[Quantitative risk assessment of Listeria monocytogenes in bulk cooked meat products].

OBJECTIVE: To conduct a quantitative risk assessment for Listeria monocytogenes in bulk cooked meat products in China. METHODS: The data on the contamination level of Listeria monocytogenes in cooked meat products was from national foodborne disease surveillance network, involving a total of 841 samples. All the samples were detected by a qualitative method and 97 samples among them were detected using a quantitative method. The intake data of cooked meats was from Chinese National Nutrition and Health Survey in 2002 and population data in the monitoring sites was collected from National Bureau of Statistics in 2008 to estimate the composition of the population of different ages, which would be the base of assessing the probability of listeriosis in the different subpopulations. Using @Risk software to estimate the risk of listeriosis caused by consuming deli meats for different subpopulation (0 - 4 years old, 5 - 64 years old and 65 years and older) by quantitative risk assessments which involved hazard identification, hazard characterization, exposure assessment and risk characterization and conduct sensitivity analysis. RESULTS: The contamination level of Listeria monocytogenes in the most of samples (96.08%, 808/841) was less than 3 MPN/g (0.5 lg MPN/g), and the average concentration of Listeria monocytogenes was -0.61 lg CFU/g (90%CI: -1.22 - 0.46 lg CFU/g). Estimated servings of cooked meat consumption for 0 - 4, 5 - 64 and 65 years and older were 5.52 × 10(9), 8.99 × 10(10), 1.01 × 10(10), respectively. Estimated number of cases (median) of listeriosis each year per million people caused by consuming cooked meats in young (0 - 4 years old), intermediate age (5 - 64 years old) and elderly (65 years and older) population were 5.53 × 10(-3), 1.72 × 10(-4), 7.57 × 10(-3), respectively. Results of sensitivity analysis showed that contamination level at retail, serving size of cooked meats, storage time at home, storage temperature and ERG at 5°C were positive factors for the risk of listeriosis (r value was 0.607, 0.408, 0.339, 0.259, 0.183 respectively, P < 0.05). CONCLUSION: Cooked meat products in bulk is a risk food, which could cause listeriosis. Contamination level of Listeria monocytogenes in cooked meat products in bulk is the top risk factor for the listeriosis.

[Exposure assessment of liver cancer attributed to dietary aflatoxins exposure in Chinese residents].

OBJECTIVE: To evaluate the risk of liver cancer attributed to dietary aflatoxins exposure in Chinese residents. METHODS: Mathematics model and "Margin of Exposure (MOE)" methods were employed in this study. The data used in mathematics model came from Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the detection results of hepatitis B virus ( HBV) indicator in Chinese residents' blood sample in 2004. The data used in MOE model came from animal experiments, the fourth nutrition and health investigation among Chinese residents, and national inspection network for food contaminations. RESULTS: Mathematics model indicated that for those people who were exposed to aflatoxins at average level (665.43 ng/d), the liver cancer incidence rate resulting from aflatoxins exposure was 0.4033 per 100 thousand person years. For those people who were exposed to aflatoxins at a high level (97.5 percentile, 24 787.20 ng/d) the liver cancer incidence rate attributed to aflatoxins exposure was 15.0215 per 100 thousand person years. Results from the MOE method showed that for the people in whole country, urban and rural areas who were exposed to aflatoxins at average level (0.011 09, 0.008 13 and 0.012 49 microg x kg(-1) x d(-1) respectively), the MOE values for aflatoxins to cause liver cancer were 9017.1, 12 304.7 and 8006.4 respectively. For those people who were exposed to aflatoxins at a high level (97.5 percentile, 0.413 10, 0.289 30 and 0.489 50 microg x kg(-1) x d(-1) respectively), the MOE values for aflatoxins to cause liver cancer were 242.1, 345.7 and 204.3 for whole country, urban and rural areas, respectively. CONCLUSION: For the people whose dietary aflatoxins exposure at average level, the risk of liver cancer attributed to aflatoxins is middle. For the people whose dietary aflatoxins exposure at high level, this kind of risk should be high.

[Risk assessment of Listeria monocytogenes in deli meats and vegetable salads].

OBJECTIVE: To analysis risk from Listeria monocytogenes in deli meats and vegetable salads. METHODS: Use Risk Ranger which is a software programme developed by the University of Hobart, Australia and answer 11 questions on affecting the risk from hazards in the specific foods by combining data from national foodborne diseases surveillance network and some references to make semi-quantitative risk assessment for the specific food. RESULTS: Relative risk from Listeria monocytogenes in deli meats and vegetable salads is 61 and 52, respectively. Incidence of listeriosis caused by deli meats-Listeria monocytogenes pairs and vegetable salads-Listeria monocytogenes pairs is 5.4 and 0.2 cases per million people, respectively. Risk from the former is 32 times than that from the latter. By changing the selection for some risk factors in the model, it was known that the risks from two food-hazard combinations could decrease 10 times, if taking necessary actions after processing. CONCLUSION: Deli meats is a kind of high risk food for listeriosis.

[Quantitative microbiological risk assessment of Salmonella spp. in connmmon catering foods].

OBJECTIVE: To study the relationship between foodborne diseases (FBD) and contamination of Salmonella spp. in catering foods, quantitative microbiological risk assessment (QMRA) of Salmonella spp. was used to evaluate the food material or the ready to eat food. METHODS: The contamination data of Salmonella spp. in 10 896 food samples of 9 categories of food which were collected by National Food Contamination and Food Borne Disease Surveillance Net, combining with diet consumption data from National Food Nutrition Survey in 2002, were analyzed by the microbiological risk assessment model developed by WHO/FAO or FDA/FSIS of US to predict probability of FBD. RESULTS: The results of MRA showed that the probability of salmonellosis by consuming ready to eat meat in summer and autumn was 0.20, much higher than the other foods. Although the contamination level in raw poultry was higher than meat, the probability of salmonellosis by raw poultry (9.11 x 10(-6)) was lower than meat (3.14 x 10(-5)) because of the low consumption volume. CONCLUSION: Probability of FBD was significantly correlated with the volume of food consumption, the status of economy and bacteria contamination level. The level of FBD in summer season was higher than in winter and spring because of ambient temperature.

[Assessment of the BALB/c mice as a suitable animal model for the investigation of food allergy].

OBJECTIVE: This study was to develop a suitable model for the investigation for food allergy. METHODS: BALB/c mice were dosed by intraperitoneally with Ovalbumin, Beef serum albumin, Trypsin inhibitor and Potato acid phosphatase respectively (0.25ml 20mg/mnl) on day 0 and again on day 7. Control group was dosed with PBS. Sera form individual animals were analysed for specific IgE and Passive cutaneous anaphylaxis tests. Additionally, the level of histamine in plasma were detected. RESULTS: The high titres of specific IgE (1: 32) could be provoked in test groups compared with control group. In addition, the level of histamine in plasma of test groups was higher than that in the control group. But there was no statistical significance between group food allergen and group Potato acid phosphatase. CONCLUSION: Although allergic action of BALB/c mice could be provoked, the situation of the allergic action of BALB/c mice to the proteins was very different with the human being. The BALB/c mice could not be a suitable model for the investigation for food allergy.