Abstract:Allergenic proteins of pacific oyster (Crassostrea gigas) were separated and the change of protein molecular weight and antigenicity after proteases treatment were studied.MethodsOyster allergenic protein was isolated by ammonium sulfate precipitation and Sephadex G-75. The oyster allergenic protein was hydrolyzed by animal protein hydrolysis enzyme, papain, and neutrase protease, respectively. The degrees of hydrolysis were assessed by OPA and SDS-PAGE methods. The change of allergenic protein antigenicity were detected by indirect competitive ELISA. ResultsOyster allergenic protein of 40 and 98 kD was separated and the 40 kD protein was used for further studies. The highest hydrolysis degree of (31.87±0.309)% was achieved by papain and the oyster allergy protein band was disappeared in SDS-PAGE analysis. While by animal protein hydrolysis enzyme and neutral protease, the proteolytic degree of oyster allergies were (24.13±0.153)% and (12.43±0.115)%, respectively. The indirect competitive ELISA analysis also showed that the antigenicity of protein were obviously decreased by hydrolysis with these three proteases.ConclusionAntigenicity of oyster allergenic protein could be effectively reduced by papain hydrolysis.

Abstract:To investigate the prevalence, molecular characteristics and potential pathogenicity of Shiga toxin-producing Escherichia coli (STEC) isolates in foods.MethodsShiga toxin-producing Escherichia coli were isolated from 355 different foods samples. The stx1/stx2 subtypes and virulent genes were detected by PCR. A multilocus sequence typing (MLST)scheme provided by E. coli MLST database was performed. ResultsEleven non-O157 STEC strains were isolated from 355 foods samples with 3 isolates harboring stx2a, 3 harboring stx2e, 1 harboring stx2b and 4 untypable for stx2, ehxA and saa genes were detected in 5 isolates, 2 isolates were positive for subA gene and 1 isolate was positive for katP gene. The 11 isolates belonged to 7 different STs with 1 new allele type and 1 new ST identified. The phylogenetic analysis showed that the STEC isolates from foods had the relatively close genetic relationships with HUSEC or main serogroups STEC strains.ConclusionSTEC exist in different foods which showed molecular diversity and had the potential to cause human diseases.Thus the detection and surveillance of STEC in foods should be enhanced to prevent the prevalence and outbreak of relative foodborne diseases.

Abstract:To study the current status of serotype and drug resistance in Vibrio parahaemolyticus in food poisoning, diarrhea patients and the environment in Haizhu district of Guangzhou.Methods17strains from food poisoning, 27 strains from sporadic diarrhea patients and 17 strains from the environment were identified with biochemical and serotyping tests. Antibiotic resistance test of the isolates was further performed. ResultsSeventeen strains from food poisoning could be divided into 6 serotypes, and the prevalent serotype was O3∶K6 (12/17,0.6%).Twenty-seven trains from diarrhea patients could be divided into 10 serotypes, and the prevalent serotype was O3∶K6 (17/27,3.0%). Seventeen strains from the environment could be divided into 11 serotypes, but the serotypes were scattered. In addition, there were three dual-resistantstrains, and one triple-resistantstrain in those 61 strains.ConclusionThe strains were on different levels of antibiotic resistance, and the prevalent serotype was O3∶K6 in Haizhu district of Guangzhou.

Abstract:To survey the drug resistance and the distribution of virulence gene in isolated Vibrio parahaemolyticus (VP) from the imported aquatic products at Ningbo port.MethodsThe 129 VP strains were isolated from imported aquatic products at Ningbo port and 15 antibiotics were used for drug resistance test by K-B test method. Polymerase chain reaction was used for testing the 4 virulence genes(tlh、trh、tdh、toxR)from VP.ResultsThe drug resistance rates of ampicillin, carbenicillin and cefradine were 90.70%, 98.45% and 51.17%, respectively. The drug resistance rates of kanamycin, cefalexin, cephazoline and cefuroxime were 1.55%, 13.18%, 2.33% and 20.16%, respectively. Medium sensitive rates of kanamycin, cefalexin, cephazoline and cefuroxime were 33.33%, 52.71%, 46.51%, 40.31%, respectively. All strains were sensitive to the 8 antibiotics (Tetracycline, doxycycline, amikacin, gentamicin, cefoperazone, ofloxacin, chloramphenicol, co-trimoxazole). The detection rates of trh, tdh, tlh and toxR genes were 0%, 0.78%, 100% and 100%, respectively.ConclusionThe doxycycline, gentamicin, co-trimoxazole were the preferred antibiotic for people infected by VP from the imported aquatic products. The rate of VP strains carrying main virulence gene was relatively low in VP strains in the imported aquatic products.

Abstract:A thorough study has been made to improve the national food safety standard framework and development mechanism. Some issues around the framework are addressed, including the scope and mandate of food safety standard, the responsible body of standard development, the procedure for the provisional limit, standard release form, the issues related to food additives, food packaging and functional food, food safety standards at local and enterprise level, etc. Some recommendations are provided based on the analysis.

Abstract:To study the effects of vitamin A fortified oat drinks on children's serum retinol level.Methods6-8 year-aged students from primary school were divided into two groups. All the sdudents had normal diets for one year and the intervention group drank 250 ml drinks everyday. Dietary vitamin A levels were calculated by 3-day 24 hour dietary recall method, and the serum retinol levels were also detected. ResultsStatistically significant differences of diatey vitamin A in intervention group of boys and girls were observed after intervention (P<0.05), butdiatey vitamin A in all groups were lower than the national standard before and after intervention.The dietary intakes of vitamin A in intervention groups were higher than those of control groupsafter intervention.No statistic were observed in serum retinol levels before intervention (P>0.05), while there were significant difference were observed after intervention (P<0.05).ConclusionVitamin A nutritional status of children from Beijing suburb district was insufficient, and vitamin A fortified oat drinks could improve retinol levels of the children.

Abstract:The fruit and leaf's toxicity of Phytolacca Americana L.were tested and evaluated by acute oral toxicity test in mouse, in vitro cytotoxicity test and C. elegans toxicity test.MethodsIn the experiment of acute oral toxicity test in mouse, the maximum limit method was used to test the leaf's toxicity and Horn's method to test the fruit's toxicity. In vitro cytotoxicity test was carried out on CHL cells using neutral red uptake method. C. elegans toxicity test was carried out after 24 h exposure using 96-well plates. ResultsBy acute oral toxicity test in mouse, it was proved that the leaf was no-toxic with the maximum tolerated dose no less than 20.00 g/kg BW and the fruit was actually no-toxic with LD50 greater than 10.00 g/kg BW. The fruit's toxicity was greater than the leaf's. In the in vitro cytotoxicity test, the leaf and the fruit's IC₅₀ were 7.4 and 5.6 μg/ml respectively. In C. elegans acute toxicity test, the death of the nematodes was not detected at the dose of 215.0 mg/ml after 24 h exposure to leaf, whereas the IC₅₀ of fruit was detected as 16.5 μg/ml.ConclusionIt was indicated that the Phytolacca Americana L. fruit's toxicity wasgreater than the leaf's using classic mouse and C. elegans exposure model. In the in vitro cytotoxicity model, the fruit's toxicity was a little higher than the leaf's with minor difference. It was suggested that C. elegans model had more practical potential than in vitro cytotoxicity model on toxicity screening.

Abstract:To explore the effect of natto powder on the immunological function in mice.MethodsNatto powder were consecutively orally administered to mice with different dosage for 30 d. Humoral immunity, cellular immunity, phagocytic system function and activity of natural killer cell were used to access the effect of natto powder on immunological function. ResultsNatto powder could stimulate proliferation and transformation of mice's spleen lymphocytes, promote delayed hypersensitivity, increase the quantity of antibody producing cells, enhance the level of serum hemolysin, accelerate the carbon clearance and intensify the peritoneal macrophage, and had no significant effect on activity of natural killer cell in mice.ConclusionIt suggested that natto powder could enhance the immune function in mice.

Abstract:Ara h1 is a major allergen proteins in peanut, which can make peanut allergic patients produce specific IgG and IgE. Ara h1 and the specific binding of IgG and IgE is an important cause of peanut allergy. ProteinA affinity chromatography and affinity chromatography with Ara h1 as a ligand were used to purify anti-Ara h1 IgG and IgE. Purified specific IgG and IgE antibodies have important significance for the study of allergen and antybody interactions.

Abstract:To establish the rapid and accurate determination method of Al、Cr、Mn、Fe、Ni、Cu、Zn、As、Se、Cd、Sb、Pb 12 metals in soy sauce by ICP-MS.MethodsCombined with the high salinity properties of soy sauce, an accurate determination method was established through means of sample matrix dilution、the appropriate isotope、the He collision cell pattern and internal calibration. ResultsThe linear range of 12 metals was 0.2 μg/L-1.0 mg/L, r>0.999,MDL was 0.001-0.003 mg/L, RSD < 10%, recovery rate was 80%-110%. ConclusionThe ICP-MS method was less interference、accurate、convenient and rapid for determination of metals in soy sauce and other high salt food.

Abstract:To establish a method for the determination of folic acid in fortified foods by high performance liquid chromatography (HPLC) with post-column photochemical derivatization.MethodsChromatographic separation was carried out using a SunFire C₁₈ column (4.6 mm× 250 mm, 5 μm). The mobile phases was acetonitrile and 50 mmol/L potassium dihydrogen phosphate solution (pH=5.0) with an optimized gradient elution. Post-column photochemical derivatization of folic acid was under UV-light irradiation at 254 nm. The fluorescence detection was performed with the excitation at 344 nm and the emission at 428 nm. ResultsThe linear range was 0.01-2.0 μg/ml, r=0.999 9. The limit of detection (LOD) was 0.01 μg/g and the limit of quantification (LOQ) was 0.03 μg/g. The average recoveries were 90.0%-98.0% and the RSD of the method was less than 5%.ConclusionThe method was simple, rapid, accurate, reproducible, and suitable for the determination of folic acid in fortified foods.

Abstract:A method for determination of raceanisodamine,scopolamine and()-hyoscyamine by LLE-GC-MS was established.MethodsDatura was filtered after ultrasonic extraction with 2 mol/L hydrochloric acid for 30 min. The filtrate was extracted three times with chloroform after adjusting pH to 9 with concentrated aqueous ammonia. The extract was evaporated to dryness and diluted to constant volume before determination. ResultsThere was a good linearity between the peak area and the concentration of raceanisodamine, scopolamine and()-hyoscyamine within the range of 0.1-0.5 mg/ml, the correlation coefficients were 0.998 1-0.999 5, the recoveries of spiked samples at 0.2 mg/ml and 0.4 mg/ml to flowers and leaves of datura were ranged from 76.7% to 119.0%, RSDs were ranged from 0.8% to 7.3%, and the detection limits were ranged from 0.1 to 1.0 μg/kg. ConclusionThe method was simple, rapid and reliable. It could be applied to determine raceanisodamine, scopolamine and()-hyoscyamine in datura.

Abstract:To establish a method for simultaneous determination of kojic acid and 2-mercapto-5-methyl-1,3,4-thiadiazole (MMTD) in flour and flour improver by HPLC.MethodsSeparation was achieved on an Atlantis C₁₈ column (4.6 mm ×15 cm, 5 μm) with the mobile phase of acetonitrile and 0.1% phosphoric acid solution. Gradient elution was used with the flow rate of 1.0 ml/min. The injection volume was 1μl and the detection wavelength was 269 nm for kojic acid and 300 nm for MMTD. Kojic acid and MMTD in samples were extracted by acetonitrile. After centrifugation and filtering, sample solutions were analyzed by HPLC. ResultsKojic acid and MMTD both showed good linearity in the range of 0.5-20 μg/ml. The average recoveries were in the range of 84.2%-92.4% (RSD 1.1%-6.9%, n=6). Limit of detection (LOD) of kojic acid and MMTD were 2.0 and 0.7 mg/kg, respectively.ConclusionThe method can be used for the determination of kojic acid and MMTD in flour and flour improver.

Abstract:To optimize gas chromatography and mass spectrometry conditions, establish a method for determination of 16 phthalic acid esters in juice using gas chromatography-tandem mass spectrometry (GC-MS/MS), and investigate the contamination level in juice in Anyang City.MethodsThe samples were extracted by hexanes, purified with ProElut PSA Glass column, concentrated by nitrogen drying and then determined by GC-MS/MS using external standard method. Results16 phthalic acid esters were separated completely within 24 minutes. The linearity of 16 phthalic acid esters was 5-5 000 μg/L with correlation coefficients (r²) above 0.99. The relative standard deviations (RSDs) were in the range of 0.1%-6.1%. Recoveries ranged from 78% to 106% for all compounds at three different spiked levels. The limits of detection were 0.1-0.5 μg/L.Conclusion16 phthalic acid esters were better separated in the suitable conditions of gas chromatography. Choosing the highest and most abundant mass precursor ion and the best collision energy, the detection of product ion by GC-MS/MS could reduce the background and improve the sensitivity. The method was simple, accurate and sensitive. It was suitable for the determination of phthalic acid esters in juice.

Abstract:The cefalexin residues in milk was rapidly and quantitatively detected by fluorescent immunochromatography assay and strip reader.MethodsThe europium nanoparticles were synthesized by RP-microemulsion technology. The Eu nanoparticles conjugated with cefalexin monoclonal antibody was used as a fluorescent label. The cefalexin-ovalbumin and goat anti-mouse IgG was respectively used as the test line and control line on the fluorescent strip. A rapid and quantitative fluorescent immunochromatography assay for detection of cefalexin residues in milk was established equipped with a strip reader. ResultsThe fluorescent immunochromatography assay had a good correlation with ELISA, with the detection limit of 0.16 ng/mL, and the IC₅₀ value was 0.6 ng/ml. The linear detection range was 0.16-5 ng/ml. The recoveries of spiked milk were between 100%-115%, and the cross-reaction rate of the antibody with 12 kinds of antibiotics including cephalosporins and penicillin was less than 0.01%.ConclusionIt was easy, rapid, and sensitive for the detection, and had the potential to be a powerful tool for screening other antibiotics residues in milk and milk products.

Abstract:To establish a method for determining 14 organophosphorus pesticides(OPs) and 7 pyrethroids pesticides (PPs) in 5 kinds of food by GPC and GC-MS/MS, and find the advantages of GPC and GC-MS/MS in analyzing pesticide residues in food.MethodsFive kinds of food including leeks, Chinese cabbage, pepper, pork and fish were pretreated with GPC, and the samples were analyzed qualitatively and quantitatively by GC-MS/MS. ResultsThe linear correlation coefficients of 14 OPs and 7 PPs were above 0.995. The limit of quantification was in the range of 0.002-0.034 mg/kg. The relative standard deviation (RSD) was 2.9-10.2%, and the rates of recovery were 78.6-108.3% for leek and pork samples spiked with 0.05,0.10 and 0.20 mg/kg of 14 OPs and 7 PPs. ConclusionThe method was widely used, highly sensitive, reliable, accurate, and suitable for analysis of pesticide residues in many kinds of food.

Abstract:To establish a high performance liquid chromatography (HPLC) method of simultaneous detection of 11 kinds of artificial pigments including Tartrazine, New red, Amaranth, Carmine, Sunset yellow, Allura Red, Red 2G, Acid blue 9, Azorubine, Erythrosine and Acid orange II, et.al. MethodsThe target compounds in food samples were extracted by ethanol ammonia and purified by WAX cardge. The extracts were determined by a high performance liquid chromatography-diode array detector. ResultsThe results showed that there were good linear relativities (r>0.999) between artificial pigments and absorbance in the content ranging from 1.00 to 20.0 μg/ml. The limit of detection, recovery rate and standard deviation were 0.02-0.06 mg/kg, 81.1%-100.8% and 1.3%-4.9%, respectively (n=6). The detection rate of various pigments in 259 food samples ranged from 0%-22.0%.ConclusionThe method was selective, sensitive and repeatable, and compatible for simultaneous detection of 11 kinds of artificial pigments.

Abstract:To evaluate the feasibility of detecting bacterial contamination for cold dish by ATP bioluminescence assay, and to provide the scientific basis for food hygiene fast detection.MethodsATP bioluminescence assay and standard plate counting method were used respectively to detect 80 cold dish from 20 restaurants. ResultsComparing with the standard plate counting method (cfu/g), the false positive rate of the ATP bioluminescence assay (cfu/g) was 18.8% and the false negative rate was 20.4%.ConclusionIt was feasible for rapid preliminary test and evaluation of bacterial contamination by ATP bioluminescence assay at cold food institutions.

Abstract:To develop a scientific and index for the local government food safety supervision evaluation.MethodsUsing analytic hierarchy process(AHP), evaluation index comparison table was designed, the supervision personnel from different governmentdepartments at all levels was invited to fill in the tableindependently according to his judgment. The weight and score of evaluation index was analyzed and calculated by summary analysis. Results① The weight of 8 level-one index including improvingthe institutional mechanisms, cracking down on crimes, urging the enterprises to implement their responsibility,status of food safetypriorities, food safety accident treatment, food safety information disclosure, publicity and educationand award report was 21.3%, 16.4%, 14.7%, 13.5%, 13.2%, 7.3%, 7.1% and 6.5%; ② The weight and score of level-two index was also calculated; ③ The AHP score and the original score were coherent with several exception; ④The institutional mechanism, cracking down crimes, urging the enterprises to implement their responsibility would be the priorities of local government.ConclusionGroup decision-making scoring using analytic hierarchy process was more scientific, objective and operable.

Abstract:In order to understand the processing status of instant raw aquatic products in Jiangsu restaurant industry and provide the basis to develop the good manufacture practices. MethodsUsing epidemiological cross-sectional survey, stratified random sampling method was performed in field investigation of the restaurants offering instant raw aquatic products. ResultsThe species of instant raw aquatic products in Jiangsu restaurant industry was abundant, the passing rate of critical control point in the processing cycle was low. For example, only 10% of the inspected restaurant set up the special room for processing. Personnel management and health management did not come up with the requirements of instant raw aquatic products.ConclusionThe health status of instant raw aquatic products in Jiangsu was questionable. To improve the food safety of instant raw aquatic products, the needs of GMP, strengthening daily management and personnel training, regulating the processing cycle was urgent.

Abstract:To investigate the contamination of Bacillus cereus in infant formula milk powder and cereal-based complementary foods from Shijiazhuang market, and also to monitor the toxin genes of the isolated strains.MethodsInfant formula powder and cereal-based complementary foods from 23 counties of Shijiazhuang city were collected. Bacillus cereus strains were tested and counted according to the national standard GB/T 4789.14-2003 and foodborne pathogenic bacteria monitoring manual. The hemolytic toxin genes and non-hemolytic toxin genes of isolates were detected by real-time PCR. Results85 strains of Bacillus cereus were detected from 399 samples. The detection rate of infant formula powde was 20.3%(36/158) and cereal-based complemenary foods was 22.8%(49/241). The hemolysin gene was positive in 48 isolated strains and the detection rate was 56.5% with no isolates carrying non-hemolytic toxin gene.ConclusionThe contamination of Bacillus cereus in infant food was quite severe. These foods had a potential food poisoning risk. Our results could provide reference for the infant food hygiene inspection standard setting, supervision and management.

Abstract:To investigate the heavy metals contamination in food in Henan Province in 2010.Methods3 657 samples of 8 kinds were collected from 18 cities in Henan Province in 2010. The contamination of lead, cadmium and mercury were analyzed respectively according to the standard of GB/T 5009.12-2003, GB/T 5009.15-2003 and GB/T 5009.17-2003. The results were evaluated according to the standard of GB 2762-2012. ResultsThe average level of lead, cadmium and mercury in food were 0.34,0.054 and 0.077 mg/kg, and the violation rates were 8.8%, 3.9% and 8.3%, respectively. The violation rates of lead in cereals, meat and vegetable were 17.2%, 14.5% and 10.7%, respectively; those of cadmium in edible fungus and eggs were 9.6% and 8.1%; and those of mercury in vegetable and cereals were 25.3% and 12.3%.ConclusionThe lead and mercury contamination in food was serious in Henan Province, especially in cereals, vegetables and meat. There was an urgent need to strengthen the monitoring and supervision on food safety.

Abstract:The status and problems of national standards of microbiological examination has been summarized. 163 food standards of microbiological examination have been discussed and reviewed respectively by technical experts during the clean-up program. As a result, a catalogue of 31 food safety standards for microbiological examination (GB 4789) was proposed. In order to provide a better recognition of the clean-up program and comprehension of the construction approaches on food safety standard system for the administration department and food industry, this paper explores the problems of current standards and the corresponding solutions on the basis of summarizing and analyzing results of the clear-up program. The paper also provides solutions for the standards integration program and following improvement of standard system construction.

Abstract:With the rapid development of medical research, the Caenorhabditis elegans, a model organism, are increasingly applied in the studies of human diseases. This paper reviews the research progress in this field.

Abstract:From the perspective of food poisoning prevention and control, this article focused on the background value, source, biological metabolism and safety standard of cyanide in food, and provided references for rapid response of public emergency events and food safety risk assessment.