Detection of aflatoxin M1 in milk, cheese and sour cream samples from Costa Rica using enzyme-assisted extraction and HPLC
2015
Chavarría, Guadalupe | Granados-Chinchilla, Fabio | Alfaro-Cascante, Margarita | Molina, Andrea
Aflatoxins are toxic fungal metabolites, which can be found in feed. Aflatoxin M ₁ (AFM ₁) is excreted into milk when ruminants ingest aflatoxin B ₁ contaminated feedstuffs. Due to its carcinogenic potential, contamination of milk and dairy products with AFM ₁ may pose a risk for consumers. Hence, it is considered a public health concern. In this survey, the level of AFM ₁ contamination of dairy products marketed in Costa Rica was determined by enzyme-assisted extraction, immunoaffinity clean-up and high-performance liquid chromatography coupled with a fluorescent detector (HPLC-FLD) in fluid milk (n = 70), fresh cheese (n = 70) and sour cream (n = 70) collected at local convenience stores and supermarkets. AFM ₁ concentrations in milk and fresh cheese ranged from 19 to 629 ng/L and from 31 to 276 ng/L, with mean values of 136 ng/L and 74 ng/L, respectively, whereas none of the sour cream samples analysed tested positive for this aflatoxin. In 30 milk samples, and 10 cheese samples, AFM ₁ concentrations surpassed threshold concentrations as established by the European Commission. Thus, sour cream and – to a lesser extent – cheese manufacturing seems to reduce the amount of AFM ₁ present in milk, possibly due to fraction redistribution or microbiological degradation. The survey results reveal improper quality control procedures in the Costa Rican dairy industry. Therefore, a surveillance programme for dairy products in our country is recommended.
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