Research On Sampling Methods In Risk Assessment For Aflatoxins In Peanuts

Peanut as an important oil crops and export advantage crops in China, has an important status in the development of agriculture and export trade. Aflatoxins are predominantly produced by Aspergillus flavus and Aspergillus parasiticus and due to naturally occurring and powerful mutagenic, carcinogenic, teratogenic, immunotoxic to human and animal health that have been classified to be group I carcinogen by the International Agency for Research on Cancer. Currently, the most of international organization, developed countries and developing countries had been setting up severe standard of aflatoxins permitted limits in peanuts and peanut products for ensuring the consumption safety. Recent years, European Rapid Alert System for Food and Feed(RASFF) had been notified about several hundreds batches peanut from China due to aflatoxins exceeds the permitted limits about one fifth in all notifications. Due to aflatoxins contamination in peanuts, industry development of peanut has faced great threat and peanut exporting has faced green trade barriers. In order to fully understand the situation of aflatoxins contamination in the post-harvest peanut in China and guarantee consume safety, we carried out several years of risk assessment for aflatoxins in peanuts. As we know China is a vast country, encompassing 35 latitudes from south to north, the peanuts are planted widely in China. In addition, different latitudes experience various climates and the different regions have different agricultural measures. We know the contamination level of aflatoxins in peanuts correlates with the cliamte factor. By what means can we use sampling to reflect, to the largest extent the contamination level of aflatoxins in peanut. So the sampling methods is very important factor to assure the reliability of sample data. Therefore, we carry out the research on Sampling methods in Risk assessment for aflatoxins in Peanuts have great significance for monitoring and control of peanuts aflatoxins in China.Based on the 7964 survey and assessment data of aflatoxins in national postharvest peanut of five consecutive years from 2009 to 2013, this study established the sampling method suitable for domestic aflatoxins contamination research in peanut and determined the capacity of representative samples on the foundation of aflatoxins contamination in peanut levels by analyzing pollution characteristics, peanut aflatoxins contamination distribution among different areas and different sampling method. The main results are as follows:1. Peanut aflatoxins contamination characteristics were analyzed. Based on the 7964 sample test results and assessment data of aflatoxins in national post-harvest peanuts of five consecutive years in 2009 to 2013, aflatoxins contamination characteristics of post-harvest peanuts were studied using analysis of variance. The aflatoxins contamination data is left-skewed distribution. The differences of inter-province and inter-county are significant. Among all the 63 counties, the difference of eighty percent of all the counties was not significant in the annual, but twenty percent was.2. The relationships between mean and standard deviation, mean and coefficient of variation of aflatoxin B1 in postpartum peanut samples were Studied in our country, and were compared to the related research of international studies. According to the results in this experiment, 7964 data as an object for research, sample mean of aflatoxin B1 in peanut is dominant positively correlated to the sample standard deviation with a correlation coefficient R = 0.984; And the variation coefficient isnegatively related to the sample mean of aflatoxin B1 in peanut with a correlation coefficient R = 0.904.The experiment results showed that the rule in this experiment is in line with international standards.3. The optimal provincial sampling plan of post-harvest peanut is discussed. When sampling in the unit of province, multistage sampling method should be adopted, the sampling frame is county(city):- sample villages and farmers. Taking Anhui Province as an example, the optimal scheme is 10 peanut producing counties, 6 villages from each county(city) and 1 sample from each village randomly selected considering the sampling precision and sampling cost.