidemic peak was from May to November. General pediatrics, emergency medicine and gastroenterology were the three clinical departments with the highest positive detection rate. Salmonella typhimurium and Salmonella dublin were the dominant strains in the epidemic. Drug sensitivity test showed that the resistance rates of Salmonella to ampicillin, tetracycline, piperacillin and ampicillin/sulbactam were very high. The drug resistance rate of cephalosporins ranged from 17.01% to 22.63%. The resistance rate of quinolones (levofloxacin and ciprofloxacin) increased slightly. The result showed that the dominant strain of Salmonella in this area, Salmonella typhimurium, was less sensitive to β-lactam antibiotics in this study. Conclusion In the recent 5 years, Salmonella infection in Huadu District of Guangzhou city was on the rise, especially in infants. The drug resistance of Salmonella in this area was relatively strong, especially Salmonella typhimurium. It suggested that the monitoring of the epidemic should be strengthened in this area, and antibiotics be used reasonably in the treatment.

Abstract:Objective A sensitive and rapid method was developed for the determination of 17 β-adrenergic receptor blockers(β-blockers) by ultra performance liquid chromatography tandem mass spectrometry(UPLC-MS). Methods The β-blockers were extracted from porcine sample with acetonitrile, purified by solid phase extraction column Oasis Prime HLB. The analytes were then separated by the Endeavorsil C18 chromarographic column with methanol and 0.1% formic acid as gradient mobile phase. The ion fragment information analytes were obtained using ultra performance liquid chromatography-tandem mass spectrometry under multiple reaction monitoring mode and the isotope internal standards were used to quantify by calibration curves. Results The linear ranges of 17 β-blockers were from 0.2 to 20 μg/kg, with correlation coefficient(R)＞0.999. The limits of detection(LOD) were 0.05-0.07 μg/kg, and the limits of quantification(LOQ) were 0.15-0.2 μg/kg. The average recoveries of β-blockers(added into blank porcine samples at three concentration levels) ranged from 84.97% to 123.40%, and the relative standard deviation (RSD) was 0.41% to 13.94%. Conclusion The method is simple, sensitive, accurate and is suitable for the confirmation and quantification of β-blockers in porcine samples.

Abstract:Objective To establish a method for the determination of selenium species in Se-enriched garlic with high performance liquid chromatography-inductively coupled plasma tandem mass spectrometry (HPLC-ICP-MS/MS). MethodsZORBAX SB-Aq column was used as analytical column; 10 mmol/L citric acid (ammonium citrate), 5 mmol/L sodium hexane sulfonate and 2% methanol were used as mobile phase for gradient elution. Baseline separation of selenate (SeO2-₄), selenite (SeO2-₃), selenocysteine (SeCys2), methylselenocysteine (MeSeCys), selenomethionine (SeMet) and Selenoethionine (SeEt) were completed in 10 min. Constant temperature oscillating assisted enzyme extraction was used to extract selenium species in garlic samples. Results The detection limits for SeO2-₄, SeO2-₃, SeCys2, MeSeCys, SeMet and SeEt were 0.40,0.40,0.44,0.47,0.35 and 0.45 μg/kg, respectively. The linear correlation coefficients (r) were all above 0.999 in the range of 0-100.0 μg/L. Except SeCys2, the recoveries were between 79.0%-104.0% and the relatives standard deviations were within 2.2%-5.0%. Conclusion The result showed that the method had good stability with high sensitivity and accuracy, and was suitable for determination of five selenium species in garlic.

Abstract:Objective To investigate and trace the source of Salmonella enteritidis food poisoning in a welfare institution, so as to provide reference for the study of similar foodborne disease. Methods Epidemiology, food hygiene and pulsed field gel electrophoresis (PFGE) technology were used to investigate and analyze the incident. Results There were 23 confirmed cases of foodborne disease, and the incidence rate was 5.65% (23/407); 15 anal swabs were collected from patients, as well as 3 anal swabs from kitchen staff, 3 preserved dishes, 2 fruits and 1 cold drink. Salmonella enteritidis was detected from 11 anal swabs. PFGE typing result showed that the similarity of 11 strains of Salmonella enteritidis was 96.4%, and cluster analysis showed that they were the same type. It was preliminarily determined that the strain was from the same clone line. Conclusion Based on the analysis of epidemiology, food hygiene and laboratory test result, it was confirmed that the foodborne disease was caused by Salmonella enteritidis. Welfare institutions should strengthen the management of food safety for special groups, and formulate corresponding emergency response plans for food poisoning emergencies to prevent the recurrence of such accidents.

Abstract:Objective To investigate the contamination status, serotyping and antibiotic resistance of Salmonella in raw poultry meat in Fujian Province in 2020. Methods Salmonella was isolated from 178 raw poultry meat samples according to GB 4789.4—2016, serotyping and drug resistance experiments were performed on the isolated Salmonella. Results Forty strains of bacteria were detected, with a detection rate of 22.5% (40/178). By serotyping, Salmonella typhimurium accounted for the highest proportion with a detection rate of 22.5% (9/40), followed by Salmonella kentucky and Salmonella enteritidis with the detection rate of 17.5 (7/40) and 15.0% (6/40), respectively. The results of drug resistance experiments showed that these 40 strains of Salmonella were most resistant to tetracycline with a resistance rate of 77.5% (31/40), followed by nalidixic acid and ampicillin with resistance rates of 62.5% (25/40) and 52.5% (21/40), respectively. The multiple drug resistance rate (MDR) was 52.5% (21/40). Conclusion There was a certain degree of contamination of Salmonella in the raw poultry in Fujian Province in 2020, which was mainly dominated by S. typhimurium. The situation of drug resistance was serious, and there was a high rate of multi drug resistance. Food safety risk monitoring should be enhanced to prevent the outbreaks of foodborne diseases.

Abstract:Objective The study aims to analyze the drug resistance, virulence genes and molecular typing of Vibrio parahaemolyticus (VP) identified in Zaozhuang from 2019 to 2020. Methods The VP strains were isolated and identified, following the Vibrio parahaemolyticus test protocol in the National Food Safety Standard (GB 4789.7—2013). The broth microdilution method was performed to determine the resistance of VP to 12 antibiotics. Their virulence genes (tlh, tdh, trh) were detected by real-time quantitative polymerase chain reaction (PCR). Pulsed field gel electrophoresis (PFGE) was applied for molecular typing, and the strain clustering was analyzed by BN software. The chi-square test was used to analyze the statistical result (α=0.05). Results The detection rate of VP was 4.57% out of 678 patients’ stool samples. Among the 31 identified VP strains, the resistance rate to cefazolin was 58.06%, and the multi-drug resistance rate was 12.90%. The positive rates of virulence genes tlh, tdh, trh were 100%, 96.78%, 3.22% respectively. The 31 VP strains were further divided into 17 band types and 2 band clusters. The dominant band type cluster covered 93.55% of the strains. Conclusion The VP strains in Zaozhuang from 2019 to 2020 were highly resistant to cefazolin. Some strains showed multiple drug resistance. They mainly carry two virulence genes, tdh and tlh. The PFGE bands were well-clustered, suggesting high homology among these VP strains. Epidemiological investigation and tracing of VP strains should be strengthened in this region.

Abstract:Objective To identify the suspected food, pathogenic factors and risk factors of the foodborne disease outbreak in a school, and to provide reference for the prevention, control and investigation of similar events in the future. Methods Descriptive epidemiological method were used to analyze the clinical characteristics, epidemiological characteristics and related risk factors of the cases. Suspicious meals and food were identified by case-control study. Samples such as anal swabs of cases and kitchen workers, reserved food and environment were collected for etiological detection. Salmonella isolates were classified by pulsed field gel electrophoresis. Results A total of 74 cases were found, with an incidence rate of 1.9%. The main clinical symptoms were diarrhea (83.8%), abdominal pain (78.4%) and fever (63.5%). The prevalence curve showed intermittent homologous exposure, and the distribution of cases in classes and dormitories showed no obvious aggregation. Results of a case-control study showed the risk factor was the rice with scrambled egg from the second dining hall (October 8 OR=7.00,95%CI: 1.51~32.48; October 9 OR=262.50, 95%CI: 22.21~3 102.06). A total of 76 samples were collected, 12 of which were isolated and cultured for Salmonella enteritidis. There are two zonal types with similarity of 95.7% by PFGE analysis. Conclusion This incident was a foodborne disease outbreak caused by Salmonella enteritidis, and suspected food was the rice with scrambled egg. Food hygiene supervision should be strengthen in schools and other collective units, and food with eggs should be thoroughly cooked.

Abstract:Objective As one of the common mycotoxins in the food, deoxynivalenol (DON) poses multiple health risks. Limited information is available on DON exposure in Chinese pregnant women who they are vulnerable to various pollutants exposure hazards. The purpose of this study was to detect urine DON concentrations and estimate dietary DON intake in Chinese pregnant women, and provide evidence for assessing the risk of dietary DON exposure for pregnant women. Methods The study involved 103 pregnant women from the Tongji birth cohort study in Wuhan, China. Urine samples were collected and dietary investigation was conducted using food-frequency questionnaire (FFQ). The level of DON in urine was determined by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Results Among 103 pregnant women, total DON was detected in 95 urine samples (92.23%,95/103), free DON was detected in 76 samples (73.79%,76/103). The mean total DON levels were 19.12 ng/mg creatinine for both trimesters, 15.17 ng/mg creatinine for the first trimester and 20.91 ng/mg creatinine for the second trimester. The dietary DON intake for pregnant women was 0.45-0.89 μg/(kg b.w.·d). The dietary DON intake of 11.65%-22.33% pregnant women exceeded current guidance regarding the provisional maximum tolerable daily intake (PMTDI) for DON. The diet of pregnant women was mainly rice and its products, and its intake was positively correlated with the concentration of DON. Conclusion In this study, the detection rate of DON in the urine samples of pregnant women in Wuhan was high, but the level of DON was low. Future attention should be paid to the exposure level of pregnant women to DON and the potential health risks to both mother and fetus.

Abstract:Objective To evaluate the dietary exposure level of aluminum and its potential health risk among adult residents in Qinghai Province. Methods In this paper, the aluminum content of 499 samples of 7 kinds of main aluminum containing foods in Qinghai Province from 2015 to 2020, the Fifth China total dietary study and the food consumption data of nutrition and health monitoring of Chinese residents from 2010 to 2013 were used. The exposure level and potential risk of dietary aluminum in different age and sex groups of residents in Qinghai Province were evaluated by point evaluation method . Results The average content of aluminum in 7 kinds of main aluminum containing foods was 72.210 mg/kg, and the maximum was 1 220.000 mg/kg. The total detection rate was 77.96% (389/499), and the total over standard rate was 19.72% (57/289), among which the detection rate and over standard rate of instant jellyfish were 100.00% (11/11) and 90.91% (10/11) respectively. The average daily exposure of aluminum was 0.080 mg/(kg·d), accounting for 27.86% of the weekly provisional tolerable intake (PTWI). The contribution rate of cereals and their products was the highest, reaching 88.07%. Among the adult residents of different age and gender groups, the daily aluminum exposure of women aged 60 and above was the highest, with an average of 0.086 mg/(kg·d), accounting for 30.05% of PTWI. The median and average dietary aluminum exposure were both less than 1 of the PTWI. Conclusion The health risk of dietary intake of aluminum among adult residents in Qinghai Province was low, and cereals and their products were the main contribution foods.

Abstract:Objective The paper mainly summarizes standards on method of analysis related to foods for special medical purposes(FSMP) in China. Methods The compliance and applicability of the analytical method in national food safety standards were analyzed, compared with the limits for FSMP. Results The valid analytical method standards can basically match the requirements for the limits of FSMP, mainly refers to GB 5009, GB 5413 and GB 4789 series. Individual standard method were not applicable or missing. Conclusion China has basically established systematic framework of standards on method of analysis applicable to FSMP, which can effectively supports the production and supervision. It is suggested that the unique procedure requirements of FSMP should be considered in the standard method drafting process. The paper also suggests future directions for the standards.

Abstract:Objective To investigate Scleroderma cepa poisoning incident on September 4^th 2019 in Chuxiong County, Yunnan Province, analyze the causes of the incident and summarize the clinical experience, and to provide reference for the treatment of mushroom poisoning. Methods Data collection, epidemiological investigation, morphological and phylogenetic identification were taken to analyze the poisoning event. Results Two patients complained of abdominal pain, nausea, vomiting, diarrhea with hypotension 0.5-1 h after ingesting the poisonous mushrooms, who were discharged after symptomatic treatment. The mushroom was identified as Scleroderma cepa by morphological and phylogenetic identification. Conclusion This incident was a mushroom poisoning caused by accidental ingestion of Scleroderma cepa, which was similar to edible Scleroderma yunnanense. As most mushroom poisoning cases were resulted from the consumption of poisonous mushrooms which were very similar to edible mushrooms in morphology, it is recommended not to collect and eat wild mushrooms.

Abstract:Objective To investigate and analyze the epidemiological characteristics of a wild mushroom poisoning event in Qinhuangdao City, identify the species of poisonous mushroom, summarize the experience of investigation and treatment, and put forward prevention and control measures, and provide reference for the treatment and prevention of wild mushroom poisoning patients. Methods The poisoning events were analyzed by using the method of epidemiological investigation, morphological identification and mushroom toxin detection. Results Four villagers in Qinhuangdao city had nausea, abdominal pain, diarrhea, sweating and shivering after eating wild mushrooms. Patients were treated with vomiting, gastric lavage, atropine and other symptomatic treatment in the hospital, and the prognosis of the patients was good. After morphological identification and toxin detection, it was determined that food poisoning caused by mushroom of inocybe. Conclusion This is the first reported poisoning event caused by mushroom of inocybe in Hebei Province. The reason of poisoning was misguided by the Internet and poor self-awareness of food safety. Therefore, publicity and education should be strengthened, enhancing the awareness to prevent the poisoning of wild mushroom.

Abstract:Objective To investigate an incident of mushroom poisoning in Chenzhou, Hunan province in June 2020, analyze the cause of the incident, and provide a basis for formulating prevention and control measures. Methods Epidemiological investigation was carried out to find the cause of poisoning. The samples of suspicious poisonous mushroom were collected for morphological identification, and the mushroom toxin and blood samples were determined by LC-MS. Results There were 7 cases of mushroom poisoning and 1 death. All the patients ate wild mushrooms picked up by themselves, and the incubation period was 14-23 h. Early clinical manifestations included vomiting, abdominal pain, diarrhea and other gastrointestinal symptoms, which led to progressive liver damage and death in severe cases due to acute liver failure. Blood biochemistry showed abnormal elevation of alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase. The remaining wild mushrooms collected on site were identified as Amanita fuliginea by morphological identification and mushroom toxin test. Conclusion This was a mushroom poisoning incident caused by the accidental ingestion of highly toxic Amanita fuliginea. Publicity on mushroom poisoning should be strengthened. Rapid screening technique of mushroom toxin and Foodborne Disease Surveillance Network should be improved to reduce the incidence of mushroom poisoning and death.

Abstract:Objective An epidemiological investigation and analysis of a food poisoning incident at a school in Pudong New Area was conducted to identify the pathogenic factors, pathogenic food and the source of contamination, and to taken effective control measures and provided reference for the disposal of similar incidents in future. Methods A descriptive epidemiological method was used to analyze the epidemiological characteristics of the incident; a case-control study was used to analyze the suspicious food; interview and on-the-spot investigation were used to conduct food hygiene investigation to understand the process of food production, transportation, storage and raw material sources; samples of anal swabs, food, processing links and drinking water were collected for laboratory testing. Results Fifty-one suspected cases were found, and the clinical manifestations were mainly diarrhea, fever, abdominal pain, headache, nausea and vomiting. The incubation period of onset ranged from 2.5 to 5.1 h, with a median of 20 h. The case-control analysis found that the sandwich at breakfast on September 4^th, 2018 was the suspect high-risk food. Salmonella was detected in the samples of anal swab from 7 cases. Molecular typing analysis of the positive strains of Salmonella by pulsed field gel electrophoresis indicated that they were from the same source of infection, and there was a situation of simultaneous infection of multiple types of Salmonella. Conclusion This was an incident of food poisoning caused by Salmonella, and the suspect food was sandwich. It is suggested that school catering units should strengthen the examination of food supply, strictly implement the sample retention system and implement various food safety measures.

Abstract:Bacillus cereus is a common foodborne pathogen that can cause food poisoning in infants, students and adults by contaminating foods such as dairy products, rice, cooked meat and soybean products. The use of accurate and efficient Bacillus cereus detection method is the key to the prevention of foodborne Bacillus cereus disease and food safety quality control. Detection method of Bacillus cereus mainly including bacterial culture isolation and identification, immunological detection and nucleic acid detection. This paper summarizes the core technical features and application examples of each type of detection method , and provides ideas for the development and use of rapid detection method for foodborne Bacillus cereus.