Contamination And Seasonal Variation Of Aflatoxins In Feed And Milk And In Gansu Province

Aflatoxins(AFs)in milk pose a great threat to human health.The presence of AFs in milk is closely related to the contamination of aflatoxin in feed.In this study,to understand the content of aflatoxin B1(AFB1)in feed and milk,as well as the seasonal varation of aflatoxin M1(AFM1)in milk,seven kinds of feed samples(332 in total numers)and 252 raw milk samples were collected in spring,summer,autumn and winter from different areas of Gansu Province in 2015.The concentration of AFB1 in the feed were tested by enzyme linked immunosorbent assay method.The concentration of AFM1 in the milk samples were determined by high performance liquid chromatography method.The main results obtained are as follows:1.180(55.72%)out of 337 feed samples were found to be AFB1-containminated.The average content of AFB1 was 1.38 ?g·kg-1.The content of AFB1 was different in different kinds of feeds.The level of AFB1 in silage(4.53 ?g·kg-1)was significantly higher than that in other feed.AFB1 was under the detection limit in dried alfalfa samples.Overall,the level of AFB1 contamination in green forage was lower than that in concentrated feed.The content of AFB1 in all samples was lower than the national standard for all kinds of feed,and only few samples exceeded the European Union Standard.2.AFM1 was found in 126(50%)out of 252 raw milk samples.The average content of AFM1 in the four seasons milk was 4.18 ng·L-1 and the content of AFM1 in the containminated samples was lower than the national limit standard(500 ng·kg-1).Three samples(1.19%)exceeded the European Union Standard(50 ng·kg-1).The pollution level of AFM1 in milk in Gansu Province showed a seasonal variation.The content of AFM1 in milk was the highest in autumn and the lowest in summer,which were significantly different from the other seasons.3.The average content of AFM1 in milk produced by scale factories was 3.41 ng·L-1,and that was 4.79 ng·L-1 in milk produced by farmers.The results indicated that,on the whole,the contamination level of AFM1 in milk produced by scale factory was lower than that of retail farmers.The main conclusions drawn from this study were as follows: The contamination level of AFs in feed and milk in Gansu Province was low,which meets the national standards.However,there were still few feeds and milk samples with aflatoxin levels exceeding the European UnionStandard.The contamination of AFM1 in milk showed a seasonal dynamic change,which was mainly related to the differen feed formula and pollution situation of AFB1 in feed in different seasons.Therefore,lowering the content of AFB1 in feed was the most effective way to reduce the contamination of AFM1 in milk.Compared with retail farmers,milk produced by scale factories was more qualified with safety standards.Retail farmers can take various measures to control the content of AFM1 in milk.These conclusions can provide the theoretical basis in the production practice for producers,and provide useful information for consumers,as well as ensure the security of food production and consumption in China.