| ObjectThe positive rate and content background of deoxynivalenol(DON)in the national(continental)grain food samples were tested,and the pollution status was analyzed and its spatial distribution characteristics were preliminarily discussed to provide a technical way to reduce DON pollution.MethodSampling area: According to the national(mainland)administrative division,from June 2017 to June 2018,grain samples of 29 provinces were collected,including(Heilongjiang,Jilin,Liaoning,Beijing,Tianjin,Hebei,Henan,Shanxi,Shanxi,Shandong,Jiangsu,Sichuan,Yunnan,Chongqing,Guangdong,Guangxi,Hunan,Hubei,Fujian,Shanghai,Anhui,Zhejiang,Guizhou,Jiangxi,Ningxia,Inner Mongolia,Tibet,Xinjiang,Gansu).Sampling type: Collect local staple food grains and other kinds of grain samples.The staple foods include wheat and flour,corn,rice and barley in Tibet.Other types include soybeans,black rice,mung beans,millet,red beans,and glutinous rice.Sampling method and sample storage: Collect food samples from commercial and household households,and store them in sterilized kraft paper envelopes.After sampling,the samples are dried and stored in a desiccator and tested as soon as possible.Number of samples collected: 2790 samples were collected from 11 samples,including 591 flour,541 corn,614 rice,278 soybeans,231 green beans,200 millet,34 green barley,136 red beans,58 wheat,45 glutinous rice.Detection and analysis method: The DON content in grain was determined by enzyme-linked immunosorbent assay.Result1.Analysis of total pollution status of cereal DONThe detection rate from high to low was 87.1% for black rice,83.1% for soybean,76.3% for flour,76.5% for barley,73.5% for millet,73.5% for red beans,69.5% for corn,64.1% for mung bean,44.8% for wheat,44.3% for rice,and glutinous rice was 31.1%,the difference was statistically significant(P<0.05).The average content of DON in each group was 141.0μg/kg of flour,139.7μg/kg of black rice,125.7μg/kg of soybean,123.4μg/kg of corn,115.0μg/kg of red bean,110.4μg/kg of millet,108.8μg/kg of green barley,107.5μg/kg of mung bean,97.9μg/kg of wheat,95.7μg/kg of rice,and 87.3μg/kg of glutinous rice.The difference was statistically significant(P<0.05).There were 51 samples exceeding the standard,and the over-standard rate was 1.8%.Only the corn and flour were over-standard,which was 5.4% for corn and 3.9% for flour.Analysis of DON pollution in wheat and flour:The detection rate,the detection rate of flour was 76.3%,and the detection rate of wheat was 44.8%.The difference was statistically significant(P<0.05).The average level of DON pollution in flour was 141.0 μg/kg,and that in wheat was 97.9 μg/kg.The difference was statistically significant(P<0.05).For the over-standard condition,no over-sample was found in wheat,and the DON exceeding rate in flour was 3.9%.And the maximum amount of flour is about 5 times that of wheat.The pollution of DON in corn,flour,black rice and soybean was more serious than other groups,the pollution level was relatively high,and the pollution of rice,glutinous rice and wheat was light.2.Regional distribution of DON toxins in cerealsThe detection rates in all regions were 74.4% in North China,70.3% in Northeast China,69.6% in Central China,69.4% in Southwest China,67.1% in South China,64.3%in East China,and 55.3% in Northwest China.The difference was statistically significant(P<0.05).The average ranks of the regions were 1528.5 in North China,1494.6 in Southwest China,1455.3 in Northeast China,1393.8 in Central China,1390.3 in East China,1278.8in South China,and 1260.7 in Northwest China.The difference was statistically significant(P<0.05).The pollution of DON in North China regions of the seven geographical is serious,and the pollution in the northwest is the lightest.3.Impact of climate type factors on DON productionFlour: The detection rate was 69.2% in the temperate monsoon climate zone,86.0% in the subtropical monsoon climate zone,86.2% in the temperate continental climate zone,and 20.0% in the plateau alpine climate zone.The subtropical monsoon climate zone was found to be higher than the temperate monsoon climate zone and the plateau alpine climate zone.(P<0.05).The average pollution level was 177.7μg/kg in the subtropical monsoon climate zone,169.7μg/kg in the temperate continental climate zone,126.3μg/kg in the temperate monsoon climate zone,and 96.4μg/kg in the plateau alpine climate zone.The difference was statistically significant.(P<0.05).In general,the DON pollution of the subtropical monsoon climate zone is the most serious,and the flour pollution in the plateau alpine climate zone is relatively light.Corn: The detection rates of subtropical monsoon climate zone,temperate monsoon climate zone and temperate continental climate zone were 85.5%,74.5% and 43.5%,respectively,and the difference was statistically significant(P<0.05).The average pollution level was 136.9μg/kg in the subtropical monsoon climate zone,130.0μg/kg in the temperate monsoon climate zone,and 92.3μg/kg in the temperate continental climate zone.The difference was statistically significant(P<0.05).The over-standard rate was 8.9%,4.9%,and 3.1%.On the whole,the pollution in the temperate continental climate region is relatively light,and the pollution in the subtropical monsoon climate region is heavier.Rice: The detection rate.The subtropical monsoon climate zone,temperate monsoon climate zone and temperate continental climate zone were 56.0%,38.3%,and 13.6%,respectively,and the difference was statistically significant(P<0.05).The average pollution level was 103.2μg/kg in the subtropical monsoon climate zone,90.7μg/kg in the temperate monsoon climate zone and 88.7μg/kg in the temperate continental climate zone,the difference was statistically significant(P<0.05).There is only one rice in Jiangxi exceeding the standard.In general,the pollution of rice DON is in the subtropical monsoon climate zone > temperate monsoon climate zone > temperate continental climate zone.The three cereal grains tested this time showed significantly higher DON pollution in the subtropical monsoon climate zone than in other regions.4.DON pollution in monsoon and non-monsoon areasFlour: The average pollution level was 142.0 μg/kg in the monsoon region and 133.3μg/kg in the non-monsoon region.Exceeding the standard,the non-monsoon area did not detect excessive samples,and the monsoon area exceeded the standard rate of 3.7%.Corn: The detection rate of maize DON in monsoon and non-monsoon areas was76.9% and 20.0%,respectively,and the difference was statistically significant(P<0.05).The average pollution level was 126.9μg/kg in the monsoon region and 77.5μg/kg in the non-monsoon region,the difference was statistically significant(P<0.05).The over-standard rate was 5.5% and 2.9%,respectively.It can be seen that the DON pollution in the monsoon region is more serious than that in the non-monsoon region.Rice: The detection rate of rice DON in the monsoon region was higher than that in the non-monsoon region(P<0.05),which was 45.2% and 23.1%,respectively.Only one sample exceeding the standard was located in the monsoon region.It can be seen that rice pollution in the monsoon region is more common.The DON pollution of the three main imported grain and grain crops showed a higher monsoon zone than the non-monsoon zone.5.DON pollution at different altitudesFlour: The detection rate was 20.0% for the first step,82.7% for the second step,and71.9% for the third step.The difference was statistically significant(P<0.05).Rice: Contamination,the detection rate was 31.9% for the second step and 53.1% for the third step,the difference was statistically significant(P<0.05).Conclusion1.Species analysis: The DON pollution of 11 kinds of grain foods tested this time has been reduced compared with previous reports,and the quality of food hygiene has improved.Among them,the over-standard conditions of corn and flour are more serious,and the pollution level is also higher.The detection rate of black rice and soybeans is higher,indicating that pollution is more common,while the pollution of wheat,rice and glutinous rice is relatively light.In addition,the detection of flour DON contamination is significantly higher than that of wheat.We speculate that the cause of serious DON contamination may be related to the processing methods and storage conditions of wheat.2.Regional distribution: Among the seven geographical divisions in China(North China,East China,Central China,South China,Northeast China,Southwest China,Northwest China),the pollution of DON in North China is the most serious,and the pollution in Northwest China is the lightest.3.DON influencing factors: The DON pollution of the three staple foods(corn,flour,rice)was analyzed.The results showed that the 0°C isotherm was more serious in the south than in the north,and the monsoon region(wet region)was more serious than the non-monsoon region(arid region).However,the trend of the three-level ladder distribution is not obvious.The difference of DON pollution rate and content in different geographical areas reflects the toxigenic characteristics of Fusarium: the production of DON toxin is closely related to meteorological climate,in which temperature and humidity are important factors,and altitude(oxygen partial pressure)is the secondary influence factors.This distribution also suggests that the regional high incidence of certain diseases in humans and animals may be related to the regional distribution of mycotoxins.4.DON toxin in food may be a risk factor for chronic diseases such as osteoarthritis and esophageal cancer. |
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