Abstract:Objective To elucidate the antibiotic-resistance(AR) distribution,AR level and the transfer of AR genes in non-pathogens isolated from ready-to-eat food in Xi’an,and evaluate the potential food safety risk.Methods The erythromycin and ampicillin resistance,the AR gene transfer,16S rRNA gene sequence analysis were performed on the bacteria from ready-to-eat food samples collected from supermarkets of Xi’an,including cooked meat,fruit slices and Chinese salads.Results 42.5% of the isolates were erythromycin resistant,47.5% were ampicillin resistant,while 21.2% were resistant to both antibiotics.11.3% of Ermr strains could grow under 160mg/L Ermthromycin,6.3% of Ampr strains could grow under 500mg/L ampicillin.After 1000 generations on medium without antibiotic,60% and 45% of randomly selected Ampr and Ermr strains lost their antibiotic resistance.Within these strains,the Ermr and Ampr fragments could be transferred from the antibiotic-resistant strains into the negative strains.Most antibiotic-resistant strains belonged to Enterococcus,Staphylococcus,Bacillus and Pseudomonas.Conclusion There was a potential food safety risk of non-pathogens in ready-to-eat food,and the transfer of AR genes might have some impact on the human intestinal flora and pathogenic bacteria.

Abstract:Objective To obtain an overview of distribution of enterotoxin genes and epidemic characteristics of S.aureus through gene testing and genotyping of isolates from food in Shanghai from 2006 to 2009.Methods Enterotoxin genes in 49 S.aureus strains from food were tested by PCR including five traditional enterotoxin genes(SEA-SEE) and four newly discovered genes(SEG-SEJ).Pulse-field gel electrophoresis(PFGE) was used for genotyping.Results The total detection rate of enterotoxin genes was 38.8%.And the traditional enterotoxin genes SEA and SEC were detected,93.8% of which belonged to SEC.The newly discovered enterotoxin genes including SEG,SEI,SEJ and SEH were also detected.The method of PFGE successfully classified 44 isolates into 28 gene types with 5 isolates indeterminable.Conclusion A wide varity of S.aureus genomic types could contaminate food and lead to food poisoning.The surveillance and ongoing monitoring of S.aureus should be strengthened to provide scientific basis for food poisoning prevention and control.

Abstract:Objective To analyze the characteristics of major allergen components from protein extracts of swimming crab Portunus trituberculatus in Tianjin region.Methods Crude protein extracts were prepared from the crab and separated by SDS-PAGE,then transferred to PVDF membrane and incubated with patients’ specific IgE(sIgE) serum mixture and individual patient’s sIgE serum,respectively.After incubated with the second antibody,the reactivity was detected among different patients.Results SDS-PAGE showed 9 protein bands in the extracts,of which 70 and 74kD were at high level.Western blot showed that patients’ sIgE serum mixture could react with the majority of proteins in the extracts except 21 and 38kD proteins.The allergens in different patients were heterogeneous.Conclusion Three major allergens(36,48 and 94kD protein) were identified in the extracts of swimming crab Portunus trituberculatus from Tianjin,but there was also individual difference.

Abstract:Objective To investigate the antibiotic resistance and molecular types of S.wandsworth strains isolated in Shanghai from 2009—2011.Methods K-B method recommended by WHO was used to detect 6 strains of S.wandsworth.Results were analyzed according to the breakpoints of CLSI 2010;Pulsed field gel-electrophoresis(PFGE) was used for molecular typing.Results One strain of S.wandsworth was resistant to trimethoprim and tetracycline.The others were sensitive to 10 kinds of antibiotics.Six strains of S.wandsworth were classified to 5 PFGE patterns and two of them were the same pattern.Conclusion S.wandsworth strains isolated from 2009 to 2011 were highly sensitive to antibiotics,and some showed higher homology.

Abstract:Objective To study and compare the prevalence of enterotoxin genes in foodborne Staphylococcus aureus isolates from food-poisoning and food inspection.Methods Isolates from food-poisoning and food inspection were tested by PCR method with five pairs of primers for sea,seb,sec,sed and see genes.Enterotoxin was analyzed in isolates from food-poisoning isolates with mini-VIDAS.Results 30 out of 110 samples were enterotoxin gene positive(27.3%,30/110) and only one type of enterotoxin gene existed in all positive samples.Both enterotoxin and relative gene of seb were found in 14 isolates from two food-poisoning events(100%,14/14).16 isolates from 96 food inspection samples were enterotoxin gene positive(16.7%,16/96),including 4 strains of sea,2 seb,4 sec and 6 sed.Conclusion Enterotoxin genes of sea,seb,sec and sed were found in Staphylococcus aureus isolates in Ningbo.Enterotoxin of seb is the major factor of food-poisoning caused by Staphylococcus aureus.

Abstract:Objective To develop a method of high performance liquid chromatography-linear ion trap mass spectrometry(HPLC-LIT-MS) for the determination of 23 industrial dyes in chili sauce and chili powder.Methods Samples were ultrasonically extracted with acetonitrile.The LC separation was performed on a RP-Amide column with gradient elution and the mass spectrometric acquisition was carried out under the mode of selected reaction monitoring(SRM).Results The average recoveries of 23 industrial dyes fortified in chili sauce and chili powder at 0.3,0.6 and 1.2 mg/kg were in the range of 73.9%-133.3% and 77.2%-128.4%,respectively.The limits of detection(LODs) were 0.5-56.0 μg/kg and the limits of quantification(LOQs) were 2.0-186.0 μg/kg.Conclusion The method is suitable for quantitative and qualitative detection of 23 industrial dyes in chili sauce and chili powder with advantages of fast,simple,precise and accurate.Rhodamine B,Chrysoidin and Sudan red Ⅳ were detected in 2 out of 73 chili products collected in local markets of Beijing.

Abstract:目的建立利用固相萃取-气相色谱法同时测定茶饮料中乐果、腐霉利、哒螨灵、高效氯氰菊酯4种农药的分析方法。方法考察了提取剂、固相萃取柱对检测的影响。样品采用乙腈提取,经弗罗里硅土柱净化,色谱柱采用Rtx-5(30 m×0.25 mm×0.25μm)。结果 4种农药的线性良好,相关系数为0.999 4～0.999 9,加标回收率为88.76%～102.4%,相对标准偏差小于5%,检测限在0.001～0.01mg/kg之间。结论该操作简单,节约了时间与有机溶剂,为饮料中多残留分析提供参考。

Abstract:目的优选QuEChERS方法中黄瓜拟除虫菊酯类农药残留净化剂的最佳组合。方法采用正交实验法,以农药加标回收率(气相色谱法)为指标,考察净化剂PSA(N-丙基乙二胺)、C18(C18烷基-硅胶)、GCB(石墨化炭黑)三因素的影响。结果重复试验表明,10 g黄瓜2 ml定容液净化剂的最佳组合是A2B1C2,即0.075 g PSA,0.025 g C18,0.050 g GCB。结论正交试验法用于优选蔬菜中农药残留检测的QuEChERS净化剂组合,既可节省试剂,又能满足检测需要。

Abstract:Objective To establish a new and reliable method for the accurate determination of selenium(Se) contents in foods by inductively coupled plasma mass spectrometry based on collided reaction cell technology with microwave digestion.Methods After microwave digestion,samples were directly determined by inductively coupled plasma mass spectrometry based on collided reaction cell technology.Internal standard element of zirconium(90Zr) was used to correct matrix interferences and signal drifting,high-performance Xs(X sensitive)interface was used to reduce non-mass spectrum interferences,and the collided reaction cell technology(CRCT mode) was used to eliminate mass spectrum interferences.Results The optimal linear range of the standard curve was 0-100 μg/L with a correlation coefficient of 0.999 8.The detection limit,the lowest quantitative limit,the relative standard deviation and the recovery rate were 0.002 5 mg/kg,0.007 5 mg/kg,1.6%-4.5% and 94.0%-104.0%,respectively.The results on three reference material,Wheat flour(GBW08503),Rice(GBW10010) and Wheat(GBW10011),were 0.059 mg/kg,0.073 mg/kg,0.048 mg/kg,met the scope of the standard value(0.049±0.014) mg/kg,(0.061±0.015) mg/kg and(0.053±0.007) mg/kg,respectively.The results were satisfactory.Conclusion The results showed that the method had many advantages such as sensitive,simple,rapid,accurate,good repeatability and recovery rate.It was consistent with arbitral method(HG-AFS),thus available for the accurate quantitative analysis of selenium in foods.

Abstract:Objective To develop a method for determination of acrylamide in French fries using solid phase extraction(SPE) and high performance liquid chromatography(HPLC).Methods The sample was extracted with aqueous solution of 2.0 mol/L sodium chloride,and cleaned up by a Styre Screen H2P SPE cartridge(200 mg/3 ml),then analyzed by a Sapphire C18 reverse phase column with methanol/water(5∶ 95,V/V) as mobile phase at the flow rate of 1.0 ml/min and the wavelength of 200 nm.Results The result showed that the average recoveries were between 66.2% and 80.9% in the range of 1.0-10.0 μg/g,and the relative standard deviations(RSDs) were between 1.6% and 2.1%,with a LOD(limit of detection) of 0.025 μg/g and LOQ(limit of quantification) of 0.080 μg/g.Conclusion This method was simple,fast,precise and could be used for rapid determination of acrylamiade in French fries.

Abstract:Objective To develop a high performance liquid chromatographic-diode array detector for the simultaneous determination of Lemon Yellow,Carmine,Sunset Yellow,Allura Red and Bright Blue in fermented flour products.Methods The separation was performed on a Kromasil C18 column(250 mm×4.6 mm,10 μm) with methanol/acetonitrile(1∶ 1,V/V) and ammonium acetate(0.01 mol/L,pH=4.0)as the mobile phase at the flow rate of 1.0 ml/min.The detection wavelength was 254 nm and the peaks of UV spectra were captured by a photodiode array detector(DAD).Results The method showed a good linearity in the range of 1.56-50.0 μg/ml(r=1.000 0).The average recoveries of colorants ranged from 98.9% to 101.6%,with RSDs of 0.11%-0.41%.Conclusion The method is simple,accurate,sensitive and reliable.

Abstract:Objective To provide references for successful traceability management on feed in China.Methods The overview of development for the feed traceability management was elaborated.The problems in traceability management of China’s current feed industry were analyzed,including relevant standards,regulatory system,recall system,costs,database construction and practitioners’ awareness.The solutions were preliminarily explored.Results The solutions for the above problems were proposed.Conclusion A full range "trinity" regulatory mechanisms for the successful traceability management on feed was developed.

Abstract:Objective To study acute diarrhea status and risk factors of dietary behavior in Shanghai.Methods A stratified multi-stage cluster random household sampling was used in this cross-sectional survey.Results The incidence rate of acute diarrhea among Shanghai residents was 0.68 episodes per person-year.It was 0.75 episodes per person-year for males and 0.62 episodes per person-year for females.It was estimated to be 0.96,0.54,0.71,0.71 and 0.64 episodes per person-year for age groups of 0-7,8-17,18-33,34-59 and ≥60,respectively.24.34% of respondents suspected their illness was due to contaminated food.40.03% of respondents had visited doctor.Single variable and logistic regression analysis showed that odds ratio of acute diarrhea were 1.37(95% confidence interval,1.13-1.67),0.66(95% confidence interval,0.49-0.88) and 0.76(95% confidence interval,0.62-0.94) for the respondents who had the behavior of eating delicatessen,keeping food at low temperature and salty taste.Conclusion Acute diarrhea is a common illness among residents in Shanghai.The incidence of acute diarrhea was slightly higher in males.After the age of eight,the incidence declined,but increased again in adult and then declined above 60.The behavior of eating delicatessen was a risk factor for acute diarrhea.The habit of keeping the food at low temperature and salty taste might be the protective factors for acute diarrhea.

Abstract:Objective Using ELISA method to test the content of lactoferrin in a number of brands of imported baby formula on the market and providing useful reference for dairy industries,inspection departments and consumers.Methods The in-house ELISA method is fast and simple,with high sensitivity,repeatability and practicability,could develop quality and quantity test at the same time.Results 16 kinds of imported baby formula were tested and the range of detectable lactoferrin content is between 16 to 167 mg/100 g.Conclusion As one of the nutrition enhancer of high-end baby formula,the content of lactoferrin has some differences between deferent brands.Relevant departments,dairy industries and customers should pay more attention to it.

Abstract:Objective To understand the epidemiological characteristics of food poisoning events in Guangxi and provide scientific basis for developing prevention and control strategies.Methods Descriptive epidemiological methods were used to analyze the characteristics of food poisoning events from 2005 to 2011 in Guangxi.Results 256 food poisoning events,6099 poisoning cases and 99 fatalities were reported during 2005—2011.Most events(75.39%) were caused by microorganism,toxic plants and animals.The second and third quarters were at the peak during a year when food poisoning events frequently occurred(61.33%).The numbers of reported food poisoning events were significantly different among regions in Guangxi,more from the western and northern and fewer from the eastern and southern.The rural households,schools and catering service units were the main places(78.13%).Conclusion The supervision and management of food safety for school canteens and social catering service units is one key to reduce the food poisoning events in Guangxi,and the other is propaganda and education of food safety in rural areas.

Abstract:Objective To obtain the data of market share and labeling status of genetically modified(GM) soybeans and their products in Shenzhen and provide scientific basis for government regulations.Methods In accordance with the monitoring plan,soybeans and their products were randomly collected from markets in Shenzhen on a periodic basis.Qualitative and quantitative detection of GM ingredients were carried out by real time polymerase chain reaction(PCR).The market share and labeling status of GM soybeans and their products were assessed,and the results were compared to those of 2006.Results 106 samples were monitored in 2011,and two samples were found to contain GM ingredients with the content of 0.93% and 0.51% respectively.The market share of GM soybeans and their products was 1.89%.There was no GM labeling on the packages of GM positive samples.Compared to the results of 2006,no significant differences were found in the market share and labeling status of GM soybean products.Conclusion Current market share of GM soybeans and their products in Shenzhen(except edible oil) was still very low,and there was no significant increase in the past five years.The management of GMO labeling still needs to be strengthened,and government should intensify law enforcement on this issue.

Abstract:Objective To investigate the residue of chloramphenicol in cooked meat products in Liaoning province and provide scientific data for regulatory authorities.Methods 162 samples were collected using stratified random sampling from 5 cities from Liaoning province.LC-MS-MS method was used according to the inspection standard with m-chloramphenicol as the internal standard.The detection rates were compared by χ2 analysis and P<0.05 was considered as statistical different.Results Chloramphenicol was detected in 40 out of 162 samples,and the detection rate was 24.7%.Detection rate was statistical difference among cites and food categories.Conclusion The situation of chloramphenicol residue in cooked meat products is serious and should arouse concerns of regulatory authorities.

Abstract:Based on the analysis of microbiological criteria for ready-to-eat foods in Codex Alimentarius Commission,the European Union,Australia,New Zealand,England and HongKong China,the article provides recommendations for the elaboration of microbiological criteria of Chinese national food standard.

Abstract:Principles,necessary materials and calculation processes of the exposure assessment methods in US,EU,Japan,Canada and China were introduced and those methods were compared on the aspects of their coverage,feasibility and difficulty,as well as their advantages and disadvantages.This study could provide scientific basis for establishing an exposure assessment method and food safety standards for food packaging materials,and provide references for the risk assessment and supervision authorities,related industries and enterprises.

Abstract:Objective To compare the similarities and differences on the management of chewing gum base and its ingredients in order to give advice on how to strengthen the management.Methods The regulations on chewing gum base of Codex Alimentarius Commission,European Union,USA,Japan,France,Spain,Italy,Australia and China were collected and compared.Results Most of these regulations regulate chewing gum base by setting up a permitted list of ingredients.The deficiency of some specifications of purity and safety in China was found.Conclusion We suggested that the regulation and food safety standards on chewing gum base and its ingredients should be perfected considering both the foreign paradigm and situation of China.

Abstract:Stigmatization,a typical group polarization phenomenon,is one of the most difficult situation risk communicator would encounter.We analyzed the stigmatization of food additives and discussed its characteristics and causes.We also gave out strategies for food safety risk communication practice.

Abstract:L-Hydroxyproline(Hyp) is a typical amino acid in hydrolyzed animal protein,which is a non-edible substance illegally added in food especially in milk and milk products.Therefore,Hyp could be used as an important indicator for food adulteration of animal protein hydrolysates.It is important for food safety and quality monitoring to develop a fast,efficient and sensitive method for hydroxyproline detection.This article reviewed the extraction,cleanup,derivation and determination methods of L-hydroxyproline in foods and biological samples.

Abstract:Many studies indicated that excessive intake of trans fatty acids will increase the risk of cardiovascular disease and other chronic diseases.This review mainly aims to analyze the management and food standards of trans fatty acids at domestic and abroad,and provide references for trans fatty acids management and risk assessment in China.

Abstract:This article gave an outline of the scientific knowledge on phthalates about their toxicity and regulations in USA,EU,Japan and China.The toxicity of PAEs varied with their molecular weight.The management of PAEs in above authorities was different.We also summarized the analytical methods for foods,food contact materials and biological samples in the recent five years.The results showed that different levels of PAEs could be found in food and biological samples.There are urgent needs for more validated analytical methods,enhancing exposure assessment and developing more rational regulations to protect the consumers.