Introduction: Aflatoxin M₁ is an important mycotoxin frequently found in milk and dairy products. The main objective of this work was to study the stability of AFM₁ during production and refrigerated storage of probiotic yogurt.

Materials and methods: Two kinds of probiotic yogurt were made by cow’s milk artificially contaminated with aflatoxin M₁ at a level of 100 ng/l, and fermented to reach pH 4.5. The yogurts were stored at 4 °C for up to 21 days. Analysis of aflatoxin M₁ in yogurt was carried out, using immunoaffinity column extraction and liquid chromatography coupled with fluorometric detection.

Results: The aflatoxin M₁ levels in the probiotic yogurts showed a significant decrease (p<0.05) compared with those initially added to milk. During the refrigerated storage the aflatoxin M₁ was lower in‘DELVO-YOG MY 1821’(MY 1821) yogurt than ‘FD-DVS ABY3’ (ABY3), but the difference was not significant (p>0.05). The percentage loss of the initial amount of aflatoxin M₁ in milk was estimated at about 41% and 49% by the end of storage for yogurts made by ABY3 and MY1821 yogurt, respectively. Loss of viability of the probiotic bacteria in presence of aflatoxin M₁ was strain dependent. Aflatoxin M₁ had no remarkable effect on viability of tested bacteria.

Conclusion: The probiotic yogurt can reduce the AFM₁ content of initial milk during production and storage. More studies are needed to investigate the effectiveness of other mixed probiotic cultures with different composition, to reduce the AFM₁ content of milk.