Abstract:To investigate the effect of the flavonoids-rich fruit and vegetable juice intake on the oxidative damage related phase Ⅱ enzyme gene expression in rat liver.Methods54 healthy Wistar rats (SPF, male) were randomly divided into control group, lower dosage fruit and vegetable juice group and higher dosage fruit and vegetable juice group. The control group was treated with saline water and the latter two groups were treated with different dosage of fruit and vegetable juice for 5 weeks. Rat serums were obtained for the measurement of oxidative damage related biomarkers. Liver tissues were used for the detection of phase Ⅱ enzyme gene expression. The oxidative damage related phase Ⅱ enzyme gene mRNA expression was detected by RT-PCR and the serum T-AOC, MDA and GSH levels were tested by using experimental kits. ResultsComparing with the control group, fruit and vegetable juice increased the serum antioxidant capacity significantly, as well as up-regulated the mRNA expression of NQO1 and GCLC genes (P<0.05) in rat liver tissues. However, the dietary intervention had no effects on the mRNA expression of GSTP1, GCLM, GSTM2 and GSTA2 (P<0.05).ConclusionFlavonoids-rich fruit and vegetable dietary intervention improve the antioxidant capacity and the up-regulation of NQO1 and GCLC gene mRNA expression in rats.

Abstract:In order to study the toxicity of the culture supernatant of Clostridium sporogenes.MethodsStrains of C.sporogenes was isolated from the whey protein concentrate (WPC) and its products. The culture supernatant of C.sporogenes reached maximum in the early stationary phase of the bacterial growth in cooked meat medium or trypticase-peptone-glucose-yeast extract broth that contained rich glucose, ammonia and peptide. The culture supernatant of C.sporogenes and treated culture supernatant are injected to ICR mice intraperitoneally or by oral perfusion. The death of ICR was recorded. ResultsIntraperitoneal (i.p.) injection of the culture supernatant caused death of ICR mice. ICR mice showed slow the poisoning symptoms, including irritable, hair arched and shortness of breath and sudden death within 10 min, the average 5 to 7 min. The toxic effect of the culture supernatant produced by C.sporogenes is different from botulinum toxin poisoning.ConclusionWith the notable exception of production of botulinum neurotoxin, the isolation of C.sporogenes from WPC and its products suggest that the culture supernatant of C.sporogenes have the potential toxicity to be present in mice.

Abstract:To evaluate three extracting methods for mango proteins and analyze the protein components which could bind with serum specific IgE (sIgE) of allergy patients. To provide an optimal antigen extraction protocol for clinical detection of allergen specific IgE. MethodsProteins were extracted from mango using trichloroacetic acid precipitation method, trichloroacetic acid/acetone precipitation method and lysate extraction method, respectively. The total protein components were analyzed by SDS-PAGE and two-dimensional electrophoresis. Immunoblot technique and two-dimensional immunoblot technique were used to identify protein components which could combine with specific IgE. ResultsProtein components extracted by three methods were different. The single patient serum showed different affinity and binding sites in the immunoblot assay. Protein components from trichloroacetic acid precipitation method and trichloroacetic acid/acetone precipitation method reacted with patient serum mainly at 30,0, 44,7 and 90 kD, while that from lysate extraction method reacted with patient serum at mainly 23,2, 40,6, 73 and 90 kD.ConclusionThree kinds of extraction methods had different characteristics, and trichloroacetic acid precipitation method was more complete, reproducible, easy to operate and could meet the requirements of mango sIgE detection.

Abstract:To investigate the antimicrobial susceptibility and the pulse field gel electrophoresis (PFGE) patterns of 110 Escherichia coli O157 isolates from food in China,and to complete the characteristics of Escherichia coli O157 in food for the risk assessment.MethodsAntimicrobial susceptibility of all confirmed Escherichia coli O157 isolates was determined by agar dilution method. DNA collected fromall strains was digested by Xba I according to the standard PFGE protocolof US CDC. The PFGE patterns were analyzed with BioNumerics software.ResultsOut of all the isolates, 43 strains were resistant to at least one antibiotic.The top three antibiotics were tetracycline (30.0%, 33/110) , sulfamethoxazole (29.1%, 32/ 110) , nalidixic acid (26.4%, 29/ 110). In total, 24 antimicrobial resistance profiles were identified. 34 isolates were resistant to more than two antibiotics and 32 resistant to more than three antibiotics. The dominant multidrug resistant profiles were SMX (6) , AMP-NAL-SMX-SXT-TET (6) , AMP-CHL-NAL-SMX-SXT-TET(4) /AMP-SMX-SXT-TET (4) /TET (4). The antibiotic resistance rate of E.coli O157 was significantly higher than E.coli O157∶H7 (χ²=72.010 P<0.05). 37 E.coli O157∶H7 isolates haboring shiga toxin genes only were resistant to sulfamethoxazole (2.7%, 1/37), nalidixicacid (2.7%, 1/37) with no multi-drug resistant strains. Comparedby different food types, strains from raw pork and raw poultry had relatively higher resistance rates than other types of food. PFGE molecular typing completely separated E.coli O157∶hund and E.coli O157∶H7 strains.ConclusionThe antimicrobial resistance of Escherichia coli O157 isolated from food in Chinawas serious.The antimicrobial susceptibility surveillance should be strengthened, especially for E.coli O157 (including STEC E.coli O157) isolates to explore the relationship and transmission of antibiotic resistance strains between farming areas and retail sectors and to provide a scientific basis to develop antibiotic medication in farming.

Abstract:To analyze the antimicrobial resistance and molecular characteristics in foodborne Staphylococcus aureus in Beijing so as to prevent foodborne disease caused by Staphylococcus aureus and provide evidence for the reasonable clinical use of antibiotics.MethodsStaphylococcus aureus strains isolated from foodborne pathogenic bacteria monitoring network in Beijing from 2010 to 2012 were tested against 8 commonly used antibiotics using broth micro-dilution method. The isolates were further subtyped by PFGE. Results116 strains were antibiotic resistant, the resistant rate was 62.03%. The resistant rates for 8 commonly used antibiotics were erythromycin (45.45%), oxacillin (27.81%), clindamycin(20.86%),tetracycline(13.90%),chloramphenicol(11.76%), ciprofloxacin(6.42%), trimethoprim/sulfamet-hoxazole (5.88%). 52 strains were Methicillin-resistant Staphylococcus aureus (MRSA), and 135 strains were methicillin-sensitive Staphylococcus aureus (MSSA). 34 MRSA were multidrug resistant. Totally, 129 PFGE patterns were identified. No dominant PFGE patterns were obviously identified.ConclusionMultidrug resistant were popular among the Staphylococcus aureus strains isolated from food. PFGE patterns showed diversed characteristics. The antibiotic resistance spectrum and PFGE patterns showed no correlation.

Abstract:To investigate the contamination and the virulence genes of Staphylococcus aureus in the primary farm products of Minhang District, Shanghai.MethodsCHROMagar color medium and API S.aureus were used for separation and biochemical identification of S.aureus according to national standard. Virulence genes of coa,nuc,clfA,sea,seb, sec, sed and see were detected by real-time PCR methods．Results43 isolates were identified from 206 S. aureus samples,and the detection rate was 20.87%. All the identified strains had coa, nuc and clfA virulence genes, but no see virulence gene was found, and the remaining four virulence genes expressions were partially missing.ConclusionThe contamination of S.aureus in the primary farm products existed in Minhang district of Shanghai. Supervision and management should be strengthened for raw meat and poultry for serious contamination. All S.aureus strains contained coa virulence gene. It could be used as a target for detecting virulence genes.

Abstract:To investigate the nitrite content of Jiangshui purchased from markets in Gansu.MethodsImprovements had been made to the GB 5009.33-2010 method for determination of nitrite and nitrate in food, and the protein precipitation step was skipped. 62 samples, collected from April to August 2013, were detected using the modified method of GB 5009.33-2010. ResultsNitrite contents of 62 samples were lower than 2 mg/kg, and the average content was 0.64 mg/kg. Nitrite content of Jiangshui containing vegetables were higher than those not.ConclusionOn the basis of the national food safety standards for food contaminants (GB 2762-2012), the limit of nitrite in vegetables, their products and pickled vegetables was 20 mg/kg, and the 62 samples didn't exceed the standard.

Abstract:To establish an ultra high performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method for the simultaneous determination of 6-benzylaminopurine, gibberellins and 4-chlorophenoxyacetic acid residues in bean sprouts. MethodsThe samples were extracted with acetonitrile. The extract was cleaned up by a HLB solid phase column. The target compounds were separated by ACQUITY UPLC BEH C₁₈Column (100 mm×2.1 mm, 1.7 μm) with 0.1% formic acid and acetonitrile as the mobile phase, and then analyzed by ultra high performance liquid chromatography using positive and negative simultaneous scan mode and multiple reactions monitoring mode. ResultsThe linearity was satisfactory at concentrations ranging from 0.1 to 20 μg/L with linear correlation coefficient(r²)above 0.99.The limit of quantification (LOQ) was 0.5 μg/kg.The recoveries of the 3 analytes were in the range of 70.1% to 93.5%, and the relative standard deviations were in the range of 5.01% to 9.34%.ConclusionThis method was sensitive, fast and accurate. Therefore, it couldbe successfully used for the determination of 6-benzylaminopurine, gibberellins and 4-chlorophenoxyacetic acid residues in bean sprouts.

Abstract:A method was developed for the determination of 10 preservatives and bactericides in drinks by HPLC-DAD.MethodsThe samples were extracted by methanol and purified by solid phase extraction with a C8 SPE column. The analytes were separated on a C18 column, eluted by a gradient elution with 0.02 mol/L ammonium acetate buffer and methanol, detected by diode assay detector, and quantified by external standard method.ResultsThe calibration curve was linear within the concentration range of 0.1-10.0 μg/mL(r≥0.995 1). The lower limit of detection in drink was 0.25-1.0 μg/ml(S/N=10). The relative recoveries of 10 preservatives-bactericides in fruit juice drinks and carbonated drinks with 3 spiked levels were 74.1%-94.1%, and relative standard deviations(RSD)were 5.3%-15.1%.ConclusionThe method was simple, fast, low detection limit, meet for drinks foods at home and abroad in the above 10 kinds of antiseptic fungicide limited requirements, applicable to 10 kinds of preservatives and bactericides in drinks.

Abstract:To establish a method of high performance liquid chromatography (HPLC) for the determination (ADA) of azodicarbonamide in flour. MethodsSamples were extracted with acetone, then centrifuged and concentrated, the residue was dissolved with water. The injection was separated by cyano column and detected by photo-diode array. ResultsThe method showed a good linearity in the range of 2-40 μg/ml (r=0.999 8). The recoveries of ADA from flour spiked at three levels were in the range of 74%-118% with the relative standard deviations less than 5%. The limit of quantification (LOQ) was 3 mg/kg.ConclusionThis method could be used for screening and quantification of ADA in flour for its strong specificity and simple preparation.

Abstract:To determine 20 kinds of industrial dyes simultaneously in condiments with ultra high performance liquid chromatography(UPLC)．MethodsSamples were separated on a Endeavorsil C₁₈(100 mm × 2.1 mm, 1.8 μm)chromatographic column and gradient eluted of 20 mmol/L ammonium acetate aqueous solution(containing 0.1% formic acid) methyl alcohol. The wavelength of the detector was at 450,0 and 600 nm． ResultsThe calibration curve showed good linearity in the range of 2-40 μg/ml, and the correlation coefficients were better than 0.999. The limits of detection were in the range of 0.07-0.75 mg/kg. The recoveries of standard addition at three levels was 72.3%-93.0% and the RSD (n=6) was 1.0%-6.2%．ConclusionThe method was sensitive and accurate, it could be used for the detection of the 20 kinds of industrial dyes in condiments simultaneously．

Abstract:To develop a more sensitive immunologic method for SM₂ detection. MethodsAn indirect competitive chemiluminescence immunoassay was established with SM₂ monoclonal antibody, and was used to detect the SM₂ residue in animal derived foods. ResultsThe results indicated that the SM₂-mAb belongs to subclass of IgG_2b, and its affinity constant was 0.12×10⁷L/mol. The detection limit of SM₂-CLEIA was 0.174 μg/L with the linear range of 0.1 to 1 000 μg/L (r²=0.990 4), and IC₅₀ was 4.006 μg/L. The recoveries were from 94.41% to 104.40%. The variability within and between batches were 3.07% and 8.22%, respectively. There was no significant cross reaction between SM₂-mAb and SG or other drugs, and the results were 100% in accordance with those of the SM₂-ELISA kit.ConclusionSM₂-CLEIA was established, which was sensitive, specific, precise and with wide linear range.

Abstract:A high performance liquid chromatographic method was developed for determination of 8 fluoroquinolones residues in animal derived food (including marbofloxacin, ciprofloxacin, danofloxacin, norfloxacin, enrofloxacin, difloxacin, oxolinic acid, and flumequine).MethodsThe sample residues were extracted by EDTA-Mcllvaine buffer, purifid with PEP-2 solid-phase extrction column, seperated by ZORBAX C₁₈ (5 μm, 4.6 mm×250 mm) and quanlified by external standard calibration curves. ResultsMarbofloxacin, oxolinic acid, and flumequine in 30-360 μg/L, and the remaining five drugs in 15-180 μg/L linear relationship is good, the correlation coefficient is greater than 0.99. The detection limit (including norfloxacin, ciprofloxacin, enrofloxacin, difloxacin) is 2 μg/kg, the detection limit of danofloxacin is 0.5 μg/kg, the detection limit of marbofloxacin, oxolinic acid and flumequine is 8 μg/kg, the recoveries are between 77.6%-98.3%, the relative standard deviations are between 2.77%-9.35%.ConclusionThe method was simple, high accuracy and precision, less harmful to human body and could be satisfied with diffirent substrate test.

Abstract:A novel analytical method was developed for the determination of 31 β-agonists in pork by high performance liquid chromatography-Q-time of fight mass spectrometry.MethodsThe analytes were extracted from the samples using acetonitrile. After cleaning up with ODS-C₁₈, PSA and MgSO₄, samples were analyzed by HPLC-Q-TOF-MS using an electrospray interface in positive ionization mode. Gradient elution on a Poroshell C₁₈ column (2.1 mm×150 mm, 2.7 μm) allowed to resolve 31 target compounds and 9 internal standards in a total chromatographic run time of 27 min. ResultsThe regression coefficients (r) for the calibration curves (LOQ-100 μg/kg) were above 0.99. The LODs for 31 validated compounds were from 0.01-5 μg/kg. The recoveries were in the range of 39.0%-151.5% with RSD<15% (n=5).ConclusionThe results indicated that the method was simple, rapid, sensitive and suitable for the determination of β-agonists in pork.

Abstract:A rapid analytical method for the simultaneous detection of four metabolites of nitrofuran in eggs by the ultra pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established.MethodsThe metabolites in egg samples were released in HCl solution, and reacted with the 2-nitrobenzaldehyde (2-NBA). The stable derivatives were extracted by ethyl acetate, and centrifuged at. The transparent liquid was detected. The identification was achieved by electro spray ionization in positive mode using multiple reaction monitoring. The quantification was performed by the matrix matched internal standards. ResultsThe calibration curves of the four analytes showed a good linearity between 0.1 and 50 μg/L, and the correlation coefficient was above 0.995. Recoveries were between 74.1% and 97.6% with RSD less than 13.4%. The limits of detection of SEM and AHD were 0.1 μg/kg, and the limits of detection of AMOZ and AOZ were 0.05 μg/kg.ConclusionThe method has the advantages of simple pretreatment, high sensitivity and good reproducibility, which is suitable for the determination of four nitrofuran metabolites in eggs.

Abstract:To establish a method for the determination of azodicarbonamide (ADA) in wheat flour by HPLC.MethodsThe samples were extracted by acetone-dimethyl sulfoxide mixture with ultrasonic oscillations. The ADA separation was carried out on a Hypersil-C₁₈ column (250 mm×4.6 mm, 5 μm) with 10 mmol/L H₂SO₄ solution as mobile phase at a flow rate of 1 ml/min, and detected at 275 nm with a 20 μl injection volume. ResultsThe linear range for ADA was 0.01-1.00 mg/ml, and the correlation coefficient was 0.999 2. The average recovery was 95.9% (RSD<4.3%). The ADA content of 45 samples from Shandong province were lower than the detection limit, which were in line with the current standards.ConclusionThe method was proved to be simple and accurate with good repeatability and high sensitivity, which could apply to the determination of ADA in bulk wheat flour.

Abstract:To develop a genotyping and tracing method for foodborne pathogenic Staphylococcus aureus (S.aureus).MethodsFoodborne S. aureus isolates were identified through PCR method targeting coagulase gene and subtyped by RiboPrinter. Results62 isolates were identified as S.aureus and classified into six subtypes, and each subtype was hypodispersion.ConclusionCooperative use of PCR method and RiboPrinter method could precisely identify and classify S.aureus contamination, analyze the distribution and characteristic, and trace the possible fingerprint. This research may provide experimental data for pathogenic bacteria typing, and give technical support for food supervision and administration.

Abstract:Limits standards of rare earth elements in Chinese teas has been one of the hot topics in regards of tea safety in recent years. This paper reviews the current concerns of the elemental residues in Chinese teas, investigates the reasons for exceeding the standards, discusses the limits, and provides constructive suggestions for scientifically setting up limit standards of the rare earth elements in teas. It will help to strengthen the surveillance and management of tea quality.

Abstract:To monitor the sulfur dioxide residue in star anise in Guangxi, and understand the changes of the residues by cooking.MethodsA total of 180 star anise samples were randomly collected from supermarkets, whole sale markets (including individual retail point) in Guangxi. The sulfur dioxide residues were detected according to the NY/T 1435-2007 and evaluated by GB/T 7652-2006.The changes of sulfur dioxide residue by storage time and cooking were detected. ResultsThe detection rate of sulfur dioxide residue was 42.5% in 134 samples, and the violation rate was 36.6%. The sulfur dioxide residues were in the range of 1.5-660.6 mg/kg and the median was 106.6 mg/kg. The violation rates were 27.1% and 41.9% from supermarkets and whole sale markets respectively. Sulfur dioxide residue in star anise reduced from 660 to 19.2 mg/kg after cooking.ConclusionStar anise was fumigated by sulfur in Guangxi, which indicated that the relevant departments should strengthen supervision and monitoring. The results showed that the sulfur dioxide residue in soap and star anise was greatly decreased after cooking.

Abstract:To detect the pathogens of food poisoning samples and analyze the homology, help to trace the sources of contamination and clarify etiology diagnosis, and provide the basis for the prevention and control of food poisoning.MethodsThe pathogens were screened by fluorescence quantitative PCR , isolated according to the GB method, identified by ATB method, and the homology was analyzed by PFGE.Results8 strains of Salmonella enteritis were separated from 21 patients or operators, 2 strains were from 9 food samples. The detection rate were 25.00% and 6.25% respectively. Salmonella was not detected from water samples from canteen and well. Positive rates were the same for real-time fluorescent quantitative PCR and GB method. PFGE patterns of the 10 Salmonella enteritis were the same for cluster analysis.ConclusionThe food poisoning case was caused by the same clone of Salmonella enteritis. Real-time fluorescent quantitative PCR was helpful for rapid examination for pathogenic bacteria. GB method was important for the separation of Salmonella enteritis, and the above 2 methods could increase the detection rate and shorten the time spent. PFGE method could analyze the homology of the pathogenic bacteria, trace the source and was helpful to prevent and control food poisoning.

Abstract:The study was conducted to investigate the quality of paper-made food packaging materials in China．MethodsSamples were collected randomly from the industry all around the country. Solvent residue, evaporation residue and heavy metals were analyzed by the national standard method. Results99 samples from different corporations were tested. Detection rate of solvent residue was higher, and there was a higher quality safety risk. Benzene residue and PAHs residue from paper-made food packaging containers were more serious. Detection rate of PAHs residue reached 99%, detection rate of benzene residue among benzene series residue reached 100%, and toluene residue reached 76%.ConclusionWe should strengthen the supervision for paper-made food packaging material to ensure the safety.

Abstract:To investigate the contamination of Staphylococcus Aureus (SA) in ready-to-eat (RTE) meat products in Guangdong Province and make a preliminary risk evaluation, which would provide scientific basis for the prevention．Methods729 RTE meat products were collected from 21 cities and Shunde district of Guangdong province by random sampling and SA testing was carried out according to the national standard. A sQMRA tool was used to make preliminary risk evaluation for SA in RTE meat products.ResultsThe prevalence of SA in RTE meat products was 3.3%, the SA concentrations were from 1 to 340 cuf/g, and the average SA concentration was 10 cuf/g. The highest prevalence of SA was found in smoked barbecue RTE meat products. The peak seasons of SA contamination were the first and the fourth season．It was estimated that about 24,2 people were infected by SA during 2013. The estimated probability of SA infection was 2.3×10-4.ConclusionThe surveillance data showed that SA were existed at different levels in RTE meat products in Guangdong Province．Preliminary risk evaluation showed the SA risk of RTE meat products was relatively high. The health inspection on RTE meat products should be strengthened．

Abstract:Study the contamination of Staphylococcus aurous and Salmonella in raw frozen food products made of flour or rice in Henan 2012. MethodsStaphylococcus aurous and Salmonella were detected and the serotyping of Salmonella was performed by The Manual for National Food Safety Risk Monitoring (2012). The enterotoxin of Staphylococcus aurous was detected by the instruction of mini-VIDAS Staphylocouls enterotoxin Ⅱ. Results55 strains of foodborne pathogens were detected from 344 samples, and the detection rate was 15.99%. The detected strains included 49 strains of Staphylococcus aurous and 6 strains of Salmonella, accounting for 14.24% and 1.74% of the detection rate. Colony-forming units of Staphylococcus aurous for the positive samples were 0.2-110 cfu/g. 22 strains out of 49 strains of Staphylococcus aurous were enterotoxin-positive. The 6 strains of Salmonella were 4 serotypes, S.enteritidis, S.agona, S.Indiana and S.derby.All the strains of Salmonella were resistant to cefazolin, cefotetan, amikacin, gentamicin and tobramycin. 3 strains of Salmonella were resistant to ampicillin. 2 strains were resistant to ampicillin/sulbactam, ceftriaxone, aztreonam, nitrofurantoin and trimethoprim/sulfamethoxazole. 1 strain was resistant to ciprofloxacin and levofloxacin. ConclusionThere was contamination of Staphylococcus aurous and Salmonella in raw frozen food products made of flour or rice in Henan 2012. The rate of Salmonella contamination was lower, but the risk was higher, while it was the opposite for Staphylococcus aurous. The Staphylococcus aurous contamination should be also taken into account because of the higher enterotoxin-positive rate.

Abstract:Identify pathogens which causing food poisoning, analysis of genetic relationships among strains and provide the basis for the diagnosis of food poisoning clear.MethodsUsing quantitative PCR rapid screening, GB 4789.4-2010 method to separate and identify the pathogens. ResultsFrom the 16 cake samples detected 8 Salmonella enteritidis, 32 stool samples of patients detected 17 Salmonella enteritidis, PCR nucleic acid positive and the GB 4789.4-2010 method were isolated with the same strains. PFGE banding showed that patients had the same pattern of Salmonella enteritidis with which were detected in cake, and they had high homology.ConclusionThis food poisoning from Salmonella enteritidis contamination by the cake. PCR method with the GB 4789.4-2010 method helps to quickly lock joint detection of food poisoning bacteria. PFGE detected Salmonella enteritidis of the cake and patients were sourced from the same clone. It demonstrate the relevance of food pathogens from genes level.

Abstract:This paper reviews the developments of the management requirements, analytical techniques, and migration of the photoinitiators in various food matrices. The trends of the research on photoinitiators are also summarized and prospected.

Abstract:Di-(2-ethylhexyl)-phthalate (DEHP) is a widely used phthalic acid esters plasticizer, which might migrate to environment through plastic products or directly migrate from packaging materials to food, polluting the air, water, soil and food. DEHP can induce reproductive and developmental toxicity, immunotoxicity, embryotoxicity, hepatotoxicity, neurotoxicity and carcinogenicity. At the same time, it can also impose a certain influence on the endocrine system. The endocrine-disrupting property and neurotoxicity of DEHP and the interaction between them was reviewed in this paper.