Abstract:To investigate the characters of nerve differentiation procession induced from mouse embryonic stem cells(ESCs) through lineage selection method and then develop the neural differentiation model in vitro.Methods Dopaminergic neurons development model was induced from undifferentiated ESCs through pendent drop and suspension culture, lineage selection culture,neuron-like cells proliferation and differentiation culture of nerve cells. The morphology was observed and the detection of characteristics of neural specific genes and proteins expression at various differentiation stages was performed by RT-PCR and immunofluorescence and immunochemistry. The secretion ability of neurotransmitter dopamine at each stages was detected by high performance liquid chromatography(HPLC).Results With the extending of differentiation time,numerous neuron-like cells were observed in differentiating cells and some neuron structures including synapses were clearly visible in the later differentiation period.In initial differentiation period,only a limited number of neural specific genes and proteins were expressed in low levels while all relating genes and proteins expressed in significantly increased levels with culture proceeding.The neurotransmitter dopamine had not been detected in the undifferentiated and initially differentiating stages but there was a remarkable rising trend in later period.Conclusion The cells acquired from the ESCs differentiation using ITSFn culture has the properties of dopaminergic neurons and this is an available model for developmental neurotoxicity research.

Abstract:To assess the neurobehavior and cognitive ability of rat offspring exposed to yttrium nitrate.Methods Pregnant rats were orally exposed to yttrium nitrate by garage at 0,5, 15 or 45 mg/kg BW dose from gestation day (GD) 6 to postnatal day (PND) 21, then offspring were given the same dose until PND 63. The indexes of body weights, food consumption, organ weights and neurobehavior test results such as hot plate, motor activity and Morris water maze test were recorded. Results All yttrium-exposed male offspring showed a significantly increased body weight on PND 21. However, male offspring body weight of 45 mg/kg BW dose decreased significantly from PND 42 to the end of the experiment (P<0.05), which caused a lower weight change and overall food consumption (P<0.05), but all groups showed similar feed conversion ratios. The differences on other body weight and relative brain weight between treated and control groups were not considered treatment-related. The only significant difference in Morris water maze test was the high dose female offspring which showed a higher latency on the fifth day (P<0.05), and similar results were observed among other neurobehavior tests.Conclusion Continual exposure of yttrium nitrate could cause a decline in the body weight of high dose male offspring, but would not affect the brain weight. Moreover, no differences were found in tests of hot plate, motor activity and Morris water maze test.

Abstract:To understand the distribution of Escherichia coli in poultry and to reveal the drug resistance and molecular epidemic and characteristics of isolates from Shandong Province, and to provide science basis for the risk assessment.Methods A total of 42 E.coli isolates were analyzed with drug sensitivity test for 13 antimicrobial agents, and analyzed with PFGE and MLST genotyping. Results The PFGE genotyping of 42 isolates yielded 34 PFGE types. MLST analysis of isolates identified 18 STs, and the 7 housekeeping genes had different variation. All isolates were resistant to two or three antimicrobial agents, and the highest resistance was to AM, SXT and NOR, which was 97.62%、92.86% and 90.48%, respectively.Conclusion The resistant spectrum of E.coli was wide and serious, gene was polymorphism, and the distribution had a certain timeliness and regional in parts of Shandong Province.

Abstract:Fermented tofu is a type of traditional Chinese food. The aim of this study was to compare the bacterial composition and its effect on the quality and safety of fermented tofu.Methods The total DNA was directly extracted from seven brand of fermented tofu samples produced in four provinces. The V3 region of 16S rRNA gene were amplified, and PCR products were mixed for pyrosequencing. Results According to the analysis of the sequences, Firmicutes, Proteobacteria, Bacteroidetes and Fusobacteria were predominant, accounting for 97.4% of all the bacteria. In terms of genus, most types of the fermented tofu had more than 10 genus members. It was also found that the composition of bacterial communities related to the geographic location and the production processes of fermented tofu. On the other hand, bacterial communities in some of fermented tofu showed relatively high abundance of pathogen or opportunistic pathogen, such as Klebsiella, Salmonella, Cronobacter, Vibrio, Enterobacter and Bacteroidetes.Conclusion These results suggested that the existing fermented tofu production model needed to be updated, and some products might have a risk of food safety.

Abstract:To analyze the epidemiological characteristics of foodborne disease incidents in Zhejiang Province from 2010 to 2012, and provide the prevention and control priorities.Methods Descriptive epidemiological analysis was performed on the incidents reported through the national reporting system for foodborne disease (food poisoning) incidents in Zhejiang from 2010 to 2010.Results A total of 95 foodborne disease incidents were reported in Zhejiang from 2010 to 2012. The majority was caused by microorganism contamination (58.9%), in which Vibrio parahaemolyticus was the most common pathogen (23.2%). Most foodborne disease incidents occurred between May and September (66.1%), and the incidence of foodborne disease incidents caused by microorganism peaked in summer and autumn. For the attributable foods of the foodborne disease incidents, meat and meat products was the most common around the year. Meat and meat products were mainly contaminated by Vibrio parahaemolyticus or non-typhoidal Salmonella. The second common food were aquatic products, which were mainly contaminated by Vibrio parahaemolyticus, especially in the second and third quarter. There were foodborne disease incidents caused by poisonous mushroom and misuse of nitrite.Conclusion It was necessary to improve the food safety management, and the focus were meat and meat products, aquatic products and nitrite. Health education should be conducted about food safety to reducing foodborne disease incidents by poisonous mushroom. Restaurants and canteens were the key places for foodborne disease incidents prevention and control, and Vibrio parahaemolyticus was the major pathogen to which more attention should be paid in foodborne disease incidents prevention and control.

Abstract:To develop a rapid method for determination of zearalenone in grain and its products by liquid chromatography tandem mass spectrometry (LC-MS/MS) and provide analytical methodology for the wheat flour and corn flour in Ningxia.Methods Samples of grain and its products were ultrasonically extracted by acetonitrile-water (84∶16) solution and cleaned up by PriboFast 226 multifunctional clean-up column. Zearalenone was separated on Atlantis T₃ chromatographic column with mobile phase of methanol-10 mmol/L ammonium acetate on gradient elution. The zearalenone was determined and quantified by mass spectrometry. Results The average recoveries of zearalenone in wheat and corn samples at three spiked levels were 85.4%-93.7% with relative standard deviations less than 9.0%. The limit of detection (LOD) and the limit of quantitation (LOQ) were 0.08 and 0.2 μg/kg respectively.Conclusion The method was accurate, reliable, and could be used as a quality control method for zearalenone in grain and its products.

Abstract:To establish a solid phase extraction (SPE)/high-resolution benchtop Q exactive mass spectrometry (HRMS) method for the analysis of morpholine in apples and citrus.Methods The samples were first extracted with 1% formic acid in acetonitrile-water (1∶1, V/V) and then cleaned up using SPE procedure. The chromatographic analysis was performed on a BEH HILIC column with 0.1% formic acid and 4 mmol/L ammonium formate in water/acetonitrile as the mobile phase with gradient elution. The internal standard calibration was used for quantification.Results The linearity was satisfying within 1-100 μg/L, and the coefficients of determination (r²) were above 0.999 for morpholine. The limit of detection (LOD) and the limit of quantitation (LOQ) were 5 and 10 μg/kg, respectively. The recoveries of the spiked apples and citrus samples at the levels of 10,0, and 100 μg/kg ranged from 81.3%-103.7%, with intra-day repeatability and inter-day reproducibility precision 2.7%-7.4% and 1.7%-8.1%, respectively.Conclusion The method was sensitive and accurate, and was suitable for the analysis of morpholine in apples and citrus.

Abstract:To compare the effect of RT-PCR and isolated culture for the detection of food practitioners of Salmonella and Shigella.Methods ① RT-PCR, ② isolated culture. Results The detection rate of RT-PCR was significantly higher than that in isolated culture for food practitioners intestinal Salmonella and Shigella.Conclusion RT-PCR method was superior to the isolation and culture method in the detection of practitioners physical examination of Salmonella and Shigella in terms of detection rate, accuracy and timeliness. Therefore, the use of RT-PCR in the physical examination of employees has very important practical application value.

Abstract:To verify the effect of long-range UV spectrophotometry in detection and identification of oils of different quality.Methods Rapid detection equipment was developed and ultraviolet absorption method was used for the detection. Samples were collected during food safety supervision in Suzhou, including 65 frying oil, 37 hot pot red oil, 3 suspected recycled cooking oil from catering units and 111 gutter oil blind samples. All samples were subjected to rapid detection and analysis, and compared with laboratory test results. Results The method could effectively detect gutter oil, frying oil and hot pot red oil, and the rate of accuracy was up to 79.28% in the blind sample test.Conclusion The instrument could be applied in food safety supervision at the local level for edible oil.

Abstract:To establish an improved solid phase extraction-high performance liquid chromatography method with fluorescence determination for the detection of benzopyrene (BP) in cooking oil.Methods Cooking oil samples were prepared by neutral alumina solid phase extraction (SPE) column. This study investigated the effect of grease removal and recovery of BP as a function of water content in the neutral alumina packing. Neutral alumina packing with 6% water content was found to be the best solid phase extraction packing for BP pre-treatment. In the HPLC method, the HPLC column used was Ultimate XB-C₁₈ (250 mm×4.6 mm, 5 μm) column from Welch Materials, Inc. The mobile phase was acetonitrile-water (88∶12, V/V) with a flow rate of 1.0 ml/min, the column temperature was 30 ℃, and the injection volume was 10 μl.Results The limit of determination was 0.5 ng/g (S/N=3), the linear range was 0.5-100 ng/ml, the recoveries were 91.2%-101.0% and the relative standard deviations were 2.2%-2.9%.Conclusion The method is highly sensitive with good selectivity and accurate quantification, which is suitable for BP determination in cooking oil.

Abstract:To evaluate and validate the performance of the RapidChek SELECT method for rapid detection of Salmonella in foods.Methods The limit of detection (LOD) and the specificity of RapidChek SELECT method were assessed by spiking Salmonella and non-Salmonella reference cultures into different food matrix, respectively. Meanwhile, RapidChek SELECT methodwas validated via examining Salmonella contamination in food samples in comparison with the China national standardmethod. Results The limit of detection of RapidChek SELECT method were 1 cfu/25 g or 1 cfu/ml. The RapidChek SELECT method showed good specificity and no cross-reactivity in determination of 10 kinds of non-Salmonella reference strains. The lowest cell density of Salmonella in food samples for direct detection by RapidChek strip was 10⁶ cfu/ml. Of the 40 food samples examined, 87.5% (35/40) and 85% (34/40) were positive for Salmonella examined by RapidChek SELECT method and China national standardmethod, respectively. A good coincidence in the results obtained by both methods was observed (97.5%, 39/40). RapidChek SELECT method exhibits a slightly better proficiency than China national standardmethod.Conclusion The RapidChek SELECT is an effective alternative analytical method with characteristics of high sensitivity, specificity, easy-to-use, lower interference from non-Salmonella, time-saving, and suitable for rapid detection of Salmonella in foods.

Abstract:To develop a multiplex PCR protocol by which Escherichia coli and Salmonella in raw pork could be simultaneously detected and investigate possible pathogenic bacteria contamination.Methods Primers were designed in accordance with the rfbE gene of Escherichia coli O157∶H7 and invA gene of Salmonella. Through reaction optimization, specificity and sensitivity tests of single gene and multiplex gene PCR, a duplex PCR method was established for rapid detection of Escherichia coli and Salmonella. 144 raw pork samples were collected from different general supermarkets, chilled meat shops and farmer's markets in the city of Zhengzhou, and were analyzed by the PCR method. Conventional microbiological examination was also taken as a control. Results The duplex PCR protocol turned out to be specific, effective with a sensitivity of 10 pg/μl. The examination of the raw pork samples showed that 10 out of 144 were Escherichia coli positive (6.94%), whilst Salmonella was detected among 13 samples (9.03%), and 2 samples were both positive (1.38%).Conclusion A duplex PCR assay was established for the rapid simultaneous detection of Escherichia coli and Salmonella, and pathogenic bacteria contamination existed in raw pork which should be concerned about.

Abstract:Food safety is one of the essential issues of public health in the world. Especially under the impact of globalization, factors influencing food safety are becoming diversified and complicated.In China the increasing number of food safety related incidents has attracted the public attention, and the various reasons in our society make it extremely difficult to be solved. As a new interdisciplinary approach, One Health has been adopted by many countries to settle food safety issues in practice successfully. In this review,new factors arising worldwide which lead to food safety problems was summarized, the meaning of One Health and the development and the practical use of it in other countries was then focuses on, aiming at providing valuable reference to the solution of Chinese food safety issues.

Abstract:To understand the levels and distribution characteristics of heavy metal contamination of vegetables from vegetable base of Guangdong Province.Methods The contamination of heavy metals including mercury(Hg), arsenic (As), lead (Pb), cadmium (Cd) was analyzed according to GB 2762-2012 in 615 vegetable samples from vegetable bases of 21 cities in Guangdong Province. Results The major heavy metal contamination of vegetables in vegetable bases of Guangdong were Pb and Cd. The main vegetable varieties polluted by lead was leafy vegetables, especially lettuce. The main vegetable varieties polluted by cadmium was solanum vegetables, especially eggplant. Vegetables from four areas of Guangdong Province were polluted by lead in different degree, while the highest content of cadmium in vegetables were found in the northern part of Guangdong (Shaoguan) and the western part of Guangdong (Yunfu).Conclusion Overall, the heavy metal contamination of vegetables in vegetable bases was weak. It needs to pay more attention to the lead and cadmium contamination of vegetables in the northern and western part of Guangdong.

Abstract:To investigate organophosphate and carbamate pesticide residues in vegetables daily consumed by local residents in a county of Yunnan Province.Methods In six villages of three townships in a country of Yunnan Province, 424 farmer families were interviewed using a questionnaire and 766 vegetable samples for households use were collected. PR-12N rapid detection instrument was used to detect organophosphate and carbamate pesticide residues. Results 31.18% respondents reported that they used at least one of the prohibited pesticides in the last year. Chlordimeform ranked number followed by methamidophos, carbofuran, omethoate, and fonofos. There were 557 vegetable samples collected from household plots, of which, 34 samples were positive and the positive rate was 6.10%. Among the 51 vegetable samples of field planting, 7 samples were positive and the positive rate was 13.73%. Among the 158 market samples, 20 of them were positive and the positive rate was 12.66%.Conclusion Regulation need to be strengthened and comprehensive measures need to be taken in order to prevent abuse. Most vegetables consumed by local residents were from household plots, vegetables from the markets took certain proportion and the field plantings took the least proportion. All three categories had some positive samples, and the vegetable samples from markets had higher positive rate than from household plots. It was shown that farmers' self protection had limited effect because of the widespread of pesticides in the environment.

Abstract:To investigate the occurrence of lead in liquid milk in China.Methods Lead contents were measured using GFAAS method after digestion and the limit of detection (LOD) was 2.5 μg/kg. 98 samples were collected from 15 provinces of China in 2013. Results The results showed that only 20.4% of the samples contained detectable concentrations of lead ranging from 2.53 to 30.5 μg/kg with a mean level of 2.43 μg/kg, and all below the lead limit (50 μg/kg) of Chinese legislation.Conclusion Lead content in liquid milk in China was generally low, while the 75^th and 95^th percentile amounted up to 40% and 60% of the lead limit, which deserved attention. In order to reduce the lead level in liquid milk, it is necessary to improve the whole process including milk production, storage and sales process.

Abstract:To investigate the glycerol content of 93 domestic wine samples from eight major growing region of China and 4 suspicious poor quality wines and offer important reference for the quality identification.Methods The glycerol content in wines was determined using glycerol enzymatic kits and alcoholic strength was tested according to GB 15038-2006. The results of glycerol content range and the ratio of glycerol/alcohol were analyzed. Results The glycerol content of wine was affected by many factor including climate, grape varieties and grape maturity. The glycerol content ranged from 4-15 g/L and the ratio of glycerol/alcohol ranged from 6%-10% in normal fermentation. Most of the wines were in the normal range. If the results were abnormal, other analysis methods should be taken for further testing. Conclusion The glycerol content combined with the ratio of glycerol/alcohol gave some useful clue of wine quality, and inspection and supervision should be strengthened.

Abstract:Quite a lot of the safety problems of snacks had been reported in China. Compared to their impact on adults, children were more susceptible. It was crucial to carry out the risk monitoring on the snacks, however, due to a large variety of food safety risks and snacks categories, it was hard to perform a complete risk monitoring under the limited budget. Therefore it was important to perform the risk prediction first and establish an risk priority. Methods In this study, the snacks which children consumed frequently in Beijing area were taken as an example, the risk priority of all the snacks/hazard combinations were investigated based on the database of the potential hazards of the snacks related to children during 2011-2013 and consumption behavior of children aged 3-6. The snacks/risks combinations were divided into nine risk matrixes according to risk levels and consumption frequencies. Results The risk prediction results showed that the snacks, including cakes, cookies, candies and chips, which maintained highest consumption frequency and highest level of hazards, belonged to the No.1 risk matrix to be monitored. Conclusion This study provided suggestions for related supervision officials to make their risk monitoring plan on the safety of children's snacks.

Abstract:To find out the contamination status and distribution of pathogenic Vibrios in aquatic products exporting to Macao.Methods A random sampling method were used to collect samples from Zhuhai and Zhongshan. Samples were preliminary screened by multiplex PCR based on HAND system and confirmed by traditional culture and biochemical identification. The contamination status and seasonal, regional and species distribution were finally analyzed. Results Compared with 37.3% coexistent infection rate, the positive rate of Vibrios in aquatic samples was 59.5%. The positive rate of pathogenic Vibrios from May to November was significantly higher than that of January and December. The overall positive rate in Zhuhai district was 69.5%, higher than that in Zhongshan (51.9%) and the difference was statistically significant (P<0.05). The overall positive rate of shellfish was 70.6%, higher than that of fish (54.4%) and the difference was statistically significant (P<0.05).Conclusion The contamination status of pathogenic Vibrios was serious in aquatic products exporting to Macao and needed to monitor to prevent infection.

Abstract:To set up a classification model for health risks for chemicals in food, and provide references for health risk classification and description.Methods Using risk matrix, literature review combined with expert judgment method, key parameters which affected health risk classification were figured out, and indexes which could be used for quantitative evaluation were then decided. Principle of value assignment for classification was established, and health risk classification matrix model was built up for chemicals. Health risk of iodine which has already been assessed was demonstrated as an example to apply the model. Results Two key parameters of classification named as health hazard and possibility and related indexes were built up. According to risk matrix model, three levels of health risk which was high, medium and low were set up. Case study showed that the model was suited for health risk assessment of chemicals in food. Conclusion Health risk classification model was a simple way to conduct risk assessment of chemicals in food. It could be used for scientific classification and quantification, therefore could be beneficial for description of risk classification, and was helpful for food safety risk management and risk communication.

Abstract:To analyze the content of dibutyl phthalate and bis(2-ethylhexyl)phthalate in main food, and assess the risk of dietary exposure of residents in Shibei District.Methods A total of 281 samples were collected from seven food categories and the identification and quantification were performed by GC-MS in selected ion monitoring(SIM) mode. The dibutyl phthalate and bis(2-ethylhexyl)phthalate exposure was estimated by the food consumption data.The health risk was assessed by comparing the dibutyl phthalate and bis(2-ethylhexyl)phthalate exposure with tolerable daily intake (TDI) and the margins of safety (MOS).Results In accordance with the mean value of food consumption estimates, the dibutyl phthalate and bis(2-ethylhexyl)phthalate exposure of Shibei District residents from 7 major food categories were 0.006 899 and 0.005 526 mg/kg BW, and didn't exceed the TDI. The MOS values were 7.2 and 1.8, both above 1.Conclusion In Shibei District, the phthalic acid esters in seven food categories were not intentionally adulterated. The contamination of phthalic acid ester had covered most of the food. The risk was low at present but further study about the long-term exposure was needed.

Abstract:On March 19^th, many people hospitalized after lunch from a canteen of construction site in Shunyi District with symptoms of stomach burning sensation, nausea, vomiting and others. To find out the cause of disease development, control and reduce the disease harm. The emergency response unit of local CDC carried out epidemiological investigation.Methods Descriptive epidemiology, food hygiene survey and laboratory inspection was used to find out the cause, and traceability survey was also conducted. Results Investigation showed that the patients' clinical symptoms were mainly nausea, vomiting, dizziness, stomach burning sensation and the incubation period was 18 minutes, which was consistent with the characteristics of chemicals poisoning. The lunch meal was suspicious and the chefs used white powdery substance as salt to cook the first 5 dishes. Chemical composition of the substance was identified as magnesium silicofluoride and it was the major cause of poisoning.Conclusion The reason of 32 people poisoning was due to misuse of industrial chemicals by the chefs.

Abstract:Staphylococcus aureus is widely distributed in nature and has a strong pathogenicity, and it is considered to be one of the major pathogens causing outbreaks of food poisoning. The pathogenic factor, food contamination status, food poisoning, laboratory diagnosis and preventive measure were described in this paper in order to provide the reference for prevention and control of staphylococcal food poisoning in the future.

Abstract:The most common oligosaccharides in human milk are 3-fucosyllactose (3FL) (0.07-0.86 g/L), lacto-N-tetraose (LNT) (0.18-1.18 g/L), lacto-N-neotetraose (LNnT) (0.10-2.04 g/L), 2′-fucosyllactose (2′FL) (0.45-4.04 g/L), lacto-N-fucopentaose I-III (LNFP I-III), and lacto-N-difucohexaose I-II (LNDFH I-II). They play an important role in infants' growth, which includes enhancing the immunity and regulating microflora in the gut. At present, the main analytical methods for oligosaccharides in human include high performance liquid chromatography (HPLC) and high performance anion exchange chromatography with pulsed electrochemical detection (HPAEC-PED). This paper reviews the content and analytical method of common oligosaccharides in human milk.