Abstract:Objective In order to regulate the production of citrinin from the gene level and to provide a theoretical basis for improving the safety of Monascus used in food production, the quantitative analysis of citrinin in three strains of Monascus was performed, and the related gene clusters were studied. Methods The quantitative analysis of citrinin in three strains of Monascus during liquid fermentation was analyzed by high performance liquid chromatography (HPLC). The citrinin gene clusters were sequenced at Novogene Corporation (Beijing, China) and expression levels of genes involved in citrinin gene cluster were analyzed by real time polymerase chain reaction ( RT-PCR). Results There was no significant difference in the growth of Monascus purpureus YY-1, M2 and Monascus pilosus FJ-1 in both solid-state culture and liquid fermentation. In the liquid fermentation process, the yield of citrinin in M2 was the highest, followed by YY-1, and the production of citrinin in FJ-1 was the lowest. The similarity of the citrinin synthesis gene clusters in YY-1, M2 and FJ-1 reached 99.9%, exhibiting high conservation on gene level. The expression levels of six genes including membrane transport protein gene (orf5), polyketide synthetase gene (pksCT), oxidoreductase gene(ctnB), transcriptional regulation protein gene (ctnA) and dehydrogenase genes (orf1, ctnE) in the gene cluster were the highest in M2 and the lowest in FJ-1. Conclusion The citrinin yield was not related to the gene composition of citrinin synthesis gene cluster, but related to gene expression levels.

Abstract:Objective To understand the antimicrobial resistance of foodborne Salmonella isolates in China in 2016. Methods Broth microdilution method were used for the antimicrobial susceptibility of 775 Salmonella isolates against 16 antimicrobial compounds which belongs to 10 categories, and real-time fluorescence quantitative polymerase chain reaction method was used to detect the existence of mcr-1 gene. Results About 72.7% (549/775) isolates showed different antimicrobial resistant levels to 16 antimicrobials tested, and the resistance rates to nalidixic acid(NAL), tetracycline(TET), ampicillin(AMP)and ampicillin-sulbactam(SAM)were as high as above 34% while all strains were susceptible to imipenem (IPM) and meropenem (MEM). About 44.4% (335/775) were identified as multi-drug resistant (MDR) strains, among which resistance to as much as eight classes of antimicrobials was unfolded. There were 134 antimicrobial resistance spectrums with NAL, TET and AMP-SAM-NAL as the top three spectrums. Two isolates were identified carrying mcr-1 gene, one was Salmonella Derby serotype with resistance to 8 classes of drugs at the same time, while another one was Salmonella Typhimurium serotype with co-resistance to 7 kinds of drugs. Serious multi-drug resistance was found in some provinces. Conclusion An overall high level antimicrobial resistance was found among foodborne Salmonella isolates in 2016, so was the MDR condition, especially for strains recovered from some provinces. Mcr-1 gene could be carried in foodborne Salmonella isolates, therefore, close attention should be paid to its surveillance and further research on the antimicrobial resistance and transportation.

Abstract:Objective To investigate antimicrobial sensitivity of Staphylococcus aureus strains isolated from various food products in Yunnan Province during 2010-2016, in which, distributions of the multidrug-resistant (MDR) strains and the methicillin-resistant Staphylococcus aureus (MRSA) strains, and the carrier rates of mecA gene were determined for further epidemic control. Methods Antimicrobial sensitivity of the strains was detected by VITEK 2 Compact system with GPI and AST-GP67 cards. Polymerase chain reaction (PCR) with specific primers was used for detection of mecA gene. Results About 92.00%(299/325) of total 325 strains of Staphylococcus aureus were identified drug resistance, and the top three resistance were 88.00%(286/325) for benzylpenicillin, 43.38%(141/325) for tetracycline and 40.92%(133/325) for erythromycin. No strain showed resistant to quinupristin/dalfopristin, vancomycin, linezolid and tigecycline. The strains with MDR and MRSA were accounted for 47.69%(155/325) and 13.23%(43/325) respectively. Significant difference was observed in strains from different food products showing resistant to benzylpenicillin, tetracycline and nitrofurantoin(P< 0.05). The strain with 9 drug-resistant was detected in cooked food, fast-frozen food and meat or meat-products. The strains with MRSA were found in aquatic-products with positive rate of 33.33%(1/3), in meat or meat-products with positive rate of 17.89%(17/95), in baked food with positive rate of 16.67%(3/18), in milk or dairy products with positive rate of 14.29%(3/21), in cooked food with positive rate of 12.41%(17/137), in fast-frozen food with positive rate of 5.71%(2/35). No positive detection was found in infant food, frozen drinks and soy products(P>0.05). Significant difference was found in resistant rate to ciprofloxacin, moxifloxacin, trimethoprim/sulfamethoxazole during 2010-2016 (P<0.05). Some strains isolated in 2012-2015 were identified with 9 drug-resistant. Positive rate of MRSA during 2010 to 2016 was respectively 0.00%(0/15), 10.00%(2/20), 6.82%(3/44), 14.12%(12/85), 16.47%(14/85), 20.00%(12/60) and 0.00%(0/0). In strains with MRSA, 43 were resistant to benzylpenicillin(100.00%,43/43). However, no strain with MRSA was resistant to vanconycin. The carrier rate of mecA gene in all strains was 37.21%(16/43). Conclusion The tendency of antibiotics resistance evolved in Staphylococcus aureus in popular food should be concerned,which would be beneficial to prevent foodborne disease and guide the rational clinical practice for Staphylococcus aureus.

Abstract:Objective To determine the main serogroups, virulence genes and molecular typing of Listeria monocytogenes isolates in Wenzhou, and investigate clustering patterns and pathogenicity of the local strains. Methods Polymerase chain reaction(PCR) was applied to determine the serogroups and virulence genes of the isolates. Multilocus sequence typing (MLST) was used to identify molecular types of the strains. Results Ninety-seven strains were divided into four serogroups. The major serogroups were 1/2b(48.45%,47/97) and 1/2a(35.05%,34/97). The positive rate of pathogenicity gene iap and prfA were both 100.00%(97/97). All strains from patients carried five virulence genes,the overall hemolysin gene hlyA and inlA were 97.94%(95/97) and plcB was 96.91%(94/97). These ninety-seven stains were divided into twenty MLST types including the prevalent ST87, ST121 and ST9, patient-specific ST1 and ST779 as well as ST2, ST3 and ST5 that were found both in food and in patients. Conclusion This result demonstrated a high prevalence and genetic polymorphism of Listeria monocytogenes from diverse sources in Wenzhou. The majority of isolates carried pathogenicity-related genes, which posed a potential threat to the public health. The surveillance and management should be strengthened to prevent the infectious listeriosis.

Abstract:Objective To evaluate the relative risk of Vibrio parahaemolyticus(VP) in different categories of seafood for population in Dalian. Methods Four categories of 944 seafood samples were randomly collected from 10 districts in Dalian. The quantitative detection of VP in seafood was carried out by national food safety standard (GB 4789.7-2013). The virulence gene of VP was detected by the real-time fluorescent quantitative polymerase chain reaction(PCR). Seafood intake was obtained by food frequency method. Parameters of cross-contamination and cooking habit of seafood were obtained by expert consultation. Risk ranking of VP in 4 kinds of seafood was calculated by swift quantitative microbiological risk assessment (sQMRA). Results Crustacean had the highest per serving risk for pathogenic VP and the highest per annum cases among all the seafood categories, which was 3.5×10-6 and 2 799.3, respectively. Fish had the second highest per serving risk for pathogenic VP and the second highest per annum cases, which was 1.1×10-6 and 1 304.4, respectively. Cross-contamination was the main route that caused the incidence of VP. Conclusion Attention should be paid to the risk of VP caused by crustacean in the local area. Avoiding cross contamination was the key to reduce the risk of VP in seafood.

Abstract:Objective To explore the regularity and features of the poisonous animal and plant poisoning incidences and provide the bases to build up the prevention and control measures. Methods The database for poisonous animal and plant poisoning in Yunnan from 2012 to 2017 was set up, and the times, places and poisoning factors were analyzed. Results There were 530 incidents,4 147 cases and 64 deaths.The incident peak was from October to December, accounted for 30.8%(163/530),37.4%(1 553/4 147) and 50.0%(32/64) of the reported incidents, cases and deaths for the whole year. The largest number of poisonous plant poisoning incidents happened in the Chuxiong City, Dali City and Yuxi City, accounted for 44.2%(212/480). The largest number of poisonous animal poisoning incidents happened in the Diqing City, Nujiang City and Baoshan City, accounted for 80.0%(40/50). The largest number of incidents, cases and deaths happened in the family scenario,accounted for 63.6%(337/530),40.3%(1 672/4 147) and 89.1%(57/64) respectively.Poisonous animal poisoning was mainly caused by pupa 7.9%(42/530), poisonous plant poisoning was mainly caused by aconite 30.2%(160/530), kidney bean 29.2%(155/530),castor bean 5.3%(28/530), honey 3.8%(20/530) and oil tree 3.6%(19/530). Conclusion The situation of poisoning caused by poisonous animal and plant was serious in Yunnan Province.The efficient emergency response system of outbreaks had to be improved to decrease the mortality rate of the incidence. Food safety inspection and education should be strengthened.

Abstract:Objective Method were developed to detect three ochratoxins including ochratoxin A (OTA), ochratoxin B (OTB) and ochratoxin C (OTC) in wine via QuEChERS combined with high performance liquid chromatography (QuEChERS-HPLC) and HPLC-tandem mass spectrometry (HPLC-MS/MS). Methods The wine samples were diluted with acetonitrile-glacial acetic acid (90∶10, V/V) and then purified with a modified QuEChERS using a scavenging agent combination of C₁₈, SiO₂ and MgSO₄ after centrifugation. The separation was performed on C₁₈ column (4.6 mm×250 mm, 5 μm) after the gradient elution on a liquid chromatography. Three ochratoxins contaminants in wine were analyzed by HPLC-FLD and HPLC-MS/MS-ESI in the positive ionization under the multiple-reaction monitoring (MRM) mode. Results By these method, the limit of quantification (LOQ) were 2.0 μg/kg and the relative standard deviation (RSD) was between 2.01%-7.52% (n=6). Conclusion The developed methods were proved to be simple, sensitive, reproducible and were suitable for the determination of ochratoxins in wine in daily supervision.

Abstract:Objective A simple and rapid QuEChERS-high performance chromatography-tandem mass spectrometric method was developed for the determination of 4 pesticides, imidacloprid, indoxacarb, phoxim and carbofuran, in bamboo shoots. Methods The residues were extracted from the bamboo shoots with acetonitrile and cleaned up with N-propyl ethylenediamine (PSA), then detected by liquid chromatography-tandem mass spectrometry under multiple reaction monitroring mode (MRM), and quantified by matrix-match calibration curves. Results The recoveries in samples were between 72.4%-92.8% at three spiked levels from 4 to 40 μg/kg, with relative standard deviations of 1.5%-9.2%(n=3). The limits of detection (LOD) of four pesticides were 0.4 μg/kg, while limits of quantification (LOQ) were 1.2 μg/kg. The linear ranges were 0.5-20.0 ng/ml and the correlation coefficients (r²) were above 0.991. Conclusion The method of QuEChERS combined with high performance liquid chromatography-tandem mass spectrometry was accurate, sensitive, simple and convenient for the determination of the 4 pesticide residues, imidacloprid, indoxacarb, phoxim and carbofuran, in bamboo shoots.

Abstract:Objective To establish a method for the determination of 5 arsenic species including arsenite [As (Ⅲ)], arsenate[As (Ⅴ)], monmethyl arsenic (MMA), dimethyl arsenic(DMA) and arsenobetaine (AsB) in the soaking solution of healthy food teabag by high performance liquid chromatography-inductively coupled plasma mass spectrometry method (HPLC-ICP/MS). Methods The samples were extracted by hot extraction. Five arsenic species were separated in 10 min by Dionex IonPac AS19 (4 mm×250 mm, 10 μm) anion exchange column with 30 mmol/L ammonium carbonate (pH=9.5) as the mobile phase for isometric elution. Results The linear ranges for 5 arsenic species were between 0.2-300 μg/L with the linear coefficients more than 0.999, and the detection limits were between 0.04-0.08 μg/L. The repeatability of the method was examined by precision. The relative standard deviation (RSD) for the 5 arsenic species were less than 5% and the recoveries were between 80.3%-121.1%. Conclusion The method was suitable for the analysis and determination of arsenic species in the soaking solution of healthy food teabag. The experiment proved that the main arsenic species in healthy food teabag were As (Ⅲ) and As (Ⅴ). Attention should be paid to the risk of inorganic arsenic.

Abstract:Objective To accumulate data and experience for the prevention and control of mushroom poisoning through investigation and summary of one mushroom poisoning caused by a new species:Amanita subpallidorosea, which was collected from Wuchuan County, Zunyi City, Guizhou Province. Methods Epidemiological investigations were carried out soon after the mushroom poisoning incident occurred. Suspicious mushroom specimens were photographed, recorded and collected, species identification and acute toxicity test were taken subsequently. Results On September 19th, 2014, one father and his son from rural area of Wuchuan County developed symptoms of nausea, vomiting, abdominal pain, and diarrhea in 9 hours and 17 hours after eating some white wild mushrooms collected by themselves from the forest just behind their yard. The two patients developed acute liver failure and their main symptoms were as follows:the highest alanine aminotransferase of case 1 reached 1 279 U/L, and case 2 was 6 070 U/L; the aspartate transaminase of case 1 reached its peak at 2 829 U/L, and for case 2 was up to 6 868 U/L. Since the diseases were aggravated, several abnormal clinical indicators of patients appeared and the two patients died on the 5th and 7th day after poisoning due to multiple organ failures. Based on morphological and molecular studies, the suspicious mushroom was identified as a new lethal species, Amanita subpallidorosea. All the tested 5 male mice and 3 out of 5 female mice died in the acute oral toxicity test. Conclusion This food poisoning incident was caused by the lethal mushroom, Amanita subpallidorosea, which was mistakenly regarded as edible mushrooms.

Abstract:Objective To investigate a case caused by mushroom poisoning and identify the mushroom in Qianshan, Jiangxi Province. Methods The case was studied with the epidemiological investigation, clinical treatment data, and the suspicious mushroom samples were identified by morphology and molecular biology. Results The epidemiological investigation showed that all the patients ate mushrooms picked by themselves, the incubation period was about 4 hours, and the typical symptoms included gastroenteritis, vomiting and so on. After treatment with fluid support, corticosteroid, liver protection, all patients recovered after 3 days. The molecular biological evidence showed that the samples were probably Chlorophyllum molybdites. Conclusion The case was caused by Chlorophyllum molybdites poisonous mushroom. The poisonous mushroom species could be identified combined with epidemiology, morphology and molecular biology method.

Abstract:Objective To analyze the outbreaks of mycetism in Hunan Province from aspects including temporal-spatial distribution and risk factors, and to provide scientific basis for the control of mushroom poisoning. Methods Surveillance data was acquired on mushroom poisoning in 122 districts and counties in Hunan Province during 2014 and 2016. Software ArcGIS 10.2 was used to establishi geographic information database of cases and spatial regression was conducted. Results 4 081 cases of mycetism was reported in the 122 districts and counties in Hunan during 2014 and 2016, the average annual incidence was 2.01/100 000, the average case fatality rate was 0.61% (25/4 081), and most of the cases occurred during June and September. Spatial aggregation of cases was detected with Moran's I=0.327, P<0.01. Spatial regression showed that incidence of mushroom poisoning was in positive correlation with average annual temperature, number of health institutions per capita, number of secondary school students, and in negative correlation with number of faculty and staff in secondary schools. Conclusion Hunan was among the high mycetism prevalence areas in China. There was spatial aggregation of incidents. Incidence of mushroom poisoning was in positive correlation with average annual temperature, number of health institutions per capita, number of secondary school students, and in negative correlation with number of faculty and staff in secondary schools.

Abstract:Objective To investigate the prevalence of Norovirus in oysters cultured from farms, markets and restaurants, and to assess the foodborne disease risks. Methods Real-time reverse transcription polymerase chain reaction (RT-PCR) method was used to detect Norovirus RNA in oysters from farms, markets and restaurants. The semi-quantitative risk assessment for Norovirus in oysters was made by Risk Ranger. Results The overall detection rate of Norovirus in the 480 oyster samples was 11.04% (53/480). The detection rates of Norovirus in oyster samples from farms and markets were 15.83% (38/240) and 12.50% (15/120), respectively. No Norovirus was detected in oyster samples from restaurants. All Norovirus detected were genogroup Ⅱ(GⅡ). The relative risks for Norovirus caused by eating processed oysters and raw oysters were 44 and 67, the probabilities of illness caused by oyster per day per consumer of interest were 3.29×10-6 and 3.29×10-2, and the total predicted patients per annum of interest were 3.10×10³ and 3.10×10⁷, respectively. Conclusion The result highlight a high prevalence of Norovirus GⅡ contamination in oysters from farms and markets in Guangxi. Avoiding eating raw oysters and processing before eating are all effective method to decrease Norovirus infection.

Abstract:Objective To investigate microbial contamination of online ordering food in Yuexiu District of Guangzhou, and to provide reference for regulatory authorities. Methods Totally 120 online ordering food samples were collected during 2017 in Yuexiu District of Guangzhou. The microbial contamination of the samples, including the total plate count, Escherichia coli, methicillin-resistant Staphylococcus aureus, Salmonella,Bacillus cereus and Listeria monocytogenes were detected. Results The total unqualified rate was 39.17% (47/120), the unqualified rate and the levels of the total plate count and Escherichia coli were different among the 5 kinds of online ordering food(P<0.05). The transportation distance of qualified samples were shorter and the core temperature were higher(P<0.05). Spearman correlation analysis showed that transportation distance was positively correlated (P<0.05) with the total number of bacterial colonies and the core temperature had a negative correlation (P<0.05) with the level of hygiene indicator. Conclusion The sanitation situation of online ordering food in Yuexiu District of Guangzhou was worring, especially for hygiene indicator. It may cause food safety problems and was worthy of attention.

Abstract:Objective Analyze the serotype distribution and drug resistance of Shigella from patients in Henan Province in 2016. Methods Fifty Shigella strains which were isolated from 2 896 diarrhea patients by 15 sentinel hospitals in Henan Province were tested for serotype and drug susceptibility with broth dilution method, and etiological food information were collected and analyzed statistically. Results Shigella flexneri and Shigella soonei were dominant serotype, among which Shigella flexneri 2a subtype was the No.1 pathogens, accounted for 52.0%(26/50), followed by Shigella soonei II phase accounted for 26.0%(13/50). For drug susceptibility test for 10 kinds of antibiotics, the antibiotics with high resistance for Shigella included nalidixic acid (100.0%,50/50), tetracycline (100.0%,50/50), ampicillin (98.0%,49/50) and sulfonamide (90.0%,45/50). Conclusion The multidrug resistance was serious.

Abstract:Objective To assess the impact of Fukushima nuclear power plant accident on the level of radioactive level of the seafood in Nantong. Methods Samples of shellfish, fish, shrimps and crabs were collected quarterly (except fish moratorium), and total alpha and beta ray levels were tested. The pomfret and clams were sent to Jiangsu provincial disease prevention and control center for radionuclide detection in 2017. Results The total alpha and total beta ray levels of clams, golden hooked shrimps, pike crabs, and yellow fish were not correlated between each year (P>0.05), There was no regression relationship between years of total alpha radioactivity level (F(1,5)=0.126, P>0.05), while the total beta ray was the opposite (F(1,7)=4.65, P<0.05).The natural nuclides ²³⁸U, ²³²Th, ²²⁶Ra and ⁴⁰K in clams and pomfret were at background level, and the level of artificial nuclide of ¹³¹I, ¹³⁴Cs and ¹³⁷Cs were less than the detection limit. Conclusion Japan's Fukushima nuclear accident had not affected seawater products in the region for the time being. It was still necessary to continue monitoring the dynamic trends of the radioactivity level of marine products in the sea.

Abstract:Objective To understand the distribution characteristics of Vibrio parahaemolyticus (VP) in aquatic products and their environment samples in Huzhou, then to explore possible influencing factors of VP pullution in freshwater products. Methods One thousand three hundred and eighty-eight aquatic products and their environment samples were collected in Huzhou between 2014 to 2017. Aquatic products and environment samples were tested for VP, O group of serum and the virulence genes tlh, tdh and trh, respectively. To the distribution characteristics of VP in freshwater products, seafoods and environment samples was analyzed and compared. The possible influencing factors of VP pollution in freshwater products was further analyzed in Huzhou City. Results The rate of VP in aquatic products was 25.68%(265/1 032), of which freshwater products and seafood were 30.33% (175/577) and 19.78% (90/455) respectively, and the difference was statistically significant (χ²=14.83, P<0.001). The rates of VP in subsoil sediment and water body from sales links were 0.86% (1/116) and 13.71% (17/124) respectively. There is no VP detected in the water body from breeding links. By multivariate logistic regression analysis, the aquatic species, preservation method, sales links and time affected VP pollution of freshwater products to a certain extent. There was no significant difference in the distribution of virulence genotypes between aquatic products and environmental samples (P＞0.05), all of which were dominated by tlh+tdh-trh-. In the serotype distribution, there was no significant difference between freshwater products and seafood (P＞0.05), which O3 were mainly serotypes, followed by O4 serotypes. Conclusion Freshwater products was seriously polluted by VP in Huzhou, and pollution mainly comes from cross-contamination in the sales links. Monitoring and management should be further strengthened.

Abstract:Objective To understand the nitrite residual content of commercial cooked meat products in Gansu,and assess the health risks. Methods Through the meat consumption survey about of 1 466 residents by non-continuous 3 day 24 hour review method, combined with the detection data of nitrite content in 363 commercial cooked meat products, daily nitrite exposure was obtained by simple distribution method, compared with nitrite acceptable daily intake, and the nitrite exposure risk in Gansu residents was assessed. Results Nitrite detection rate of commercial cooked meat products was 85.40% (310/363) in Gansu Province, the violation rate was 3.31% (12/363), and the average content was 7.76 mg/kg. Daily nitrite exposure from meat was 0.002 3 mg/kg BW on average, and the high exposure was 0.008 3 mg/kg BW, account for 11.86% of the acceptable daily intake. Conclusion There was no safety concerns from meat nitrite for residents in Gansu Province, but the reasonable use of nitrite in cooked meat products should be improve.

Abstract:Laws, regulations and standards related to novel food management carried out by countries and regions such as China, the European Union, the United States, Canada, Australia and New Zealand were collected and summarized. The similarities and differences on definitions, scopes and categories of novel food were compared and analyzed. Definitions, scopes and categories of novel food defined by different countries and regions and the application of related documents which support the novel food management were studied. The definition of ‘traditional food’ or ‘history of food use’, and the categorization of novel food were compared and discussed in order to provide suggestions for the revision of novel food regulations and improvement of novel food management and standardization.

Abstract:Objective The purpose of this research was to isolate and identify the pathogenic bacterium which might cause the bacterial food poisoning accident in 2016 in Putian. The traceability analysis of the pathogenic bacterium was also emphatically investigated. Methods The bacteria in the collected samples were isolated, cultured, biochemical identified and serotyped. Pulsed field gel electrophoresis(PFGE)were used for the homology analysis of the isolated strains. Virulence gene detection and drug susceptibility analysis of the isolated strains were also applied. Results A total of 23 strains of Salmonella enteritidis were isolated, of which 8 strains were isolated from the retained food samples, 2 strains from the cooks and 13 strains from the patients. The result of cluster analysis using BioNumerics indicated that all of the strains were 100% homological. The virulence gene invA were detected in all these strains with the same drug-resistant spectrum. Conclusion This food poisoning accident was caused by Salmonella enteritidis which carried by the cooks to the food during the preparation of the cold cuts and the fresh fruit platter. PFGE were useful for the traceability analysis of bacterial caused food poisoning.