Abstract:In order to investigate the effects of different dietary protein species intake on plasma homocysteine concentration in rats.Methods 48 Wistar rats were fed with casein, lactalbumin, egg albumin, SPI, wheat gluten and zein diets for 10 days, and sacrificed to collect blood sample for analyzing the concentration of plasma homocysteine, cysteine, GSH and Cys-Gly.Results Body weight gain of wheat gluten group was significantly lower than casein, lactalbumin, egg albuminand and SPI, while negative growth was observed in zein group(P＜0.05). The plasma homocystein concentration of wheat gluten and zein group was significantly lower than other groups, and the plasma homocystein concentration in lactalbumin group was significantly lower than casein group.Conclusion The effects of different dietary protein species intake on plasma homocysteine concentration mainly depends on protein species and the contents of amino acid. The main mechanism is that the increased cysteine concentration promote enzyme activities of homocystein metabolism, and increase the consumption of homocysteine.

Abstract:To investigate the effect of limiting amino acid on plasma homocysteine concentration in rats by adding lysine and threonine to wheat gluten.Methods 32 Wistar rats were fed 25S, 25C, 29G and 29GLT diets with different dietary protein species for 14 days. At the end of the experiment, the rats were sacrificed, and blood and liver samples were subject to biochemical analysis. Results Body weight gain in rats fed with wheat gluten dietary was significantly lower than casein and soybean protein dietary, but the decrease in body weight gain was significantly suppressed by adding lysine and threonine. The plasma homocysteine concentration in rats fed with wheat gluten was significantly lower than casein, however the decrease in wheat gluten group was recovered to the level of 25C and 25S by lysine and threonine. Lysine and threonine also suppressed the plasma S-adenosyl methionine (SAM) activity and liver homocysteine betaine methyltransferase (BHMT) activity, but had no effect on the cystathionine beta synthase (CBS) activity. Plasma homocysteine (Hcy) content did not decrease in the soybean protein group with low methionine.Conclusion The effects of wheat gluten on plasma homocysteine concentration may depend on the contents of amino acid. The high level serine and low level lysine and threonine in wheat pluten may lead to the decrease of plasma Hcy content.

Abstract:To investigate the molecular characteristics and antibiotic resistance of nontyphoidal Salmonella isolated from food in Beijing.Methods A total of 100 strains were isolated from foodborne pathogenic bacteria monitoring network in Beijing from 2004 to 2010, and were analyzed by PFGE and antimicrobial susceptibility test. Results The isolates were divided into 62 PFGE pattern, and each contains 1-11 strains. The result of antimicrobial susceptibility test showed that 55 strains were resistant to at least one antibiotic, including 15 multidrug resistant strains. The resistance rate to the eight antibiotics were nalidixic acid (40%), tetracycline (30%), chloramphenicol (15%), gentamicin (10%), trimethoprim/sulfamethoxazole (10%), ciprofloxacin (9%), cefoxitin (1%), and cefotaxime (0%).Conclusion PFGE profiles, antibiotic resistance patterns and serotypes of Salmonella showed high consistency. The antibiotic resistance of foodborne nontyphoidal Salmonella in Beijing was serious, and enhancing the joint monitoring of molecular subtyping and antibiotic resistance has significant importance.

Abstract:The purpose is to evaluate the effects of di-2-ethylhexyl phthalate (DEHP) on the spatial learning and memory of offspring rats and on expressions of hippocampal synaptic plasticity related genes in rat's hippocampi by lactation exposure and explore the molecular mechanism of this process.Methods Mated female rats were assigned to four groups of 8 animals each based on a weight-balanced random allocation scheme after copulation. Mated female rats were administered different concentrations of DEHP (0,5, 50,0 mg/kg BW) by oral gavage with a metal catheter from PND 1 through PND 21. Spatial learning and memory were measured continuous 6 days for young adults (PND 65 days to 70 days) with Morris water maze and the effects on expressions of hippocampal synaptic plasticity related genes mRNA in rats′ hippocampi were detected by Real-Time PCR. Results In the location-navigation test in Morris maze,the latency time of 500 mg/kg BW group was longer than control group, and there was statically significant difference (P<0.05). In the spatial probe test, the distance percent in the target quadrant, time percent spent in the target quadrant and the frequency of crossing platform of 500 mg/kg DEHP group were less compared with control group (P<0.05). According to the data of Real-Time PCR, comparing with control group, the expressions of hippocampal synaptic plasticity related PSD95, CREB, PKA and CAMKII mRNA in 50 and 500 mg/kg BW groups were significantly down-regulated respectively (P<0.05). The expression of hippocampal synaptic plasticity related BDNF was down-regulated in 500 mg/kg DEHP group compared with control group (P<0.05).Conclusion Lactation exposure to DEHP (500 mg/kg BW) could produce developmental neurotoxicity and has effect on spatial learning and memory of offspring rats. The inhibition of expressions of hippocampal synaptic plasticity related genes such as PSD95, CREB, PKA, CAMKII and BDNF could be the mechanism of this process.

Abstract:To develop a real-time PCR method for detection of norovirus GⅡ in fresh strawberry, evaluate the application of magnetic beads enrichment method and PEG precipitation in detection of norovirus GⅡ and to detect norovirus GⅡ in 18 fresh strawberries from Beijing market.Methods Specific primers and probes were synthesized referenced to ISO/TS 15216-1. Magnetic beads and PEG precipitation were used to virus enrichment, and real-time PCR method was developed.Results The maximum recovery of magnetic beads enrichment and PEG methods were 1.730% (PBS buffer) and 1.682% (TGBE buffer) respectively. All 18 samples tested were negative.Conclusion The two virus enrichment methods developed in this study were suitable for the detection of norovirus GⅡ in fresh strawberry.

Abstract:Loop-mediated isothermal amplification (LAMP) method was developed to detect porcin, duck and sheep-derived materials in meat products (lamb chops, lamb meat roll, lamb shashlik).Methods A set of four specific primers (F3, B3, FIP, BIP) and two loop primers (FLP and BLP) were designed, respectively. Optimization reaction was confirmed, and two different measurement platforms were compared. 29 samples of meat products were collected from local markets and the detection of porcin, duck and sheep-derived materials was carried out.Results The optimized condition was 0.2 μmol/L each of F3 and B3, 1.6 μmol/L each of FIP and BIP, 0.8 μmol/L each of FLP and BLP, 1 mol/L betaine, 6 mmol/L Mg²⁺, 1.6 mmol/L dNTP. The limit of detection was up to 0.5% animal-derived materials in meat products under the platform of real time fluorescence and nake-eye inspection with SYBR Green I. The current results of LAMP obtained on the two measurement platforms were in good accordance. With the LAMP assay, meat products were successfully screened for porcin, duck and sheep-derived materials.Conclusion This method is a highly specific and sensitive detection system, and could be a very useful tool for animal components detection.

Abstract:A method for the simultaneous determination of 34 pesticides in urine by QuEChERS coupled with on line gel permeation chromatography-gas chromatography-mass spectrometry (GPC-GC/MS) was developed.Methods The effect of extraction and purification which the extraction and combinations of sorbent involved were investigated. The identification and quantification were performed by GPC-GC/MS in SIM mode and external standard method. Results The LOD of this method ranged from 0.05-3.2 μg/kg (S/N=3) in urine, the average recoveries of 34 pesticides for samples spiked at 0.05 μg/g ranged from 81.1%-108.8% with the relative standard deviations (RSD,n=6) less than 10.4%.Conclusion The convenient operation and versatility of this method is suitable for the fast screening and detection of 34 pesticide residues in urine.

Abstract:To establish a method of extraction and contentanalysis by acetylacetone spectrophotometry for formaldehyde in several edible mushrooms.Methods Mushroom samples were extracted by steam distillation with the distillation unit of Kieldahl azotometer instead of direct distillation. Furthermore, the effects of enzyme inactivation, soaking time and temperature on formaldehyde extraction were studied.Results Both in fresh and dried mushroom samples, formaldehyde could be fully extracted in several minutes by direct steam distillation after triturating, and the exact contents of formaldehyde were reflected by the extraction treatment. The linear range for formaldehyde was 0-1 μg/ml, and the method showed good accuracy with RSD＜10% (n=5) and recovery rate ranged from 82.10% to 97.98%.Conclusion The method established in the study is efficient, simple, accurate, precise and suitable for analysis formaldehyde contents in a variety of edible mushrooms.

Abstract:A evaporative light-scattering detector(ELSD)-hydrophilic interaction liquid chromatographic method was developed for determination of sodium glutamate in monosodium glutamate and chicken essence.Methods A Venusil HILIC (4.6 mm×250 mm, 5 μm) column at 30 ℃ was used to separate the target compound. 0.02 mol/L ammonium acetate (glacial acetic acid adjust pH=4.5)-acetonitrile (20∶80, V/V) was used as mobile phase with the flow rate of 1.5 ml/min. The target compound was detected by ELSD. Water was used for ultrasonic extracting sodium glutamate in samples. The solution was analyzed by HPLC after filtration. Results Sodium glutamate showed good linearity with the detection range of 6.0-20 g/L. The spiked recoveries into monosodium glutamate and chicken essence were respectively 98.5% and 94.7% and relative standard deviations (RSDs) were respectively 1.07% and 2.14% (n=5).Conclusion The method could be used for determination of sodium glutamate in monosodium glutamate and chicken essence.

Abstract:To develop an analytical method for the determination of 26 β-agonists in animal liver tissue based on ultra pressure liquid chromatography tandem mass spectrometry (UPLC-MS/MS).Methods Pig liver and duck liver were extracted using trichloracetic acid solution. Then the extract were purified and enriched by Oasis MCX solid phase extraction cartridges. Target compounds were separated on a Waters ACQUITY UPLCTM BEH C₁₈ column with gradient elution using methanol and water containing 0.1% formic acid. Quantification was performed with matrix-fortified standard calibration.Results Average recoveries of 26 β-agonists spiked at three concentrations ranged from 76.4% to 115.4% with relative standard deviation lower than 15.0%. The limits of quantitation (LOQs) for the method ranged from 0.1 to 0.7 μg/kg.Conclusion Due to its high sensitivity and good reproducibility, the method is suitable for the determination of target agnoists in animal liver tissue.

Abstract:Food safety risk monitoring is a risk management measure based on the principle of risk analysis, promoted by international organizations and been proved successful in many countries. China began to set up and implement the national food safety risk monitoring system in 2010, but still has a lot of deficiency and shortcomings in system building, sector involvement, plan and scheme developments and the result application. Based on the experience of developed countries and international organizations, and from the angle of purpose, characteristics and requirements of risk monitoring, we put forward the suggestions on establishing a risk monitoring work plan, further improving the participation mechanism and information communication using mechanism. Specific suggestions for improvement of the food-borne disease surveillance are also put forward.

Abstract:To test the foodborne pathogenic bacteria examining capability of monitoring institutions, ensure the accuracy and comparability of the results, and to improve the quality of monitoring.Methods The blind samples were prepared by adding two to three kinds of foodborne pathogenic bacteria (Salmonella, Staphylococcus aureus, EHEC, and Enterobacter sakazakii) to radiation-sterilized milk powder. After stability tests, the samples were delivered to monitoring institutions. The results were evaluated with point-score-system and analyzed with Pearson χ² test. Results 319 monitoring institutions, which was 97.6% of the total number, reported their results. 299 institutions reported a qualified result, and the qualified rate was 93.7%. The false negative rates of the four bacteria were different, among which Enterobacter sakazakii was much higher than the other three. There was no statistical difference in qualified rates between institutions that joined the monitoring network before 2010 and those who joined later, or between provincial and municipal CDC.Conclusion The quality control program had provided scientific data for relevant laboratory trainings. It also proved that the capability of the laboratories meet the requirements for foodborne pathogenic bacteria monitoring.

Abstract:To analyze the current situation of functional food advertising, especially illegal advertising, and provide recommendations of targeted strategies.The functional food advertisement was analyzed through quantitative approach using supervision data of the past few years.The obstinate illegal advertising resulted in the following reasons:the separation of approval, supervision and punishment, lack of audit by the media, and poor administrative efficacy.The strategies includes perfecting the laws and regulation, specifying the responsibility of departments, reinforcing monitoring and supervision capability.

Abstract:To survey the contamination and virulence gene profiles of B.cereus isolated from retail infant formula in China.Methods Infant formulas were quantitatively detected for B.cereus using MPN method. Virulence genes in relation to emetic and diarrheal toxins production harbored by B.cereus were detected by multiplex PCR. Results Fifty-seven out of 135 infant formula samples were positive for B.cereus with the contamination rate of 42.22% and the mean contamination level of 7.14 MPN/g. The contamination of B.cereus in domestically produced infant formula was more severe than those imported one. B.cereus contamination of infant formula sold online was more serious than that collected from supermarket. A total of 24 toxigenic patterns in B.cereus were found. Most of B.cereus isolates carried nhe gene (92.98%) and entFM gene (71.93%). There were 40 (70.18%) strains that carried both nhe and entFM genes simultaneously. Subtyping results demonstrated that the frequency of nheA, nheB, nheC were 88.72%, 88.72%, 49.12%, and hblA, hblC, hblD were 24.56%, 22.81%, 17.54%, respectively. The frequency of cytK occurrence was 22.81%. There were 8 strains that carried all three subtypes of both nhe and hbl genes, which indicated that these strains may be highly toxic.Conclusion Retail infant formulas were heavily contaminated by B.cereus. Most isolates carried one or more virulence genes. It is recommended to broaden the monitoring for B.cereus in infant formulas. It is necessary to make an assessment of infant dietary exposure to B.cereus in order to establish the national standard of maximal limit for B.cereus in infant formula.

Abstract:To investigate the contamination of aflatoxin B₁ in food and oil in Guangzhou, and provide the basic data of dietary intakes of aflatoxin B₁ for food safety assessment.Methods The samples of seven kinds of food including rice, wheat flour, peanut and corn oil, peanut, corn flour, fried food and soybean from ten regions were collected randomly from farmer's markets, supermarkets, wholesale markets, and catering units. The national standard detection method for aflatoxin B₁ (ELISA) was taken to detect the content of aflatoxin B₁. Results 260 samples were detected aflatoxin B₁ and the detection rate was 31.71%, and the farmer's markets had the highest detection rate. The detection range was 0.025～39.300 μg/kg, with the mean value of 2.675 μg/kg and the median of 2.5 μg/kg. The overall qualified rate was 98.66%.Conclusion The overall level of aflatoxin B₁ contamination in market food was low, but some foods such as vegetable oils (peanut, corn) should be more concerned.

Abstract:To investigate the foodborne pathogenic bacteria contamination in aquatic products in Guangzhou, and provide the science base for foodborne disease surveillance.Methods The monitoring data of 1 602 aquatic products from 2006 to 2013 were analyzed for foodborne pathogenic bacteria. Results The total detection rate was 21.16%, and the detection rates of Vibrio parahaemolyticus, Vibrio vulnificus, Salmonella, Listeria monocytogenes, and Vibrio cholerae were 19.54%, 8.63%, 1.08%, 0.59% and 0.14% respectively.Conclusion The major contamination of foodborne pathogenic bacteria in aquatic products in Guangzhou was still Vibrio parahaemolyticus, but the contamination of Vibrio vulnificus, Listeria monocytogenes and Salmonella also should not been ignored.

Abstract:To understand the rhodamine B's content in chilli(dry) and ground chilli peppers in China, analyze the possibility of the illegal use of rhodamine B, and provide the data support to judge the economically motivated food adulteration of rhodamine B.Methods Chilli(dry) and ground chilli peppers were collected from small restaurants, supermarkets and farmer's markets using random sampling method. All samples were detected on an liquid chromatography-tandem mass spectrometry. Results 72 samples were positive in 2 107 samples, including 21 chilli(dry) and 51 ground chilli peppers samples. The content range was between 0.2×10-3 and 11.9 mg/kg, and the contents in chilli(dry) were all less than 0.1 mg/kg. In chilli peppers, the contents of 23 samples were less than 0.1 mg/kg, 12 samples were ranged from 0.1 to 0.5 mg/kg, 13 samples were ranged from 0.5 to 5.0 mg/kg, and only 3 samples were greater than 5.0 mg/kg. The highest detection rate was from farmer's markets and in bulk.Conclusion Rhodamine B was detected in chilli(dry) and ground chilli peppers in China. Considering the background values of rhodamine B caused by plant enrichment, the content of above 0.1 mg/kg was recommended to judge adulteration.

Abstract:This study was conducted in order to understand the current status of microbial contamination on instant food in Jiaxing City, identify the high-risk food and provide scientific basis for the prevention and control of foodborne disease.Methods 8 kinds of frequently consumed instant food were collected from farmers' markets, supermarkets and restaurants for microbial contamination detection. Results 56 pathogen strains were identified in 640 food samples,with positive rate of 8.75%. Among the positive samples, the detection rate of Vibrio parahaemolyticus was the highest (69.64%), followed by Staphylococcus aureus (14.29%), Listeria monocytogenes (8.93%), Bacillus cereus (5.36%) and Vibrio vulnificus (1.79%). The peak season of pathogen contamination was the third season with detection rate of 12.50%. High contamination rate was found in foods from farmers' markets, bulk food and aquatic products, with detection rate of 17.60%, 13.30% and 25.00%, respectively.Conclusion There was a potentially high risk of microbial contaminations on instant foods in Jiaxing City. Measures should be taken such as more stringent health supervision, better practices in food operation and more food hygiene publicity to the public, which could help to reduce the risk of foodborne diseases.

Abstract:To investigate the phthalates contamination status of white spirit of Yantai, and to ensure food safety of consumers.Methods According to detection methods of National Food Contamination and Harmful Factors Risk Workbook and GB/T 21911-2008,6 types of phthalates (DIBP、DBP、DMP、DEHP、DEP、DPP,et al) were detected in 35 white spirit samples. Results The detection rate of DIBP and DBP were 65.71%, and the highest content of DBP was 2.14 mg/kg. The detection rates of DMP, DEHP, DEP and DPP were 25%, 20%, 8.5% and 2.85%, respectively. The average contents in descending order were DIBP(0.404 mg/kg), DBP(0.396 mg/kg), DEHP(0.216 mg/kg), DEP(0.206 mg/kg), DMP(0.104 mg/kg), and DPP(0.0546 mg/kg).The other phthalates were not detected.Conclusion The white spirit generally contained a variety of PAEs, and the monitoring and supervision should be strengthened.

Abstract:The result of food safety risk assessment is the scientific basis for formulating and revising the food safety standards, and exercising food safety supervision and administration. Therefore, the accuracy and reliability of the result of risk assessment will affect the decision making of food safety risk management. Risk assessment methods, statistic parameters, models and health-based guidance values are some of the most important parameters that affect the result of risk assessment. Meanwhile, there are some misunderstandings and incorrect use of these parameters. This paper discussed the choices and usage of these parameters in the risk assessmentof food chemicals.

Abstract:To assess the health risk of exposure of ethyl carbamate from rice wine among population in five Chinese southeast provinces and municipalities.Methods The simple distribution method was introduced in dietary exposure assessment of ethyl carbamate derived from rice wine consumed by population aged 18 and above. Subsequently, their health risk assessment was conducted. The consumption data of rice wine from Chinese Nutrition and Health Survey (2002) and the ethyl carbamate concentrate data from a survey in 2010 and 2011 were adopted in dietary exposure assessment. Results The mean and maximum values of ethyl carbamate in rice wine sample were 0.103 and 0.498 mg/kg respectively. The average intake of ethyl carbamate and the margin of exposure (MOE) value among population aged 18 and above were 13.4 ng/kg BW per day and 22 388 respectively. In addition, the average intake of ethyl carbamate in rice wine of consumer only was 427.8 ng/kg BW per day. Therefore, the margin of exposure value was 701.Conclusion For the population aged 18 and above, the health risk caused by ethyl carbamate intake from rice wine was quite low, however, it was rather high among population who consume the rice wine in large quantities.

Abstract:To assess the potential acute and chronic health risk of oral exposure to methanol in tequila in Chinese adult drinkers.Methods Oral exposure threshold limit values in human were chosen by toxicity data. A conservative estimation was used. Instead of high percentile tequila consumption data, high percentile distilled spirit consumption data combined with 3.0 g/L (100% ethanol) methanol in tequila as the maximum concentration were employed for acute exposure assessment. Instead of average tequila consumption data, average distilled spirit consumption data combined with 1.8 g/L (100% ethanol) methanol in tequila reported by reference published were employed for chronic exposure assessment. Results The estimated single intake of methanol from tequila was 11.25 mg/kg BW which was lower than single oral exposure dose (20 mg/kg BW). The estimated intake of methanol from tequila was 1.69 mg/kg BW which was lower than the recommended reference dose of 2.0 mg/kg BW.Conclusion Acute and chronic health risk of methanol from Tequila was ignorable.

Abstract:To identify the source and risk factors of the food poisoning event.Methods A epidemiology survey was carried out according policy. Results 8 of 9 people developed patient (88.89%). The main symptoms of the poisoning are nausea, frequent vomiting, dizzy and stomachache. The breakfast on 16^th May was doubtful. The wild vegetable was doutful poisonous food.Conclusion This food poisoning event was caused by hellebore. The authors have put forwards their points and suggestions.

Abstract:It is widely accepted in the world to prioritize the food, microbiological hazards and its combinations using risk ranking techniques before food safety supervisions and quantitative microbiological risk assessments were performed, however there is no universal methodology available for risk ranking. The present study reviewed the published risk ranking framework for food microbiological hazards, figured out their disadvantages and put forward an opinion to build a quantitative risk ranking model for microbiological hazards based on risk surveillance data.

Abstract:With the diversification of food, the benefit of food is nutrition, while it also brings risk. Risk-benefit assessment in food and food ingredients is a new area in food safety. In recent years, risk-benefit assessment were used in clinical, microbiological, environmental and ecological research, but undeveloped in food area. In this review, the existing international risk-benefit assessment is reviewed, and the application in China is prospected.