Aflatoxin M-1 levels in dairy products from South Korea determined by high performance liquid chromatography with fluorescence detection

Abstract

Sensitive methods for determination of aflatoxin M-1 (AFM(1)) in milk, yoghurt and cheese were developed and evaluated. The analytical methods use high performance liquid chromatography-fluorescence detection after immuno-affinity column purification. The methods showed high linearity (r(2) >= 0.999) for AFM(1) in the range of 0.05-10.00 mu g.l(-1). The limit of quantification for AFM(1) was 0.003 mu g.kg(-1), 0.07 mu g.kg(-1) and 0.05 mu g.kg(-1) in milk, yoghurt and cheese, respectively. The recovery rate of AFM(1) in the dairy products was 83-108% along with 2.1-12.8% repeatability and 0.0-13.1% reproducibility. Levels of AFM(1) were determined in 224 samples of milk, yoghurt and cheese collected from South Korea. The dairy samples were contaminated with AFM(1) in the range of 0.001-0.100 mu g.kg(-1) for milk and 0.015-0.136 mu g.kg(-1) for yoghurt and cheese. The levels of AFM(1) in the dairy products did not exceed the maximum limit (0.5 mu g.kg(-1)) set for milk by Korea Food and Drug Administration.