Abstract:To understand the effects of different caprylic acid-ammonium sulfate concentration and centrifugal force on purification of HRP-labeled monoclonal antibody against tetrodotoxin (TTX) and to optimize the purification protocol for the antibody in order to provide the technical basis for TTX detection by immunoassay. Methods Under different centrifugal force and concentration of caprylic acid-ammonium sulfate, the antibody was purified and linked with the horseradish peroxidase enzyme (HRP), and the biochemical properties and parameters of HRP-labeled antibody were determined with indirect enzyme-linked immuno sorbent assay. Results The purity of antibody and HRP-labeled antibody obtained by different methods were different as well as other parameters and bioactivities. The best experiment conditions for high productivity and bioactivity of the monoclonal antibody were ascites diluent:lipoic acid (1000∶V/V) and 10000r/min centrifugation.Conclusion The purification protocol was optimized for the dilution and centrifugal conditions based on the productivity, purity and bioactivity.

Abstract:To investigate the distribution of virulence associate factors and antibiotic susceptibility of foodborne Bacillus cereus in China. Methods Ten virulence genes were screened by PCR technology, antibiotic susceptibility was determined in Broth Microdilution Susceptibility Testing. Results Hemolysin BL, enterotoxin T and cytotoxin K genes were the common genes. 87.4% of the strains carryed at least one virulence gene. Bacillus cereus was sensitive to gentamicin, vancomycin, ciprofloxacin, trimethoprim-sulfamethoxazole, erythromycin, tetracycline, chloramphenicol and clindamycin while resistant to ampicillin and cefotaxime. Conclusion Foodborne Bacillus cereus in China has strong pathogenicity, posing a potential food safety and public health threat. Ampicillin and cefotaxime had lower sensitivity which should not be used for empirical treatment and prevention.

Abstract:To establish a method to detect Listeria monocytogenes(LMO) by PCR-pyrosequencing.MethodsA pair of PCR primers and a sequencing primer were designed according to the hly gene of LMO. The target gene was amplified by PCR specifically and single-stranded DNA templates for pyrosequencing were prepared from the PCR products. Finally, pyrosequencing was performed under the guidance of the sequencing primer. The strains were identified by aligning the sequencing results to the hly gene sequence in GenBank.Results PCR primers and sequencing primers showed good specificity. The results showed that a 249bp DNA fragment was amplified from 16LMO strains and the pyrosequencing results perfectly matched the hly gene sequence, while the control strains were both negative.ConclusionThis new established method is accurate and effective for rapid detection of LMO.

Abstract:To establish a new method for geneotyping of Vibrio vulnificus.Methods PCR-denaturing gradient gel electrophoresis(PCR-DGGE)was used to elucidate the molecular characteristics of the polymorphism of 16S-23S rDNA intergenic spacer regions(ISR)from 18Vibrio vulnificus strains. Meanwhile, detection of virulence factors and antimicrobial susceptibility test of isolates were conducted to verify the relationship of the strains.Results The Vibrio vulnificus strains could be amplified into 4different bands by ISR-PCR, including 900,0, 650and 550bp. At the same time, Vibrio vulnificus ISR-DGGE sequences showed significant differences between the strains, and all 18strains were typed into 16types by DGGE. Clustering analysis divided them into two categories with similarity of 0.65and 0.71. The results of antimicrobial susceptibility test implied that drug resistant types of sj6, sj11and sj12were different from the other 15strains, which was consistant to the ISR-DGGE.ConclusionThis molecular technique could be applied to investigation and identification of Vibrio vulnificus, and provide a new method for geneotyping.

Abstract:To predict the allergenic potential of recombinant human α-lactalbumin (rhLA) expressed in the milk of transgenic cloned cattle using bioinformatics analysis.Methods The Allergen Online Database, Allergen Database for Food Safety and Structural Database of Allergenic Proteins were used to determine the similarity of amino acid sequences and structures between the expressed protein and known allergens. Results There was a high level of similarity between rhLA and some known allergens, including bevine alpha lactalbumin, bovine lactose synthas B proteina (Bos d 4) and chicken lysozyme C (1,4-beta-N-acetylmuramidase C, Gal d 4, Gal d IV).ConclusionRhLA has possible allergenic potential.

Abstract:To establish an oral Brown Norway(BN)rat model for food allergy. Methods Different doses(0.1,1.0, and 10.0mg/d)of ovalbumin(OVA)were administered to male and female BN rats with different age (4and 8weeks) by gavage for 35days. Specific serum IgE against OVA on the 28^th and 35^th days was analysed by enzyme-linked immunosorbent assay(ELISA). Results Daily gavage of 1.0mg OVA to 4-week female and 8-week female BN rats resulted in significantly higher concentrations of OVA sIgE on day 28and 35compared to the control group(P＜0.05). On day 28, the concentration of OVA sIgE was significantly higher in 8-week male BN rats exposed to 0.1mg OVA/day than the control group(P＜0.05). The concentration of OVA sIgE had no significant difference among all groups of 4-week male BN rats on day 28and 35. Conclusion Different doses of OVA were administered orally to BN rats with different sex and age. Females were more sensitive than males; age did not significantly influence the concentration of OVA sIgE; the better dose was 1.0mg. Therefore, an ideal animal model of food allergenicity can be established by 1.0mg/d OVA gavage to female BN rats for 28～35days.

Abstract:To compare four methods for developing immune-suppressed mouse models induced by cyclophos-phamide (CP) with different doses and ways,and choose the appropriate animal model of immunosuppression to evaluate the immunotoxicity of a substance. Methods The female BALB/c mice were assigned to five groups:the control group with distilled water daily gavage; CP gavage group with 40mg/kg BW/d by gavage; CP ip-1group with 40mg/kg BW/d by intraperitoneally injection (ip); CP ip-2group with 80mg/kg BW/d in the first three days by ip and once a week in the following period; CP ip-3group with 200mg/kg BW 24h before the end point by ip. The study lasted for 30days. ResultsThe immune organ weights,the number of leucocyte and the percentage of lymphocytes in peripheral blood,IgA and IgG levels in serum, the percentage of B cells in peripheral blood, the plaque forming cells in spleen, 24h footpad thickness change, LPS- and ConA-induced splenocyte proliferation in four cyclophosphamide groups were significantly lower than those in control group (P＜0.05). The percentages of neutrophils in peripheral blood in four cyclophosphamide groups were significantly higher than those in control group (P＜0.05). However, the percentage of NK cells in peripheral blood in CP gavage group and CP ip-1group were significantly higher than that in control group, and the percentage of Th cells and the ratio of CD4⁺ to CD8⁺ in CP ip-2group and CP ip-3group were higher than those in control group (P＜0.05). In addition, the body weight and liver relative weight in CP gavage group and CP ip-1group were lower than those in control group, the levels of alanine aminotransferase, glucose and triglyceride changed significantly (P＜0.05). There was no significant difference between CP ip-2group and CP ip-3group except the body weight and haematology parameters such as mean corpuscular hemoglobin concentration and red blood cell distribution width (P＞0.05). Conclusion The four ways of CP administration could induce immunosuppression in BALB/c mice, however the appropriate animal model of immunosuppression may be established by intraperitoneal injection of 200mg/kg BW CP 24h before the end point.

Abstract:To study the effect and mechanism of propolis flavonoids and its effective component on the regulation of lipid metabolism. MethodsThe effect of propolis flavonoids on serum lipids (TG, TC and HDL-C) and the key enzyme in lipid metabolism (HL and 7CYP7A1)were tested in hyperlipidemia rat model and primary cell line (hepatocyte and adipocyte) respectively; and the effect of the active component from propolis flavonoids on insulin resistance was observed in vitro as well. Results The levels of TG and TC in propolis flavonoids group were significantly decreased compared with the group of hyperlipidemia model (P<0.05). The levels of HL and 7CYP7A1were significantly increased compared with the group of hyperlipidemia model (P<0.05) in vitro. The effective component of propolis flavonoids, including 7-methylchrysin, quercetin-3-O-neohesperidin and caffeic acid, increased the glucose consumption in L6myotubes (P<0.05). Moreover, 7-methylchrysin in the dose of 0.4μg/ml and quercetin-3-O-neohesperidin in the dose of 10μg/ml could significantly reduce free fatty acids absorption in L6myotubes. Conclusion The mechanism of propolis flavonoids on the regulation of lipid disorders might be depend on the regulation of the key enzyme in lipid metabolism and the insulin resistance.

Abstract:Objective Effects of four chemical preservatives,acetic acid,citric acid, sodium chloride and sodium nitrite on the viability of Clonorchis sinensis metacercariae in vitro were studied. Methods Freshwater fish meat infected by Clonorchis sinensis metacercariae was digested and metacercariae were isolated from hydrolysis extract. Metacercariae were quantitively imbibed into PBS buffer containing different concentrations of food preservation chemicals. The viability and morphological structure of metacercariae in different chemicals were studied. Results The results showed that there was no significant effect from citric acid,sodium chloride or sodium nitrite on the viability of encysted metacercariae. 5% of acetic acid and 10% of alcohol solution could affect the movement of encysted metacercariae and eventually cause their death while it costed a long time treatment. Low concentration of alcohol could stimulate metacercariae and larvae activity, but vitality reduced with prolonged treatment. ConclusionOther non-heated treatment methods and their effects were still worth further study. \=

Abstract:To discuss the comprehensive assessment methods for evaluation of proficiency test results. Methods Statistical methods of Z-score, point-score-system and combination scores were used to evaluate the laboratory test results from three times and provide a general assessment. Results The pass rates that analyzed by Z-score method for the five targets were 78.1%, 93.8%, 81.2%, 90.6% and 93.8%, respectively. Using point-score-system, the pass rates of the three tests were 75%, 71.9% and 90.6%. And with combination scores, 81.2% of the laboratories showed satisfying performances. Conclusion The three evaluation methods showed advantages in different aspects and fit for the comprehensive evaluation of proficiency tests．Z-score fit for single tested substance; point-score-system was suitable for each test with multi-target substances; combination scores were competent for comprehensive assessment of each laboratory during several tests.

Abstract:To establish methods for the detection of inorganic arsenic in rice and rice-based foodstuff and compare the results deviation of various extracting and/or instrumental process. MethodsThe extraction conditions for inorganic arsenic extraction in rice were 0.15mol /L nitric acid or 0.3mol/L TFA; heat-assistant extraction 2h,95℃; ultrasonic 2h,75℃; microwave-assist 1h ,90℃. Then the extracts were separated by an anion exchange column Hamilton PRP X-100(250mm×4.1mm, 10μm) and detected by ICP-MS and HG-AFS respectively. Results The determination of inorganic arsenic of these two methods was good. The recoveries of spiked samples were 94.8%～111.7% and 91.9%～96.0%, and the relative standard deviations (RSD,n=6) were below 5.8%. The results were satisfying for control sample (SRM1568a) and rice samples. Conclusion The methods were simple, accurate and fast for the determination of inorganic arsenic in rice and rice-based foodstuff. There was no significant statistic difference among the results.

Abstract:To develop a new method for quantitative determination of 65herbicides belonging to different chemical families in vegetables by gas chromatography-mass spectrometry(GC-MS)．MethodsSamples were ultrasonically extracted with acetonitrile and the extracts were cleanuped with Carb/NH₂ cartridge before GC-MS analysis．Matrix-matched calibration was used for quantification．ResultsThe linearity was satisfying within the range of 10～1000μg/L,and the coefficients of determination(r)were above 0.998．The limits of detection(LODs)and the limits of quantification(LOQs)were 0.02～2.2μg/kg and 0.1～7.4μg/kg, respectively. The recoveries for spiked samples at the levels of 5,10and 20μg/kg ranged from 60.9% to 117.9%, except for EPTC and Etobenzanid in the range of 41.1%～59.4%．The relative standard deviations(RSD)were below 14.0%． Trifluralin was detected in 1out of 9vegetable samples collected from local market,with the concentration of 2.0μg/kg．Conclusion The proposed method was rapid,simple and sensitive for the analysis of 65herbicides in vegetables．

Abstract:To validate the mercury analyzer direct solid sampling method for determination of total mercury in health food.MethodsMercury analyzer direct solid sampling and atomic fluorescence spectrometry were used for determination of total mercury in health food.Results The results were consistent between the two methods in health food spiked with different concentrations of mercury. The recovery was 88%～116% with RSD＜10%.Conclusion Determination total mercury by mercury analyzer direct solid sampling method in health food was accurate, fast, low cost and without pollution. The method was comparable to the national standard method and could be applied nationwide.

Abstract:A method was developed for the simultaneous determination of 13quinolone (QNs) antibiobtics in Swine muscle by ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS).Methods The analytes were extracted from the sample using phosphate solution with ultrasonic bath and purified by anion exchange solid-phase extraction(SPE)cartridge. The residue was dried under nitrogen and redissolved for UPLC-MS/MS. The interference of matrix was reduced by the matrix-matched calibration standards curve. Results The linearity arrange was from 5μg/kg to 100μg/kg for 13QNs with correlation coefficients from 0.9910-0.9992. The limit of quantification was 0.255-3.322μg/kg. The recoveries were 69.18%-104.45% with relative standard deviations of 0.21%-10.98%. Conclusion The analytical method is simple, accurate, sensitive and suitable for the determination of 13quinolone (QNs) antibiobtics in swine muscle.

Abstract:A comprehensive analytical method based on UPLC-MS/MS was established for determination of sodium cyclamate in 30wine samples from markets. Methods UPLC separation was performed on an Acquity UPLCTM BEH C₁₈ column (2.1mm×100mm,1.7μm) with methanol-0.1% acetic acid(90+10) as mobile phase. Triple-quadrupole mass spectrometry analyzer was used for the qualitative and quantitative analysis. Results The limit of detection of sodium cyclamate was 10μg/L.The recoveries of Sodium cyclamate were 75.0%-105%, and the RSD was 10.5%-12.1%. Among 30wine samples, 13samples were found to contain sodium cyclamate, whose level was 0.027-891μg/ml. Conclusion The method is simple with high sensitivity and selectivity and suitable for the determination of sodium cyclamate in wine. The results indicated the presence of abuse of sodium cyclamate.

Abstract:To establish a new method for the determination of lead in whole blood by graphite furnace atomic absorbance spectrometry(GFAAS). Methods After the protein in blood was removed by 800μl solution of 40ml/L nitric acid mixed with 6ml/L hydrogen peroxide and centrifugal separation, the whole blood lead was determined by GFAAS using Pd(NO₃)₂ (1g/L) as matrix modifier. Results The linear range was 0-100μg/L, the detection limit was 4μg/L, the RSD was 3.4%-9.1%, and the recovery was 88.1%-110.3%. Conclusion The method was satisfying and had been successfully applied to the determination of lead in whole blood.

Abstract:ObjectiveTo understand the compliance and implementation of national food safety standard GB 10769-2010Cereal-based complementary foods for infants and young children among supervision, inspection and industries, and to provide information for future revision. MethodsField investigation was carried out to understand the comprehension and detection capacity for each part of the standard, collecting the main problems, comments and suggestions from supervision, inspection and industries. ResultsThe valid questionnaire recovery rate from supervision, detection and industries was 95.5%, 91.1% and 85.7%, respectively. Most responders thought the standard was overall reasonable. The most concerned part of the standard were the product classification, the essential nutrients, mycotoxins and contaminants. ConclusionThe standard was reasonable, but some indicators should be updated according to the new risk assessment results. Meanwhile, standard training should be strengthened, and the media should play a positive role in public education.\=

Abstract:To investigate 7food preservative residuals of pickled vegetables in bulk at retail market of Yantai, and provide scientific basis for customer making decisions for such product. MethodsThe residue content of 7food preservatives including sorbic acid, benzoic acid, dehydroacetic acid were detected by ultra performance liquid chromatography with photodiode array detector (UPLC-PDA). The quality of pickled vegetable was judged by GB 2760-2011. ResultsThe detection rate of benzoic acid was 99.7% (299/300), higher than that of sorbic acid which was 68.7% (206/300), while the detection rate of dehydroacetic acid was only 25.0%. There were 188samples exceeded the benzoic acid limit of GB 2760-2011, the maximum value was 5.31g/kg which was 4.3times higher than the limit. In addition, the maximum value of sorbic acid was 2.35g/kg, 2.3times higher than the limit. Olio had the highest residual level among 300samples. The parabens were not detected in this investigation. Conclusion The content of benzoic acid was the highest and the violation rate was also the highest. We should strengthen the supervision and monitoring to control food preservative used in pickled vegetables.

Abstract:To investigate the risk of excessive aluminum residue in jellyfish and research the way to deduce the content of aluminum in jellyfish products.MethodsThe content of alum and aluminum in 51batches of jellyfish products were determined according to SC/T 3210-2001and GB/T 23374-2009, respectively. The methods for aluminum reduction in jellyfish were studied by soaking the jellyfish in water or weak acid. The soaking conditions were optimized by orthogonal test consisting of three factors at three different levels.ResultsThe results showed that the content of alum in all samples were qualified, while the unqualified rate of aluminum was 100%. The results of orthogonal test showed that the aluminum residues (wet weight) could be reduced to 57mg/kg by soaking 20g jellyfish products in 500ml 1% acetic acid solution for 6hours. Conclusion The standards should be revised to keep accordance to ensure food safety. Weak acid soaking was proposed for ready-to-eat jellyfish processing, while vinegar soaking was more effective to reduce the health risk of excessive aluminum for non-ready-to-eat jellyfish.

Abstract:ObjectiveTo monitor the Salmonella contamination in the whole process of hatching,cultivation,slaughtering, processing,distribution and retail,and to analyze and assess the correlation between Salmonella and serotypes． Methods 802samples from 18segments,including soil,feces,chicken,slaughtering facility and the worker''s hands,were collected from breeding farm,broiler hatchery,slaughterhouse and supermarket．All samples were tested according to GB 4789.4－2010and the data were statistically analyzed with SPSS 17.0software． ResultsThe positive rate of Salmonella was 75% in the pool used for depilation,while it was 58.3%,49.4%,33.3％,5.6% in feces,chicken,cutting tool and anal swab,respectively．The detection rate for chicken embryo and transport vehicles was 0．Six serotypes were detected,with the highest detection rate in Salmonella Enteritidis and Indiara Salmorella the second quarter had the most diverse serotypes． ConclusionThe slaughtering and processing made Salmonella spread and the machine and pool used for depilation was the key of cross contamination．The positive rate had no significant difference(P>0.05)between seasons．\=

Abstract:To assess the potential risk of dietary exposure to sodium nitrite in Chinese population and provide scientific basis for food safety risk management. Methods Food consumption data combined with concentration of sodium nitrite in foods were employed for exposure assessment. The amount of sodium nitrite intake obtained in the present study was compared with the acceptable daily intake (ADI) established by the Joint FAO/WHO Expert Committee on Food Additives. ResultsThe average estimates of sodium nitrite dietary exposure of whole Chinese population was 0.021mg/kg BW/day (accounted for 30.0% of ADI), while high dietary exposures (e.g.97.5 th percentile) was 0.150mg/kg BW/day exceeding the ADI by 2.1times. The average estimates of dietary exposure of various gender-age groups didn’t exceed the ADI, while high dietary exposures were 0.1248-0.2750mg/kg BW/day exceeding the ADI by 1.8-3.9times. Satled vegetables and pickles were the main source of dietary sodium nitrite exposure(61.9% of the total intake.Conclusion The sodium nitrite dietary exposure of whole Chinese population was below the ADI. Sodium nitrite-containing food could be a risk for high consumption population (97.5th percentile). Changing dietary pattern and improving the food processing were important measures to reduce the sodium nitrite dietary exposure to in China.

Abstract:Information monitoring and analysis is highly important to foster food safety risk communication during routine and emergency response. This paper is aimed to share how food safety information disseminated through internet and various news outlets can be monitored and used in risk communication activities. The key points for establishing an effective system are also discussed.

Abstract:To determine chemical toxins in food poisoning and its contents fast and accurately, and provide a scientific basis for emergency response. Methods According to the investigation and processing principles for food poisoning, HPLC with column derivatization reaction and fluorescence detection were used for 2suspected food poisoning samples sent by local CDC following NY/T 761-2008. Results High concentrations of carbofuran(27.0and 5.4g/kg)were detected in white noodles and fried egg noodles vermicelli.Conclusion This chemical poisoning case was caused by carbofuran．

Abstract:The reproductive toxicity of genistein has attracted a certain attention from researchers worldwidely in recent years. Excessive intake of genistein may result in abnormal structure and function of reproductive system in animals (including male and female). However, the mechanism on which genistein impact on female reproductive system remains inexplicit. Oocyte, the physiological foundation to the normal reproductive function, has been considered as a potent target for exogenous chemicals. It is shown that genistein can interfere with the maturation process of mammalian oocytes, which may be one of the mechanisms of genistein’s reproductive toxicity.

Abstract:Aquatic food is a good nutrients source for human, but the contaminants and their hazzard has aroused much attention. Therefore, it will contribute to a more reasonable aquatic food consumption if risk-benefit assessment for aquatic food was carried out.