Abstract:This article reviews the past and current Chinese national food control system, food safety standard system and the application of risk analysis framework and provides some future perspectives. The national food control system in China has been changed from single ministry to fragmented management by multiple ministries and in the current system the State Administration of Market Regulation (SAMR), the General Administration of Chinese Customs (GACC) and Ministry of Agriculture and Rural Affairs (MOA) have the main responsibility. In the same time, the Food Hygiene Law was changed to Food Safety Law based on the risk analysis framework. Three different and conflicted mandatory national food standard systems were merged into one national food safety standard system by the end of 2015. The new standard system is in line with the Codex system and is significantly improved in coverage, scientific basis and feasibility. The application of risk analysis framework was advanced from lack of awareness to basic understanding and recently to primarily application. Significant progress was made in national food contamination monitoring and foodborne disease surveillance, risk assessment and risk communication. However, it should be noted that there are still many food safety issues in China. Surveillance and control on microbial foodborne illness are still weak. Food fraud is quite common at present. Risk communication is facing great challenge. In order to improve the quality and safety of Chinese food products, emphasis should be put in safety assurance of the whole food chain by industry and seamless inspection and control by regulatory agencies.

Abstract:On the 70th anniversary of the founding of the People's Republic of China, the author reviewed comprehensively the process and effectiveness of the development of food safety risk assessment system in China. Following the requirement of implementation of President Xi's words regarding to the most rigorous standards and of ‘remaining true to our original aspiration, keeping our mission firmly in mind, finding the gap and taking the responsibility’, the author explored deeply the existing problems based on the extensive investigation and information collection. Focusing on Opinions of the CPC Central Committee and State Council on Deepening Reform and Strengthening Food Safety, the author also proposed the future strategies for national risk assessment system, which may provide recommendations for scientific development of food safety risk assessment system and bring into play to food risk control of risk assessment roles in China.

Abstract:Objective To evaluate reproduction toxicity of GmDREB3 gene modified wheat in Wistar rats. Methods One hundred and eighty specific pathogen free healthy Wistar rats were randomly divided into basic food control group,non-Gm wheat group and Gm wheat group,with 30 male and 30 female in each group, fed with AIN 93 diet, non-Gm wheat and Gm wheat, respectively. After 13 weeks, the rats mated with the same group and produced F1 baby rats. The following indexes were analyzed:the toxic manifestations of the F0 and F1, body weight, food utilization ratio, female hormone level, pathological changes of reproductive organ, viscera coefficient, the ratio of liver and brain, the ratio of spleen and brain, the reproduction indexes of F0. Body weight, body length, tail length, pathological changes of nerve on post natal day 21 (PND21) and immunological index on post natal day 56 (PND56), including lysozyme (LYS), diamine oxidase (DAO), secretory immunoglobulin A (sIgA) and immunoglobulin E (IgE), were examined in F1 female rats. Results Compared with non-Gm groups, the liver coefficient decreased(P<0.01), spleen coefficient increased(P<0.05)and the ratio of spleen and brain increased(P<0.01)in F0 male rats, tail length of F1 rats in Gm wheat group were decreased(P<0.05)on PND0, PND4, PND7 and PND21. The other indexes in Gm wheat group rats had no obviously difference. ConclusionGmDREB3 gene modified wheat has no reproductive development toxicity in rats.

Abstract:Objective To detect the genotoxic effects of long-term administration of nano zinc oxide nanoparticles (ZnO NPs) particles on rats by using the alkaline comet assay in vivo. Methods In combination with the extended generation reproductive toxicity test, 13-week-old parental SD rats were administered orally with ZnO NPs at 0,7, 50, and 350 mg/kg (maximum concentration of the nanoscale dispersion), and body weight changes were recorded and observed. After 70 days, 10 male rats and 10 female rats were taken from each dose group and sacrificed. Ethylene diamine tetraacetic acid anticoagulated whole blood was taken from each rat. The comet assay kit was used for tableting, and the result of comet analysis were analyzed by quantitative analysis software (Casp). Results Compared with the vehicle control group, peripheral blood DNA damage cell rate and tail DNA of the high-dose group of male rats increased significantly, which were 28.60% and(36.38±5.84)%, respectively (P<0.05). Peripheral blood DNA damage cell rate and tail DNA of the high-dose group of female rats increased significantly, which were 27.31% and(18.80±2.96)%, respectively (P<0.05). Conclusion The result of alkaline comet assay in ZnO NPs were positive at 350 mg/kg group.

Abstract:Objective To investigate the radioprotective effect of jackfruit oligopeptides (JOPs). Methods One hundred and forty-four specific pathogen free(SPF)female BALB/c mice were randomly divided into blank control group, model control group, whey protein group (0.40 g/kg BW) and 3 JOPs intervention groups (0.20,0.40,0.80 g/kg BW) with 24 in each group. Each group was randomly divided into 3 subgroups, 8 per subgroup. On the 14th day of the intragastric administration, the mice except the blank control group received ⁶⁰Co γ-ray whole body irradiation, and intragastric intervention continued after irradiation. The first subgroup of each group (8 Gy, 1 Gy/min) was subjected to 30 d survival test, and the other two subgroups (3.5 Gy, 1 Gy/min) were used to detect peripheral blood white blood cells (WBC), bone marrow DNA content, weight changes and organ indexes of liver, spleen and thymus on the 3rd and 14th day after irradiation, respectively. Results Compared with the model control group, the survival time of the medium and high dose group of JOPs was significantly prolonged(P＜0.05). On the 3rd and 14th day after irradiation, the WBC number, the DNA content of bone marrow cells, the liver and spleen indexes in the JOPs intervention groups were significantly increased(P＜0.05). Besides, the thymus index of the low and middle dose groups of JOPs increased significantly on the 14th day after irradiation(P＜0.05). Furthermore, the efficacy of JOPs was superior to those of whey protein. Conclusion JOPs had protective effects against ionizing radiation exposure.

Abstract:Objective To establish and evaluate a duplex polymerase chain reaction(DPCR)system of species-specific tlh gene and typical virulence gene (tdh1_368) of Vibrio parahaemolyticus (VP). Methods The DPCR system was evaluated by single blind method for specificity and sensitivity, and the field methodological evaluation was carried out by artificially contaminated samples, diarrhea fecal samples and aquatic products. Results The developed method had high specificity (100%) and high sensitivity (≥1.5 ng/μl). No significant difference in the VP positive rate of diarrhea samples and aquatic products detected by this method and culture method. This method confirmed that the VP epidemic strain within diarrhea samples was 93.5% (29/31)；DPCR could report VP epidemic clones within 24 hours with diarrhea specimens and 4-8 hours after enrichment of artificially contaminated samples. Conclusion DPCR combined with routine bacterial enrichment method could shorten the reporting time of monitoring and processing time of emergency samples, DPCR could help improve the prediction, early warning and traceability of VP epidemic clones, and improve the efficiency of public health disposal and control.

Abstract:Objective To understand the contamination, molecular typing and drug resistance characteristics of Cronobacter in infants and young children foods in Jiangxi Province in 2018, and to provide reference data for infants and young children foods safety supervision, and clinical medication. Methods 337 commercially available infants and young children foods were collected, Cronobacter was isolated and identified according to GB 4789.40-2016 by matrix assisted laser desorption ionization-time of flight mass spectrometry(MALDI-TOF MS). The drug resistance test was performed on isolated strains via the broth microdilution method. Pulsed field gel electrophoresis(PFGE)was used to confirm the molecular type. Results Cronobacter was not detected in 168 infants and young children formulas; 24 Cronobacter isolates were isolated from 169 infants and young children cereal-based complementary food, with a positive rate of 14.2%. There was no difference in positive rate between rural and urban samples among the four seasons. Among the 13 antibiotics tested, 24 isolates were resistant to 8 kinds of antibiotics. The highest resistance rate was cefazolin (62.5%,15/24) and trimethoprim/sulfamethoxazole (29.2%,7/24). All isolates were sensitive to ciprofloxacin and imipenem. Besides, one isolate was resistant up to seven kinds of antibiotics. The result of PFGE showed that there were 22 molecular types in these isolates, and the similarity ranged from 46.6% to 100.0%. Conclusion The contamination of Cronobacter in infants and young children foods in Jiangxi Province in 2018 was similar to that in some parts of China,Cronobacter were prevalent in cereal-based supplements for infants and young children. Cronobacter isolates were not sensitive to the first and second generation cephalosporins, and PFGE molecular type of most isolates was highly diverse.

Abstract:Objective To investigate the prevalence, antimicrobial susceptibility, and genetic characteristics of Staphylococcus aureus from ready-to-eat meats in Hefei. Methods Five hundred and fifty ready-to-eat meats samples were collected from supermarkets and open vegetable markets in Hefei. All samples were subjected to qualitative and most probable number (MPN) analysis for S.aureus according to the National Food Safety Standard Food Microbiological Examination:Staphylococcus aureus (GB 4789.10-2016). Antimicrobial susceptibility of all isolates was evaluated using the Kirbye-Bauer disk diffusion. The sequence types (ST) of S.aureus were performed via multilocus sequence typing (MLST), and phylogenetic tree was constructed by MEGA 7.0 software. Results In total 744 samples, 4.2% (31/744) were positive for S.aureus, of which the most contaminated foods were stewed meat(8.1%, 15/185)followed by roast (6.3%, 11/174). Most probable number (MPN) analysis showed that 90% of the samples were ranged in 0.3-＜10 MPN/g. The result of antimicrobial susceptibility analysis showed that 80.6% (25/31) of the isolates were resistant to penicillin G, more than 40% of the isolates were resistant to streptomycin, erythromycin and kanamycin, and 61.3% (19/31) isolates were multidrug resistant. In addition, 8 sequence types (ST6, ST7, ST15, ST59, ST72, ST188, ST398 and ST2196) were obtained by multilocus sequence typing, and ST188 and ST72 were the main genotypes. Conclusion S.aureus contamination exists in stewed meat and roast meat in Hefei, and the ratio of multi-drug resistant strains was high, which had potential threat to the health of consumers.It was necessary to continuously monitor the contamination rate, bacterial resistance and genotype epidemic trend, and improve the risk assessment of foodborne S.aureus infection in the region.

Abstract:Objective To establish a new accurate quantitative method for detection of Vibrio alginolyticus by droplet digital polymerase chain reaction PCR (ddPCR) in aquatic products. Methods The primer and probe of Vibrio alginolyticus in Method for the Detection of Pathogens in Food for Export—Real-time PCR Method (SN/T 1870-2016) were selected, and the ddPCR reaction system was established and optimized. The limit of detection(LOD) and the limit of quantitation (LQD) were tested based on ddPCR using pure bacterial genomic DNA and quantitative accuracy analysis was performed on the result. In order to verify the feasibility of the method, positive strain was added to pre-screening squid rings without background and the result obtained by ddPCR and quantitative real time polymerase chain reaction(qPCR)were compared. Results Vibrio alginolyticus performed good specificity in ddPCR detection in this experiment. In pure culture of Vibrio alginolyticus, the LOD and LOQ values overlapped each other, which was 2.2 copies/reaction, corresponding to 110 copies/ml. In the artificial contaminated experiment, the result of ddPCR for quantification of Vibrio alginolyticus were closer to theoretical value, and the repeatability and the detection rate of low concentration sample were also better than qPCR. The LOQ of artificially contaminated sample could reach 120 copies/g. Conclusion The result showed that quantitative detection of Vibrio alginolyticus by ddPCR had good specificity, high sensitivity and accuracy, which had practical application value.

Abstract:Objective To study the contamination and molecular characteristics of Campylobacter isolated from chicken carcasses in Shunyi, Beijing, and provide scientific basis for the prevention and control of Campylobacter infection. Methods Sixty samples of chicken carcasses were collected from wholesale markets and retail stores. The Campylobacter was isolated by filtration method. Multilocus sequence typing (MLST) analysis were performed for all of the Campylobacter isolates and the minimum spanning tree was constructed based on the STs. Results The positive detection rate of Campylobacter in chicken carcasses was 75.0% (45/60) and the constituent ratios of C.jejuni and C.coli were 38.0% (19/50) and 62.0% (31/50), respectively. The positive ratio of Campylobacter were 86.0% (37/43) and 47.1% (8/17) in wholesale market and retail store, respectively, and there was significant difference between the positive ratio (χ²＝9.877, P<0.05). The positive ratio of C.jejuni were 10.0% (2/20), 40.0% (8/20) and 45.0% (9/20) in May, June and July, respectively, and the positive ratio in May was significantly lower than both June and July (χ²＝6.624, P<0.05). Thirteen STs were identified from the 19 C.jejuni isolates and 16 STs were identified from the 28 C.coli. The antibiotic resistance ratio for C.jejuni was tetracycline (100.0%,19/19), nalidixic acid (100.0%,19/19), ciprofloxacin (94.7%,18/19), florfenicol (57.9%,11/19) and gentamicin (36.8,7/19). The antibiotic resistance ratio for C.coli was nalidixic acid (100.0%,31/31), ciprofloxacin (100.0%,31/31), tetracycline (93.5%, 29/31), streptomycin (93.5%, 29/31) and gentamicin (83.9%,26/31). The multi-antibiotic resistance ratio of C.jejuni and C.coli were 68.4%(13/19) and 93.5%(29/31), respectively. Conclusion Campylobacter contamination rate in carcasses of retail chickens in Shunyi was relatively high. C.coli was the dominant Campylobacter isolated in the chicken carcasses. Contamination rate of Campylobacter in chicken carcasses in wholesale markets was more serious than retail stores.

Abstract:Objective To investigate the serotype and biochemical analysis of Salmonella isolates from food contaminant monitoring, food poisoning cases and isolates of employees' physical examination in Haizhu District of Guangzhou City from 2012 to 2018. Methods 416 strains of Salmonella were isolated from 2012 to 2018, including 28 food poisoning strains, 5 food contaminant monitoring strains, and 383 health practitioner strains, which were biochemically identified and serotyped. Results There were 40 serotypes identified from 416 strains of Salmonella, including 56 S.Typhimurium strains (13.5%), 46 S.Enteritidis strains (11.1%), 41 S.Derby strains (9.9%), and 273 other serotypes (65.6%). Serotypes in group A-F were the most common in the region, and many rare serotypes were detected. Conclusion Community and serotypes of Salmonella in this region were numerous and widely distributed in the population. S.Typhimurium, S.Enteritidis and S.Derby were the dominant serotypes in the region. The screening of Salmonella serotypes was of great significance to the diseases caused by the bacteria.

Abstract:Objective To investigate the contamination and molecular typing characteristics of Cronobacter in infant food and formula powder in Wenzhou, to analyze the genetic relationship between different strains. Methods According to the national standard GB 4789.40-2010, Cronobacter was isolated and identified from food. Pulse field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to analysis the genotyping of Cronobacter. Results A total of 737 food samples were collected from 2013 to 2017, and the total detection rate of Cronobacter was 6.1% (45/737). The detection rate of infant formula rice flour was the highest, 23.4% (37/158). Totally 45 strains of Cronobacter were identified as C.sakazakii, C.malonaticus and C.muytjensii. Among them, C.sakazakii was the majority, accounting for 73.3%(33/45), followed by C.malonaticus of 24.4%(11/45). There were 25 ST types in 45 strains, and ST64, ST1, ST40, ST4 and ST7 were the dominant types. 45 strains of Cronobacter were divided into 38 clusters, and no obvious dominant cluster and aggregation were found. The result of PFGE and MLST showed that the majority of strains with the same PFGE type also had the same MLST type, but the same MLST type did not necessarily indicate a high genetic relationship. Conclusion The contamination level of Cronobacter was relatively low in foods of Wenzhou, among which the detection rate of infant formula rice flour was the highest. Cronobacter isolated from foods showed highly polymorphism and dispersion.

Abstract:Objective To understand the prevalence, serotypes, phylogenetic characterization, and antimicrobial resistance of Vibrio parahaemolyticus in shellfish products sold in Haikou City. Methods Five types of seafood(sea white, sea discharge, blood snail, razor clam and mango snail)collected from 2014 to 2016 were tested for Vibrio parahaemolyticus according to China national standard GB 4789.7-2013 and the National Food Contamination and Hazardous Factor Risk Monitoring Manual. All isolates were further identified and serotyped. Virulence genes were also detected by real-time fluorescent polymerase chain reaction(PCR). Drug resistance of Vibrio parahaemolyticus to a panel of antimicrobial agents were detected by K-B method. Results Vibrio parahaemolyticus was observed in 65 out of 157 samples covered the five kinds of shellfish. The detection rate of white shellfish was the highest(63.6%,21/33). Among the 65 of Vibrio parahaemolyticus positive samples, O3 and O5 were the main serotypes. 26 strains were completely typed and the overall typing rate was 40.0%. The dominant serotype was O1∶K25. Results of resistance analysis showed that 65 isolated strains were generally resistant to ampicillin (95.4%, 62/65). The intermediate resistance rate of cefotaxime was high(33.8%, 22/65).65 strains of Vibrio parahaemolyticus produced 5 kinds of resistance spectrum to 8 kinds of antibiotics. The result of Kanagawa experiment showed that 65 strains were not hemolytic. No thermostable direct hemolysin(TDH)and thermostable related hemolysin(TRH)genes were detected in all 65 strains of Vibrio parahaemolyticus. Conclusion The pollution of Vibrio parahaemolyticus in shellfish sold in Haikou City was serious. The monitoring of seawater quality in the culture area should be strengthened to prevent Vibrio parahaemolyticus infection.

Abstract:Objective To investigate the antibiotic sensitivity and molecular typing characteristics of enteropathogenic Escherichia coli (EPEC) isolates in out-patient diarrhea cases in Beijing. Methods 461 strains were tested for drug susceptibility. Random sampling principle was adopted for strains isolated at different time in and counties, and 140 strains were characterized by pulsed field gel electrophoresis (PFGE). Results The total drug resistance rate of 461 EPEC strains was 84.8%(391/461). Ampicillin, tetracycline, and methylbenzidine/sulfamethoxazole had higher drug tolerance rates of 66.4% (294/443), 54.0% (249/461) and 45.6% (210/461), respectively. 461 strains were divided into 200 resistance spectrums. 54.0% (249/461) of the isolates were resistant to 3 or more kinds of antibiotics, and 1 strain was resistant to 12 antibiotics. Common resistance spectrum was only resistant to nalidixic, accounting for 4.3%(20/461). Ciprofloxacin, nalidixic, tetracycline, imipenem resistance rates and types of drug resistance spectrum were slowly increasing year by year. 140 strains produced 136 PFGE patterns, and there was no dominant pattern. The similarity coefficient was 53.3% to 100.0%. Conclusion The resistance of EPEC isolated from diarrhea patients in Beijing was serious, the spectrum of resistance was complex, and the variety of multiple resistant strains and resistance spectrum increased yearly. PFGE patterns showed diversity.

Abstract:Objective To understand the situation of cadmium contamination in foods sold in Shenzhen, and then provide scientific basis for taking pertinent control measures. Methods Totally 2 410 food samples which included aquatic foods, vegetables and fungus, meat and its products, etc.were collected using stratified random sampling in 2017.The contents of cadmium were detected by inductively coupled plasma-mass spectrometry (ICP-MS) and evaluated by the Food Safety National Standards for Pollutant Limits(GB 2762-2017)and the Standards Limites of Cr, Cd, Hg, As and F in Tea (NY 659-2003). Results The detection rate of cadmium was 48.7%(1 174/2 410),and the over limit rate was 7.9%(190/2 410). Among these samples, aquatic foods were the most seriously polluted and the over limit rate reached 24.0%(187/780), and the cadmium content in shellfish was significantly higher than that in other aquatic foods, with the median content of 0.340 mg/kg and the over limit rate of 34.1%(184/540). The descending order of over limit rate was fruit(1.3%,1/80), vegetables and fungus(0.7%,2/270).The differences of the over limit rate from different sources were statistically significant(P＜0.05). Conclusion There were cadmium contamination in foods sold in Shenzhen and aquatic foods were the most seriously polluted, which may provide a reference for making polices and taking effective measures for supervision.

Abstract:Objective To study the design of foodborne disease early warning system and provide information technology support for government departments to prevent and control foodborne diseases. Methods Within the overall framework of population health information, the information of foodborne patients was collected based on the regional health information platform of prefecture-level cities. The geocoding technology was used to assign spatial location attributed to the monitoring data, and the spatial analysis method was used for visual display and statistical analysis. Results The design of the system broke through the bottleneck of the sentinel hospital, and extended the collection scope to all medical institutions and community health service centers in Zhongshan City, which could automatically obtain the main complaint cases that meet the definition of foodborne diseases, and grasp the foodborne diseases of the whole city from the individuals. The patient's visit and medication were summarized daily for all suspected foodborne illness cases on the day. Based on the spatial statistical analysis model, the service management personnel were notified to the suspected foodborne disease outbreak event on the same day. Conclusion The system design model based on regional health information platform can help solve the problem of hysteresis in foodborne disease early warning in China, and it will play a positive role in promoting public health informationization construction at local level and innovation in early warning and prevention mode.

Abstract:Objective To establish the contact surface area/volume ratio of different types of food contact material (FCM) in contact with liquors. Methods A total of 1 196 kinds of liquor consumed by Chinese population was collected in this study. Food contact area was calculated by direct measurement or 3D area measuring instrument. The contact surface area/volume ratio (S/V) was obtained by combining contact area with food packaging volume. Results 97.4%(1 165/1 196) of FCM in contact with liquor was made of single material, mainly glass and ceramics. The remaining 2.6%(31/1 196) was made of composite materials, mainly plastic and coated aluminum cans. The S/V of FCM in contact with liquor ranged from 2.84 to 19.67 dm²/kg. Further analysis found that 96.7%(1 156/1 196) of the S/V was greater than 6 dm²/kg, 81.9%(979/1 196) was ≥7.0-9.0 dm²/kg. Conclusion The majority of S/V in contact with liquor was higher than 6 dm²/kg, a parameter used by European Food Safety Authority(EFSA). Food contact S/V constructed by investigation can decrease uncertainty in food contact material risk assessment.

Abstract:Objective The article aimed to discuss the index of histamine for canned fish in relative food standards and regulations, and provide basic data for the revision of the index of histamine for canned fish in GB 7098-2015. Methods Descriptive analyses were conducted for the index of histamine for canned fish in relative food standards and regulations in China and abroad, as well as the histamine fish poisoning (scombrotoxin fish poisoning, SFP) in China. Statistical analyses were conducted for the histamine levels of fish with high histamine contents in canned fish in Guangdong Province, the adult consumers only consumption of canned fish and the reference value of histamine in Guangdong Province. Results China has a maximum level of 1 000 mg/kg for histamine in canned fish (only applies to canned Chub Mackerel, Carangidae and Sardines), which is higher than the histamine limits in the international standard or foreign standards. From 1998 to 2018, a total of 18 cases of SFP were reported in China, with the lowest histamine level of 120 mg/kg and the highest level of 3 820 mg/kg. 136 copies of canned fish samples were collected from the main production areas in Guangdong Province, and the histamine contents ranged from not detected(ND)to 488.8 mg/kg with 3.7% (5/136) exceeding 200 mg/kg and 1.5% (2/136) exceeding 400 mg/kg. Based on 120 g per consumption, which was the P97.5 consumption among canned fish adults consumers only in Guangdong Province and no observed adverse effect level (NOAEL,50 mg), the reference value of histamine in canned fish was 417 mg/kg. Conclusion The current national food safety standard GB 7098-2015 had a high histamine limit value for canned fish, moreover, only a few of fish species were required to determine the histamine levels. To revise the index of histamine in canned fish of the standard, it was suggested to conduct a risk assessment in canned fish with high histamine contents in China.

Abstract:Objective To isolate and identify the pathogenic bacteria in the first food poisoning related to bongkrekic acid in Guangdong Province. Methods The pathogenic bacteria was isolated and identified according to GB/T 4789.29-2003 Microbiological Examination of Food Hygiene, Examination of Pseudomonas cocovenenans subsp. farino fermentans. Meanwhile, 16S rDNA sequence of the isolates were analyzed. Results In 31 related food samples, 28 strains of Burkholderia spp. were isolated, including Burkholderia gladiolo(15), Burkholderia cepacia(3), Burkholderia vietnamiensis(3)etc. By 16S rDNA sequencing, in vitro toxin-producing test and bongkrekic acid measuring, 14 Burkholderia gladiolo isolates were identified as specific pathovar in 3 food samples. Conclusion It suggests that Burkholderia gladiolo could be identified by biochemical test and 16S rDNA sequence analysis. The Burkholderia gladiolo pathovar which could produce bongkreic acid was responsible for food poisoning, combined with toxin production.