Investigation of Farm Gate Cow Milk for Aflatoxin M1

Importance of cow milk in human, especially in infant nutrition, is well known. Nevertheless, contamination of milk with aflatoxins is considered as a potential risk for human health. The aim of this study was to determine the levels of aflatoxin M₁ (AFM₁), metabolite of aflatoxin B1 in raw cow milk in high milk producing areas in Sri Lanka. Aflatoxin M₁ levels were investigated by high performance liquid chromatography (HPLC) equipped with a fluorescence detector, monitoring at wave lengths 365 nm and 425 nm for excitation and emission, respectively. Eighty seven samples of raw milk were collected from randomly selected dairies in seven provinces in the country, and analyzed for AFM₁ using the Official Methods of Analysis of Association of Official Analytical Chemists (AOAC) International. The percentage recovery of AFM₁ was 85.2 ± 4.03 with respect to an artificially contaminated concentration of 48.6 ng/L. AFM₁ was detected in 33% of locally manufactured raw milk samples in concentrations ranging from 13.1 ng/L to 84.5 ng/L with a mean level of 40.2 ng/L. Percentage of contaminated samples (9.2%) exceeded the European Communities/Codex Alimentarius recommended limit of 50 ng/L. None of the milk samples from Western, Uva & Sothern provinces were contaminated at a detectable level of AFM₁. The results suggest a need to introduce safety measures for AFM₁ levels in liquid milk in local market under Prevention of Food Adulteration Act of Sri Lanka as well as to prescribe a limit of aflatoxin AFB₁ level in dairy cattle feedstuffs in order to minimize the health hazard risk in Sri Lanka.

DOI: 10.4038/tar.v21i2.2593

Tropical Agricultural Research Vol. 21(2): 119-125 (2009)