Detection and levels of aflatoxin M₁ in raw milk of dairy cows from selected small scale and commercial farms in Harare, Zimbabwe

Abstract

The aim of this study was to determine the presence and concentration levels of aflatoxin M₁ (AFM₁) in raw milk from commercial and small-scale dairy farms in Harare, Zimbabwe. The screening for AFM₁ was performed using the High Performance Liquid Chromatography (HPLC) and the limit of detection was 0.05μg/kg, this is the acceptable limit for aflatoxins in milk as set by the EU so any sample is considered positive if above this limit. Overall, 79.2% (38/48) of the samples were positive, with the commercial sector recording a higher percentage (92.1%, 35/38) of positive samples compared to the small scale sector (30.0%, 3/10). The overall mean concentration of AFM₁ levels for positive samples from the commercial sector was 1.9 and there was a significant difference (p < 0.003) in mean concentration levels between the two commercial farms. In contrast the mean concentration level for the small-scale was 0.9. The mean concentration levels of AFM₁ for commercial farm 1, commercial farm 2 and the small-scale sector were 46, 26 and 38 times above the limit, respectively. The results of the study showed the presence of aflatoxin M₁ in raw milk from commercial and small-scale dairy farms. Aflatoxin M₁ concentration levels in the sampled raw milk could have negative impacts on public and animal health. Hence, further studies are required to ascertain the extent of the problem and the factors associated with high aflatoxin M₁ levels in raw milk in the studied areas.

Keywords: Aflatoxin M₁