Aflatoxin M1 in Pasteurized Market Milk in Korea

Aflatoxin M1, ingested as aflatoxin B1 via contaminated feedstuff and later converted into, is a major problematic target for milk safety control among the aflatoxin class. Korean government has controlled level of AFM1 in milk at 500 ppt as maximum residue level (MRL), and more recently, government also publicized the proposal for more strict control on fungal toxins about infant and baby foods. In this study the levels of Aflatoxin M1 (AFM1) of 42 marketed milk samples were determined with Enzyme-Linked Immunosorbent Assay (ELISA) to evaluate the status on the contamination of Aflatoxin M1. The evaluated ELISA performances of limit of detection (LOD) and the half maximal inhibitory concentration ($IC_{50}$) were 5 pg/mL (ppt) and 49 ppt, respectively. In all 42 samples, AFM1 appeared above the 5 ppt, with the average of 21 ppt and the range of up to 90 ppt. Only 3 (7%) of samples showed the level of contamination above the EU MRL (50 ppt). Although there was incidence of higher level of contamination compared with previous reports, the result of this study requires more intensive study to control of AFM1 in milk and infant foods.