Assessment of soil quality in an arid and barren mountainous of Shandong province, China.

Forest soils are important components of forest ecosystems, and soil quality assessment as a decision-making tool to understand forest soil quality and maintain soil productivity is essential. Various methods of soil quality assessment have been developed, which have occasionally generated inconsistent assessment results between soil types. We assessed the soil quality of five communities (herb, shrub, Quercus acutissima, Pinus thunbergii, and Q. acutissima-P. thunbergii mixed plantation) using two common methods of dry and barren mountains in the Yimeng Mountain area, China. Sixteen soil physical, chemical and biological properties were analysed. The soil quality index was determined using the established minimum data set based on the selection results of principal component analysis and Pearson analysis. Silt, soil total phosphorus (P), soil total nitrogen (N), L-leucine aminopeptidase, acid phosphatase and vector length were identified as the most representative indicators for the minimum data set. Linear regression analysis showed that the minimum data set can adequately represent the total data set to quantify the impact of different communities on soil quality (P < 0.001). The results of linear and non-linear methods of soil quality assessment showed that the higher soil quality index was Pinus forest (0.59 and 0.54), and the soil quality index of mixed plantation (0.41 and 0.45) was lower, which was similar to the herb community (0.37 and 0.44). Soil quality was mostly affected by soil chemical properties and extracellular enzyme activities of different communities, and the different reasons for the low soil quality of mixed plantations were affected by soil organic carbon (C) and total C. Overall, we demonstrate that the soil quality index based on the minimum data set method could be a useful tool to indicate the soil quality of forest systems. Mixed plantations can improve soil quality by increasing soil C, which is crucial in ecosystem balance.

Transcriptome profiling based on larvae at different time points after hatching provides a core set of gene resource for understanding the immune response mechanisms of the egg-protecting behavior against Vibrio anguillarum infection in Amphioctopus fangsiao.

Mollusks have recently received increasing attention because of their unique immune systems. Mollusks such as Amphioctopus fangsiao are economically important cephalopods, and the effects of their egg-protecting behavior on the larval immune response are unclear. Meanwhile, little research has been done on the resistance response of cephalopod larvae infected with pathogenic bacteria such as Vibrio anguillarum. In this study, V. anguillarum was used to infect the primary hatching A. fangsiao larvae under different egg-protecting behaviors for 24 h, and a total of 7156 differentially expressed genes (DEGs) were identified at four time points after hatching based on transcriptome analysis. GO and KEGG enrichment analyses showed that multiple immune-related GO terms and KEGG signaling pathways were enriched. Protein-protein interaction networks (PPI networks) were used to search functional relationships between immune-related DEGs. Finally, 20 hub genes related to multiple gene functions or involved in multiple signaling pathways were identified, and their accuracy was verified using quantitative RT-PCR. PPI networks were first used to study the effects A. fangsiao larvae after infection with V. anguillarum under different egg-protecting behaviors. The results provide significant genetic resources for exploring invertebrate larval immune processes. The data lays a foundation for further study the immune response mechanisms for invertebrates after infection.

[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.

[Cost-benefit analysis in setting up limitation standards of aflatoxins in foods].

OBJECTIVE: To explore a reasonable limitation standard for aflatoxins in foods to protect the health of people in China with a cost-benefit analysis. METHODS: A traditional mathematical model and MOE (margin of exposure) method was used to assess the effect of different limiting standards on health for total aflatoxins and aflatoxin B1 in peanut, corn and rice, and the loss of foods under different limiting standard levels was also calculated. RESULTS: The change of limiting standards for total aflatoxins and aflatoxin B1 in peanut and corn might have no significant influence on reducing the prevalence of liver cancer in China, but the loss of foods was significantly different. The change of limiting standards for total aflatoxins and aflatoxin B1 in ice might have significant influence both on reducing liver cancer and losing foods. CONCLUSION: The following limiting standards is advisable: 20 microg/kg for total aflatoxins and 15 microg/kg for Aflatoxin B1 in peanut and its products, 20 microg/kg for total aflatoxins and 15 microg/kg for aflatoxin B1 in corn, 10 microg/kg for total aflatoxins and 5 microg/kg or 10 microg/kg for aflatoxin B1 in rice.

[Application of risk assessment in process of standards establishment about campylobacter jejuni in chicken].

OBJECTIVE: According to risk assessment results of the Campylobacter jejuni in chicken of Chinese residents' dietary, from the point of the standard management, establish the feasible measures to reduce the risk. METHODS: Half-quantity risk assessment of Risk Ranger was used. RESULTS: Campylobacter jejuni usually could not reproduce in the processing environment or in the processed products of chicken. Currently, the risk of the likelihood that the urban people of our country have Campylobacter jejuni infections due to eating chicken was six times as that of the rural people. CONCLUSION: There is no need to set a limit level for Campylobacter jejuni in the standard of chicken products. Control in the feeding, processing and preparation before eating of chicken are the important measures in reducing the Campylobacter jejuni infections caused by chicken.

[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.