Abstract:Objective The interaction between bisphenol E（BPE） and serum albumin was analyzed to provide a useful referrence for the rapid evaluation of the toxicological effect of bisphenols.Methods Electropherograms of serum albumin with BPE under physiological conditions in vitro were determined using external calibration Hummel-Dreyer （HD） method by capillary electrophoresis. To obtain the interaction parameters， the experimental data were analyzed by three functional forms： Nonlinear equation， Scatchard equation and Klotz equation.Results Three form functions were fitted with the interaction parameters. The binding ratio of BPE and serum albumin was about 2. The interaction parameters showed that two kinds of serum albumin had the same number of binding sites， and the binding between different albumin and BPE were both non-covalent interactions.Conclusion As a simple and effective method， external calibration HD method could be used to analyze the protein pollutant interaction in the food safety field. BPE showed similar moderate interaction with different serum albumin， which suggested that bisphenol compounds had similar pollution distribution regularity in human body and cattle.

Abstract:Objective To prepare proficiency testing samples of Vibrio parahemolyticus （V. parahemolyticus）and apply to laboratory test.Methods The five background strains and V. parahemolyticus were identified by biochemical reaction and matrix-assisted laser desorption ionization time of flight mass spectrometry（MALDI-TOF MS）. The V. parahemolyticus positive samples and negative samples were prepared by freeze-drying. The negative samples contained background bacteria only and the V. parahemolyticus were added in positive samples with background strains. Twenty samples were selected randomly for uniformity test. The samples were stored respectively at -20 ℃ and 4 ℃ to evaluate the storage stability， meanwhile the transport stability were evaluated by storing samples at 25 ℃ and 37 ℃ for 7 d. Samples were distributed to laboratories participating in the proficiency test with operation instruction， and the feedback results from laboratories were analyzed.Results The results of all the related strains were consistent with the expectations. Both of the positive samples and negative samples could meet the requirements of the uniformity and stabilit. The satisfaction rates of assessment results were 87.5% and 90% in 2019 and 2020 respectively.Conclusion The V. parahemolyticus samples could meet the requirements of the proficiency test. By organization proficiency test， the difference of laboratories can be discovered which is helpful to further improve the laboratory test capacity.

Abstract:Objective To clarify the best water cycle sterilization method of canned chestnut in flexible packaging， the effects of different water cycle sterilization and heat sterilization intensity （F） on the sensory quality were explored.Methods When the sterilized temperature and time were the same， the horizontal still water immersion retort， horizontal still water spray retort and horizontal still water shower retort were used to sterilize the canned chestnut in flexible packaging. The heat sterilization intensity （F） of canned chestnut in flexible packaging was calculated by General method， and the influence of different F values on the sensory quality were explored. According to the above determined F， the F in the upper and lower ranges were constructed. When the F was the same， the BALL formula method was used to calculate the sterilized temperature and time of different water cycles， and to explore the effects of different water cycles on the sensory quality.Results When the sterilized temperature and time were the same， the F of horizontal still water immersion retort was 6.2 min， the horizontal still water spray retort was 5.1 min， and the horizontal still water shower retort was 4.9 min. When the F was 5.1 min， the sensory quality evaluation of chestnut was the best. According to F=5.1 min， the ranges of heat sterilized intensity were 3， 4， 5， 6 and 7 min. When the F values were 3~5 min， the sensory quality of chestnut under the three water cycle sterilization processes was positively correlated with the F. When the F values were 5~7 min， the sensory quality of chestnut was negatively correlated with the F.Conclusion When the sterilized temperature and time were the same， the sensory quality evaluation of chestnut after water spray retort was the best. When the F was the same， the sensory quality of chestnut was the best with water spray retort， followed by water immersion retort and water shower retort. In summary， among the three water cycle sterilization process conditions， the chestnut had the best sensory quality after water spray retort.

Abstract:Objective To establish a method to jointly analyze the polysaccharides characteristics， monosaccharide composition and xylitol content of Lycium barbarum.Methods Lycium barbarum polysaccharides were extracted from dried Lycium barbarum fruits by water extraction and alcohol precipitation， and then the extraction rate was calculated. The gel perme-ation chromatography-refractive index-multi-angle laser light scattering method was developed to determine the molecular weight and molecular weight distribution of Lycium barbarum polysaccharides. The extracted Lycium barbarum polysaccharide was hydrolyzed into monosaccharide by trifluoroacetic acid， and a high-performance anion-exchange chromatography-integrating pulse amperometric detection was used to survey and evaluate nine kind of monosaccharides such as arabinose， rhamnose， galactose， glucose， mannose， fructose， xylose， fucose， ribose and one type of xylitol.Results This method was used to detect 10 batches of Lycium barbarum from Ningxia region. It was found that the yield of Lycium barbarum polysaccharide was between 1.86% and 3.21%. The average molecular weight of 10 batches of Lycium barbarum polysaccharides was between 9.12×10⁵～3.65×10⁶ Da. It was found that the order of monosaccharide and xylitol content from high to low was arabinose， glucose， rhamnose， galactose， mannose， fructose， xylitol and fucose in 10 batches of Lycium barbarum detected by ion chromatography.Conclusion This method to determine average molecular weight， monosaccharide composition and content is more comprehensive， objective and accurate than the detection method in the current quality standard. This study may provide technical reference for establishing the quality control method of Lycium barbarum polysaccharide.

Abstract:Objective To detect the adulteration in milk and dairy products， the method for identification of animal derived components in milk and dairy products was constructed.Methods The specific primer probes of cattle， sheep， donkey and buffalo were designed and synthesized. The nucleic acid extraction method in milk and dairy products was optimized. The specificity， sensitivity and applicability of the designed fluorescent PCR method were verified.Results The method had strong specificity and sensitivity for common animal species. The detection sensitivities of cattle， sheep， donkey and buffalo were 0.001， 0.01， 0.01 and 0.01 ng， respectively.Conclusion The specificity， sensitivity， detection limit and other indicators of the constructed method can meet the needs of daily experiments， and provide strong technical support for supervision and testing.

Abstract:Objective To evaluate the efficacy of a polymerase chain reaction （PCR）-based rapid serotyping kit， compare it with traditional serological identification methods， and provide a more efficient and convenient method for serological identification of Salmonella.Methods Fifty nine Salmonella strains were selected from the strain library of our laboratory， and all the strains were typed and identified using the Salmonella serotyping PCR kit and the traditional serum agglutination method， and the coincidence rates of the two typing methods were compared.Results All 59 Salmonella strains were typed by traditional serum agglutination methods， and the typing rate was 100%. All 59 strains were successfully typed by the Salmonella serotyping PCR kit with a typing rate of 100%. The coincidence rate of the two methods was 100%.Conclusion The Salmonella serotyping PCR kit can achieve a high typing rate， greatly shorten the detection time， reduce the workload of routine serotyping and expensive serum consumption， and save costs. It can be used as a rapid serotyping method for Salmonella application.

Abstract:Objective To reveal the effects of specific factors on aflatoxin B₁ （AFB₁） contamination in peanut oil and the status of AFB₁ contamination in peanut oil in Guangdong Province from 2017 to 2018 was taken as an example.Methods A total of 637 peanut oil samples were collected from 21 cities in Guangdong Province from 2017 to 2018， and their labels were recorded. The content of AFB₁ in peanut oil was detected according to “GB 5009.22—2016 Determination of aflatoxin group B and group G in foods”. The temperature data of manufacturing place was obtained from ECMWF Reanalysis v5 database （ERA5） and the average temperature of the month before production was calculated， and the correlation between temperature and AFB₁ content was then analyzed.Results The total detection rate of AFB₁ in peanut oil samples was 65.3% with 24.6% over-standard rate. There was no over-standard sample in the standardized packages， while the bulk samples had a higher over-standard level rate and the median content of AFB₁ was significantly higher than that in the standardized package samples. Among several meteorological factors， average temperature of the month before peanut oil production had a strong relevance to the over-standard rate and content of AFB₁ in the samples. The median content of AFB₁ in bulk peanut oil samples with average temperature of pre-production above 25 ℃ was about 3.5 times that of the samples with average temperature below 22 ℃. However， other meteorological factors showed no correlation with AFB₁ content in peanut oil.Conclusion AFB₁ in bulk peanut oil samples in Guangdong Province from 2017 to 2018 has a high over-standard rate， and the average temperature of pre-production is a key factor affecting the content of AFB₁. Therefore， the government should raise the awareness of the production environment and production process to ensure the quality of bulk peanut oil and reduce the risk of AFB₁ exposure and other risks.

Abstract:Objective To prepare the standard sample for quantitative analysis of okadaic acid （OA） and dinophysistoxins-1 （DTX1） based on the mixed matrix of Pectinidae and Prorocentrum lima.Methods Pectinidae tissue and algae mud of Prorocentrum lima containing OA and DTX1 were used as raw materials. The matrix OA and DTX1 reference materials were prepared by mixing and freeze-drying. The qualitative confirmation， uniformity and stability test and collaborative constant value analysis were carried out.Results It was confirmed that the reference materials contained OA and DTX1. The homogeneity was good by variance analysis （F test）. The long-term stability and short-term stability under simulated transportation conditions were investigated， and the materials performance was stable. The characteristic standard value and uncertainty of OA and DTX1 in the reference materials were （7.039 ± 0.272） mg/kg （k = 2） and （2.012 ± 0.021） mg/kg （k = 2）， respectively.Conclusion The mixed matrix reference material can fill the absence of such reference material in China at present. It can be used for laboratory quality control such as test method verification， test process quality control and capability verification.

Abstract:Objective To develop a method that can quickly determine the absolute content of boron in food by quantitative nuclear magnetic resonance （qNMR） analysis technology.Methods The signal area is directly proportional to the content of boron causing the peak under certain sample-acquired condition. Natural quartz NMR tubes （boron content <0.01×10^-6） was used to eliminate the interference. boron trifluoride etherate was used as an internal standard （δ=0 ppm） in Deuterium Oxide. Signal peak δ=19.38 ppm was set as the characteristic chemical shift of boric acid to pick peaks， integrate， and perform later mathematical operation. Boric acid was extracted from samples with deionized water since its glorious solvability.Results The linearity and the method repeatability of the method were good： y=507.81x+5 597.4， R2>0.999 9. The LODs and the LOQs were 20 and 60 mg/kg， respectively. The recoveries ranged from 90.3% to 102.1%. The precision between days was 1.26%-1.61%.Conclusion There are some good potential application prospects as for its simple pretreatment， quick measurement process， and accurate experimental result.

Abstract:Objective To study the matrix effects （MEs） and the compensation measures of 15 quinolones （QNs） determination in animal derived food by high performance liquid chromatography-tandem mass spectrometry （HPLC-MS/MS） .Methods Fish， pork and chicken as typical substrates were tested by post-extraction spiking method and dynamic multiple reaction monitoring to evaluate matrix effects.Results More than 60% of the quinolones suffered moderate and strong matrix effects in the three samples. Enrofloxacin， pefloxacin and dalfloxacin had strongly matrix enhancement effect， and fleroxacin was strongly inhibited. Pretreatment methods， matrix species， compound species and mass concentration were the main factors affecting the matrix effect of quinolones.Conclusion In the process of daily monitoring which the pretreatment method specified in the test standard cannot be changed casually， matrix matching standard curve， isotope internal standard， diluted sample and improving chromatography resolution combined with dynamic multi reaction monitoring could effectively compensate the matrix effect of quinolones and improve the reliability and accuracy of the detection results.

Abstract:Objective To develop a detection method for rapid screening of carbendazim residues in fruits and vegetables using surface enhanced Raman spectroscopy （SERS） based on the model of probability of detection.Methods The test solution was obtained after ethanol extraction， purification using dichloromethane， nitrogen blowing concentration and ethanol re-dissolution. The parameters including the addition amount of gold nanoparticles， extraction solution， extraction reagent and coagulant were optimized by single factor experiment， and the instrument test conditions of Raman spectrometer were determined.Results The displacement of carbendazim was 630±5 cm^-1， 728±5 cm^-1， 1，002±5 cm^-1， 1，224±5 cm^-1， 1，264±5 cm^-1 and 1，316±5 cm^-1. According to its Raman spectrum characteristic peak and its intensity， carbendazim was determined qualitatively and rapidly. With the probability of detection （POD）， the detection limit of carbendazim in apple， citrus and other fruits was 0.5 mg/kg， and that in pepper and other vegetables was 1.0 mg/kg.Conclusion This method is simple， fast and accurate. It takes only 40 min from sample pretreatment to the results. Combined with POD model， the effectiveness of the method is verified. And the method can be used for field rapid detection of carbendazim residues in fruits and vegetables.

Abstract:Objective A qualitative and quantitative method was established for the simultaneous detection of 60 mycotoxins in nuts and dried fruits.Methods Peanuts and raisins， two typical food substrates rich in fat and sugar， were pre-processed by QuEChERS technique （900 mg MgSO₄， 150 mg PSA， 150 mg C₁₈）， and analyzed by ultra-high performance liquid chromatography-high resolution mass spectrometry （UPLC-Orbitrap/MS） with full scan and data-dependent scanning （dd-MS²） mode. It was qualitatively determined by the retention time and accurate mass of mycotoxins， the chromatographic peak area was quantified， and the fragment ion information was used for confirmation.Results The results showed that the pH value of the extraction solution significantly affected the dissociation state of mycotoxins， which in turn affected the recovery rate. The interference of components such as carbohydrates and lipids in the sample was effectively removed by QuEChERS purification， and the accuracy of qualitative and quantitative analysis was improved. A blank matrix-matched standard curve was used for calibration to reduce the matrix effect and meet the quantitative analysis requirements. The mycotoxins had a good linear relationship within their respective mass concentration ranges （correlation coefficient R²>0.95）， and the recoveries were 60%-120% with relative standard deviation less than 20%. The other seven mycotoxins with R² less than 0.95 can be qualitatively analyzed.Conclusion Compared with the detection method based on triple quadrupole mass spectrometry， the high-resolution mass spectrometry method is easier to quantify， and there is no need to optimize the parent ion， product ion and collision energy for the target one by one，which can effectively reduce the difficulty and time consuming for multi-target analysis. The method has high sensitivity， accuracy and reliable results， and is suitable for the qualitative and quantitative analysis of 60 mycotoxins in nuts and dried fruits.

Abstract:Objective A high-throughput method for simultaneous determination of 67 herbicide residues in oilseeds and oils by liquid chromatography-tandem mass spectrometry combined with dispersive solid phase extraction was established.Methods Peanut， soybean， rapeseed and their oil were extracted with 1% formic acid-acetonitrile， and then purified by ethylenediamine-N-propyl and anhydrous MgSO₄ dispersed solid phase extraction. Methanol and 5 mmol/L ammonium acetate （containing 0.1% formic acid） were used as mobile phases for gradient elution. C₁₈ column was used for separation， positive and negative ion mode of ESI ion source was used for simultaneous multi-reaction monitoring （MRM）. And matrix standard curve external standard method was used for quantification.Results Under different substrates， the linear range of 67 herbicides was from 0.000 5 to 0.08 mg/L， the correlation coefficients （R²） were all above 0.992， and the limits of detection （LODs） were 0.005~0.02 mg/kg. The recoveries of three spiked levels （LOD， 2LOD and 10LOD） were between 62.3% and 118.1% with RSD （n=6） less than 15%.Conclusion This method is stable， specific， sensitive and accurate， and can be used for qualitative and quantitative detection of herbicides in oilseeds and oils.

Abstract:Objective To apply rapid identification of water-injected and gum-injected pork by chemometrics analysis combined with low field nuclear magnetic resonance.Methods 17 variables obtained by low field nuclear magnetic resonance were used to extract principal components by principal component analysis， and 4 principal components were identified by discriminate analysis. A three-layer MLP neural network model with a structure of 17-6-3 was established through constrained optimization modeling using 17 original variables as input， and the types of water-injected pork and gum-injected pork as output.Results In the discriminate analysis model， the discriminant accuracy of cross-validation in the control group， water-injected group and gum-injected group was 60/60， 91/95 and 359/384， and the total correct discriminant rate was 94.6%. In the neural network model， the total correct discriminant rate of 179 samples in the testing set was 97.8%.Conclusion Low-field nuclear magnetic resonance combined with discriminate analysis model and neural network model can effectively distinguish water-injected and gum-injected pork. The method is simple and can be used for rapid detection.

Abstract:Objective A qualitative and quantitative method has been established to rapidly determine carnitine enantiomers in dietary supplement by ¹H-nuclear magnetic resonance combined with chiral lanthanide shift reagents （CLSR-¹H qNMR）.Methods Pyrazine acted as internal standard was added to the samples dissolved in d₄-methanol. After vortexing， ultrasonic-assisted extraction and centrifugation， an appropriate amount of supernatant and chiral lanthanide shift reagent （CLSR） Eu（thfc）₃ were added to the NMR tube for directly determination.Results The linearity range of L-carnitine was 16.3～4 800 μg/mL with correlation coefficient （r）>0.99. The limit of detection （LOD） was 24.5 mg/kg， and the limit of quantification （LOQ） was 73.5 mg/kg. While the linearity range of D-carnitine was 10.6～530 μg/mL with r>0.99. The LOD was 27.5 mg/kg， and the LOQ was 82.5 mg/kg. Recovery rates obtained from spiked samples were between 95.9% and 114.6% with the RSDs （n=6） of 3.31%~6.12%. Tests on capsules， milk tea， coffee powder and tablet from online shopping that claimed to have weight-loss effects failed to detect D-carnitine.Conclusion This method is simple， rapid and sensitive. And the sample test could be completed within 25 min， which could provide a theoretical basis for rapidly detection of carnitine enantiomers.

Abstract:Objective A sensitive and rapid method was developed for the simultaneous determination of L-carnitine and D-carnitine in infant formula by pre-column derivation high performance liquid chromatography， and the key points were explored.Methods Carnitine in sample was extracted with hydrochloric acid， saponified with potassium hydroxide， purified by acetonitrile and solid phase extraction column （SPE） and derivated. The derivative was separated by the C₁₈ chromatography column， detected by UV detector， and quantified by external standard curve.Results The linear ranges of L-carnitine and D-carnitine were 0.2-10 μg/mL with correlation coefficients of 0.999 9 and 0.999 4. The average recoveries of carnitine were 87.14%-96.96% under the 3 spiked concentrations. The limits of detection （LODs） were 0.6 mg/100 g， and the limit of quantification （LOQ） was 2 mg/100 g. The concentration of potassium hydroxide， purification process with SPE， solvent of derivatization reagent and operation in derivation were the key points in this method.Conclusion This method is simple， accurate and is suitable for simultaneous detection of L-carnitine and D-carnitine in infant formula. And there is no significant difference between this method and enzymatic spectrophotometry.

Abstract:Objective A portable high-sensitivity X-ray fluorescence spectrometry method was established to directly and quickly determine the content of arsenic， cadmium and lead in wheat flour.Methods Part of the sample was put into the sample cup， and then directly put the sample cup into the portable high-sensitivity X-ray fluorescence spectrometer for testing. The testing time， sample compactness， and testing thickness of the instrument were optimized and applied to the detection of different types of wheat flour.Results The relative standard deviation （RSD， n=6） of the precision was between 0.6% and 4.8%， and the recovery rate was 78.3%-120.4%. The detection limits of lead， cadmium and arsenic were 0.06 mg/kg， 0.06 mg/kg， 0.05 mg/kg， the quantification limits were 0.19 mg/kg， 0.19 mg/kg and 0.17 mg/kg， respectively. The correlation coefficient of portable highly sensitive X-ray fluorescence spectrometry and inductively coupled plasma mass spectrometry was greater than 0.98.Conclusion The method has relatively high precision， good detection limit and quantification limit， and can meet the requirements of simultaneous rapid detection of multiple heavy metal elements in wheat flour.

Abstract:Objective To establish a detection method for thiourea in wheat flour and flour treatment agents（FTA） by pass-through solid phase extraction purification and high performance liquid chromatography.Methods The samples were extracted by acetonitrile aqueous solution（8：2， V/V）， and purified by PRiME HLB pass-through SPE column. The extract was separated on a XBridge Amide column （4.6 mm×250 mm， 5 μm） with acetonitrile and water as the mobile phase in gradient elution， and detected by high performance liquid chromatography-diode array detector （HPLC-DAD）.Results The linear correlation coefficient （R²） was higher than 0. 9999 in the range of 0.05-20 μg/mL. The limit of detection （LOD） and the limit of quantification （LOQ） were 0.15 and 0.5 mg/kg， respectively. The average recoveries ranged from 95.5% to 103.7% with the relative standard deviation （RSD） less than 5.7% at three spiked levels of LOQ， 2LOQ and 10LOQ.Conclusion The problem of easy gelation and poor dispersion effect of FTA had been solved by the method established in this experiment， while matrix interference in wheat flour and FTA reduced effectively， which protected the chromatographic column. This simple， sensitive， accurate method is suitable for the confirmation and quantification of thiourea in wheat flour and FTA.

Abstract:Objective To develop a method for the determination of nosiheptide residue in food animal tissues （porcine muscle， porcine liver， porcine kidney， chicken muscle， chicken liver and chicken kidney） with high performance liquid chromatography-tandem mass spectrometry （HPLC-MS/MS）.Methods After extracted by 0.1% acidic acetonitrile， the nosiheptide extract was cleaned up by Captiva ND cartridge and determined by HPLC-MS/MS in negative electrospray ionization mode. Quantification was performed using corresponding matrix-matched calibration curves.Results Nosiheptide in corresponding matrix showed good linear relationships （r>0.99） in the calibration range of 2~200 μg/L， and the limit of detection （LOD） and limit of quantification （LOQ） of the method were 2.0 and 7.0 μg/kg， respectively. The recoveries of the method ranged from 76.27% to 92.31% at the spiking level of 3.5， 7.0 and 70 μg/kg with relative standard deviations of 2.15%~8.03%.Conclusion The proposed method is simple， rapid， accurate as well as reproducible and can be applied to monitor and determine nosiheptide residue in food animal tissues.

Abstract:Objective To establish a method for the determination of food additive theaflavins by ultraviolet spectrophotometry.Methods After dissolved in water， the sample solution was extracted with ethyl acetate and 2.5% sodium bicarbonate solution in turn. A certain volume of ester phase was fixed with ethanol， and then it was quantified by spectrophotometry. The maximum absorption wavelength， sample quality， concentration of sodium bicarbonate solution and extraction time by sodium bicarbonate solution were researched.Results Under the best conditions， four theaflavin monomers had good linear relationships within their respective concentration ranges， and the correlation coefficients were all greater than 0.999. The limit of quantitation was 3%， the standard recoveries were 95.2%-108.4%， and the relative standard deviations were less than 5%.Conclusion This method has good repeatability， precision and stability， and is suitable for the determination of food additive theaflavin.

Abstract:Objective To verify the potential food safety hazards and provide a scientific basis for risk assessment， risk management and food safety standards formulation of ready-to-eat （RTE） food in Shanghai.Methods From 2016 to 2020， 10 521 food samples of 20 kinds of RTE foods were collected in Shanghai. A series of qualitative or quantitative detection of two hygienic indicator bacteria and six pathogenic bacteria， including the aerobic plate count （APC）， Escherichia coli （E.coli） count， Vibrio parahaemolyticus （V. parahaemolyticus）， Staphylococcus aureus， Diarrheagenic E. coli， Salmonella spp.， Bacillus cereus （B. cereus）， and Listeria monocytogenes （L. monocytogenes） were conducted. and the correlation between them was analyzed.Results The highest average APC count of cold rice noodle products， salad and Chinese salad were （5.13±1.43）lgCFU/g， （4.56±1.13）lgCFU/g， （4.26±1.75）lgCFU/g， and the E. coli count were （1.20±1.00）lgCFU/g， （1.47±1.41）lgCFU/g and （1.18±1.06）lgCFU/g. The positive rates of L. monocytogenes in cold pot skewers， salad， Chinese salad and cooked meat products were relatively high （6.27%， 3.36%， 2.71% and 2.69%， respectively）. V. parahaemolyticus was only detected in three categories， including 3.65% of raw animal aquatic products， 2.58% of Chinese salad and 0.42% of cooked meat products. The positive rate of B. cereus in rice noodle products was 7.51%， which was significant higher than sushi， whose rate was 0.53% （P<0.05）. The APC level was positively correlated with the E. coli count （P<0.001） and the positive rate of foodborne pathogens （P<0.05）.Conclusion Raw food， salad， sandwich and other RTE foods without further heating had the highest level of hygiene indicator bacteria and foodborne pathogens， which indicated a high risk of foodborne disease which should be the focus of prevention. There was a positive correlation between the average APC level and the positive rate of foodborne pathogens in solid RTE foods.

Abstract:Objective To provide the scientific basis for the prevention and control of diarrheagenic Escherichia coli （DEC） infection， the epidemiological characteristics of DEC infection in Shanghai was identified.Methods The epidemiological information of the collected diarrhea cases and the DEC test results from 30 foodborne disease surveillance sentinel hospitals in Shanghai from 2018 to 2020 were analyzed by the descriptive epidemiological methods.Results According to the result of 13 672 infectious diarrhea cases and specimens， the positive rate of DEC was 5.71% （781/13 672）， mainly ETEC and EAEC. The highest positive rate of DEC was often associated with child below the age of 7 and the farmers， and the highest positive rate of DEC was occurred between July and September. Compared with other patients， the positive rate of DEC in patients with fever and no vomiting or diarrhea 3-9 times/d was significantly higher. The positive rate of DEC was relatively high in cases with suspected food category of fruit and its products.Conclusion ETEC and EAEC were the main virulence genotyping of DEC in Shanghai， and the peak of DEC infection occurred in summer. Specific clinical symptoms could play as indications for clinical diagnosis and treatment. The supervision and management of catering service industry and street food should be improved， and the publicity and training of public food safety awareness and good food safety habits should be strengthened.

Abstract:Objective To provide a reference for food safety risk assessment and safety assurance for the Winter Olympics and Beijing residents， the exposure level and possible health risks of cadmium （Cd） in main foods in the surrounding areas of the 2022 Beijing Winter Olympics were evaluated. Methods Based on the hazard assessment and limit standard analysis of cadmium， the point assessment method was used to assess the dietary exposure risk of cadmium. The 2019 to 2020 on-site sampling survey data of an urban area of Beijing and Zhangjiakou Chongli area and the 2018 Beijing main food consumption survey data were used in this pre-assessment. Results The cadmium provisional tolerated monthly intake （PTMI） established by joint FAO/WHO Expert Committee on Food Additives （JECFA） was 25 μg/kg·BW. The overall average content of cadmium in various foods was 0.010 6 mg/kg， and the overall rate of exceeding the standard was 0.47%. The average exposure of Beijing residents to cadmium through the main food was 5.92 μg/（kg·BW·m）， accounting for 23.66% of the JECFA-recommended provisional tolerable monthly intake （PTMI） of 25 μg/kg·BW. In addition， cereals and vegetable foods were the main sources of dietary cadmium exposure. According to the current limit of cadmium （LOC） in GB 2762—2017 National Food Safety Standards Limits of contaminants in food， except for these two categories of food， the theoretical exposure to cadmium in the rest of the food did not exceed the PTMI. The estimated LOC for vegetables， grains and cereals is 0.172 and 0.199 mg/kg， both of which were less than the maximum limit value stipulated by the national standard. Conclusion The main food cadmium exposure of Winter Olympics and Beijing residents is generally at a safe level， and the health risk is relatively low.

Abstract:Objective To understand the potential harm and influencing factors to the health risk of residents through the exposure of nitrite in cooked meat products in S district of Beijing.Methods The nitrite contents in 535 cooked meat samples in S district from 2013 to 2019 was monitored by spectrophotometry， the food consumption of meat products at different ages in S district were collected through nutrition survey. Compared with the acceptable daily intake （ADI） of 0.07 mg/kg·BW established by the joint FAO/WHO Expert Committee on Food Additives （FAO/WHO JECFA）， the health risk of nitrite dietary exposure was analyzed.Results The detection rate of nitrite in cooked meat products sold in S district of Beijing was 94.02%， and the violation rate was 9.16%. The daily exposure of nitrite from cooked meat products for people over 2 years old ranged from 0.000 0 to 0.390 0 mg/kg?BW， the average nitrite exposure was 0.018 8 mg/kg·BW， and 2.5 % of the residents exceeded the ADI. Except 50~64 years-old group and ≥80 years-old group， the daily exposure of nitrite from cooked meat products exceeded the ADI. Daily exposure of nitrite from cooked meat products in 2~5 years-old group and 6~12 years-old group exceeded ADI at P₉₅ percentile，which was at an unacceptable level. The daily exposure of nitrite from cooked meat products in the 13~17 years-old group was equal to ADI at P₉₅ percentile.Conclusion Nitrite residues in cooked meat products sold in S district had the risk of chronic toxicity in some population. Supervision and sampling efforts should be strengthened to popularize nitrite-related knowledge to the public， and minimized the addition of exogenous nitrite and the production of endogenous nitrite.

Abstract:Objective To investigate the current situation of food safety knowledge， attitude and behavior （KAP） among professional technicians in food microbiology laboratory in China and explore the influencing factors， so as to provide the reference for improving their comprehensive ability.Methods A questionnaire survey of food safety KAP covering 15 provinces in China was conducted among professional technicians in food microbiology laboratories subordinate to provincial， municipal and district （county） government departments and food microbiology laboratories of non-governmental organizations such as third-party institutions and enterprises， and the results were analyzed using statistical methods.Results A total of 1 505 questionnaires were collected and 1 386 were valid with an average score of 0.63 ± 0.14. Except for gender and the time of recent training， there were significant differences in the food safety KAP scores at different ages， academic qualifications， years of employment， professional background， department subordinated， administration levels， region where the lab was located and usual training form. A positive correlation had been found among knowledge， attitude and behavior scores.Conclusion Although some professionals got full marks， the average score was only slightly higher than the qualified level. The results of statistical analysis suggested that some professionals such as new recruits and professional technicians with lower academic qualification should pay attention to the improvement of food safety knowledge and accumulation of work experience， so as to constantly improving their professional skills. The comprehensive knowledge on food safety of technicians from laboratory at municipal and district （county） levels should also be strengthened. The technical trainings in the form of on-site training were suggested.

Abstract:Objective To study the ideology within Hazard analysis and critical control point（HACCP） system， the relationship between ideology and HACCP system as well as between those ideologies.Methods The discipline idea contained in HACCP system were determined by investigating the connection between HACCP system and disciplines. The top six disciplines related to HACCP system were determined by expert scoring method. The correlation and significance were analyzed by Eviews software to determine significant discipline. The ideas within HACCP system and the relationship between HACCP system ideas were studied through brainstorming method.Results The results showed that the subjects of food， management， mathematics， philosophy， computer and agriculture were correlated to HACCP system. Management， mathematics， philosophy and HACCP system were correlated significantly. Management， as the basis of HACCP system ideological framework， would put more focus on researches based on management theory and method extension. Mathematics， as significant tool of HACCP system research， would put more focus on analysis methods research based on mathematics， such as statistics， probability， model and so on. Philosophy， as ideology framework as HACCP system， would put more focus on ideology and view researches based on philosophy.Conclusion HACCP system contains ideologies of management， mathematics and philosophy. Management is the foundation level as the basic framework of HACCP system. Mathematics is intermediate level， as the basic theory research tool of HACCP system to support further basis research. Philosophy is the highest level as the internalized ideology of HACCP system basis theory， the ideology research of which provides scientific proof for future HACCP system theory and management research.

Abstract:The market-oriented management of salt need to constantly improve the relevant laws and regulations， and explore better safety supervision model. The current situation of salt safety supervision in China is introduced. The existing problems of salt safety supervision in China are analyzed based on policy and reality. The countermeasures and suggestions for establishing a new long-term mechanism of salt safety supervision are put forward.

Abstract:Objective To study the influence of caregivers on their children’s ability to avoid food safety risks， so as to provide reference to empower the caregivers to participate food safety social co-governance.Methods A total of 5 611 rural families were selected from 7 provinces/autonomous regions by stratified random sampling， and factors of caregivers influencing rural children’s ability to avoid food safety risks were examined by ordered probit model.Results Children taken care by grandparents showed significantly stronger ability to identify unsafe foods than by parents. Compared to children taken care by parents， the percentage of children taken care by grandparents who had strong ability to avoid food safety risks was higher by 6.94%， while the percentage of children who had moderate and low ability was lower by 6.48% and 0.46%， respectively. In addition， the neglecting parenting attitudes of caregivers significantly increased children’s acceptance on unsafe foods.Conclusion The influence of rural caregivers on children's ability to avoid food safety risks was complex. Caregivers type， parenting attitudes and the ability to avoid food safety risks affect children's ability to avoid food safety risks significantly. It is suggested that the government should launch food safety risk communication toward rural caregivers to promote food safety social co-governance.

Abstract:Objective The epidemiological characteristics of foodborne disease outbreaks in Chinese Mainland in 2021 were analyzed to provide scientific basis for further prevention and control strategies.Methods The epidemiological characteristics of outbreaks of foodborne disease data collected by National Foodborne Disease Outbreaks Surveillance System were analyzed by descriptive statistics.Results A total of 5 493 foodborne disease outbreaks were reported， resulting in 32 334 illnesses and 117 deaths from 30 provinces （autonomous regions and municipalities） and Xinjiang Production and Construction Corps， excluding Xizang （Tibet） Autonomous Region. Among 3 275 outbreaks with a single confirmed etiology， microbial pathogens were the most common cause of outbreaks， accounting for the largest illnesses（53.05%， 11 585/21 839）.Poisonous mushroom caused the largest percentage of outbreaks and deaths，accounting for 49.13%（1 609/3 275）and 67.86%（76/112）respectively.Among the location of foodborne disease outbreaks， private homes accounted for 54.00% of the outbreaks （2 966/5 493） and 92.31 % of the deaths （108/117）. Food service settings had the largest number of illnesses（65.59%， 21 208/32 334）.Conclusion Poisonous mushrooms caused the largest number of deaths， mainly occurred in private homes. Microbial pathogens remained the main pathogenic factors in restaurants and school canteens. The supervision and management of food safety， health education and medical treatment according to the characteristics of different types of food poisoning incidentsshould be taken in high-incidence seasons， high-incidence areas and key location.

Abstract:Objective To study the epidemiological characteristics of foodborne disease outbreaks in Chinese Mainland in 2018.Methods The 2018 annual foodborne disease data collected by National Foodborne Disease Outbreaks Surveillance System were analyzed by descriptive statistical analysis.Results A total of 6 537 foodborne disease outbreaks were reported in 31 provincial-level administrative divisions， which caused 41 750 illnesses and 135 deaths. The outbreak of foodborne diseases in families caused 80% of deaths， the number of events and deaths caused by poisonous mushroom was the largest， accounting for 25.13% and 37.78% respectively. The number of illnesses caused by microbial factors was the largest， accounting for 29.28%.Conclusion The family is an important place caused the deaths of foodborne disease outbreaks， especially the eating habits with regional and local characteristics， such as wild mushrooms. Microbial foodborne disease are important food safety problems in China. Vibrio parahaemolyticus and Salmonella spp. are the most common foodborne microorganisms. Poisoning caused by metabolites of pathogenic bacteria （such as rice yeast acid） needs pay attention to.

Abstract:Objective To analyze and master the epidemiological characteristics and pulsed-field gel electrophoresis （PFGE） typing of Campylobacter in diarrhea patients in Haidian District of Beijing from 2018 to 2020.Methods Stool samples of 756 diarrhea patients were collected in 3 hospitals from 2018 to 2020. Campylobacter was isolated and identified， the isolated 25 Campylobacter strains were analyzed by PFGE for genetic typing.Results The total detection rate of Campylobacter was 4.37% （33/756）， of which the detection rates of Campylobacter jejuni （C. jejuni） and Campylobacter coli （C. coli） were 3.04% （23/756） and 1.32% （10/756）， respectively. Epidemiological characteristics regarding the heterogeneities of Campylobacter showed no significant differences among different gender， age， and occupation. 48.48% （16/33） diarrhea patients experienced acute watery diarrhea， and they usually have a fever. The peak of detection rate sustained from May to July. Meat and meat products were recognized as a primary source of food-related transmission of Campylobacter to human. 16 and 7 patterns were detected through PFGE in C. jejuni strains and C. coli strains， respectively.Conclution Campylobacter contamination deserved more attention. This study fills the data gap of Campylobacter infection in diarrhea patients in Haidian District of Beijing， and provides references for the prevention and control of foodborne diseases in Haidian District.

Abstract:Objective To understand the dietary structure and nutrient intake of urban residents in 3 cities， food consumption in Jiangxi Province was investigated in 2019.Methods A multi-stage stratified cluster random sampling method was used to select 1 251 residents from 362 households in Xinjian district of Nanchang City， Jinggangshan City of Ji’an City and Lianxi district of Jiujiang City. The dietary survey adopted a combination of family weighing method and non-continuous 3 d 24 h review inquiry method to collect food consumption data and the intake of various foods and nutrients per standard person per day was calculated.Results The urban residents in Jiangxi Province consumed excess livestock and poultry meat， oil and salt， the intakes per standard person per day were 111.70， 31.06 and 7.78 g， respectively. The intakes of vegetables， fruits， eggs and dairy products， were 240.53， 47.97， 27.91， 26.31 g， respectively. The intake of cereals and tubers and aquatic products were 398.30， 42.95 g， respectively. Moreover， the percentages of energy from protein， fat and carbohydrates were 14.68%， 33.74% and 51.50%， respectively. The daily intakes per standard person of dietary calcium， vitamin A， thiamine， riboflacin and vitamin C were lower than the estimated average requirement， which accounted for 89.74%， 72.41%， 89.04%， 82.85% and 60.21%， respectively. 74.18% of the sodium intake of residents exceeded the appropriate intake by more than 100%.Conclusion The energy and protein intake of urban residents of Jiangxi Province basically met the dietary requirements， while the fat energy supply ratio was high， the carbohydrate energy supply ratio was low， and the intake of some nutrients was insufficient or excessive. Furthermore， the intake of vegetables， fruits and milk was inadequate. It is recommended to continuously to strengthen the education of dietary nutrition knowledge and encourage residents to have a reasonable diet.

Abstract:Molecular imprinting technology is a kind of technology that simulates the interaction between enzyme - substrate or antibody - antigen and synthesizes artificial receptors with specific recognition performance using target as template. In the early stage， the research objects were mostly small organic molecules including pesticides and veterinary drugs， and biological macromolecules including proteins. In recent years， researches have been extended to super-large "molecules" -cells， especially bacterial imprinting with a broad application prospect in the field of rapid detection of pathogenic bacteria. This paper introduces the principle of molecular imprinting technology， the selection of bacterial imprinting template and the preparation method of imprinted polymers. The application of molecular imprinting technology in the detection of pathogenic bacteria is summarized. Finally， the application prospect of molecular imprinting technology in the detection of pathogenic bacteria is discussed.

Abstract:Salmonella is a foodborne pathogen widely existing in nature， which can cause human food poisoning， gastroenteritis， septicemia and other diseases， seriously endangering human health. Therefore， rapid and accurate detection methods for Salmonella are important to prevent and control Salmonella disease. The immunological technology， molecular biology technology and biosensor technology in the application of detecting foodborne Salmonella are analyzed in this paper. Advantages and disadvantages of different detection techniques are expounded to offer reference for developing rapid detection methods of foodborne Salmonella.

Abstract:Staphylococcus aureus is a common foodborne pathogen， which can cause food poisoning by polluting foods rich in protein or starch， such as dairy products and meat products， and it is also tend to cause local suppurative infection， pneumonia， pericarditis and even septicemia in severe cases. Accurate and efficient detection methods of Staphylococcus aureus are significant to improve food safety and quality control by avoiding food poisoning. The detection methods of Staphylococcus aureus are mainly immuno-serological technology， polymerase chain reaction technology and biosensor technology and others. In this paper， the technical characteristics and application examples of detection methods are summarized respectively to provide reference for the development and application of rapid detection methods for foodborne Staphylococcus aureus.