Evaluation of the extraction methods for aflatoxin M1 (AFM1) in yoghurt for HPLC technique

V. Kadigama, K.E. Aidoo, A.G. Williams & A.A.G. Candlish

Author address: 

Dept of Biological & Biomedical Sciences, School of Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA


The mould, Aspergillus parasiticus produce 4 toxic metabolites, AFB1, AFB2, AFG1 and AFG2. AFB1 which may be present in animal feedstuff appears as aflatoxin M1 (AFM1), a genotoxic carcinogen, in milk and milk products. This paper presents an evaluation of AFM1 extraction methods from yoghurt prior to immunoaffinity column procedure. Three AFM1 extraction methods were employed and low fat natural yoghurt was used for the study. In the first method, yoghurt was contaminated with 0ng/ml, 5ng/ml, 10ng/ml and 12ng/ml and AFM1 was purified using methanol:water (60:40 v/v). In the second method, concentrations of AFM1 were 0ng/ml, 5ng/ml and 10ng/ml. AFM1 was extracted using dichloromethane and diatomacious earth following washing with n-hexane. Concentrations of AFM1 used were 0ng/ml, 5ng/ml, 10ng/ml and 20ng/ml in the third method. Methanol:water (80:20 v/v) was mixed with AFM1 contaminated yoghurt and centrifuged to obtain the supernatant. The extractions were analysed using High Performance Liquid Chromatography (HPLC). Recovery rates obtained by the first method ranged approximately between 28% and 38% while with the second method recoveries were between 10% and 26%. Recoveries using the third method were between 75% and 93%, and therefore, the third method is recommended for extraction of AFM1 from yoghurt.

abstract No: 

FdBev 06

Full conference title: 

161st Society for General Microbiology
    • SGM 161st (2007)