Occurrence and health risk assessment of AFM1 in commercial yogurt in Thailand

Milk and dairy products, including yogurt, provide essential nutrients and are widely consumed as valuable protein sources. However, considering then increasing prevalence of Aflatoxin B1 (AFB1) in the diet of dairy cows, concerns arise regarding the possible contamination of milk and dairy products with AFM1, the major metabolite of AFB1 excreted in the milk of lactating animals. AFM1, although less potent when compared to AFB1, has been associated with an increase in the prevalence of human hepatic carcinoma. Hence, following a survey on AFM1 contamination of raw and processed drinking milk, this study aimed to evaluate the occurrence of aflatoxin M1 (AFM1) in yogurt available in Bangkok, Thailand, and to estimate the associated dietary exposure and health risk among different population groups. A total of 180 plain yogurt samples were randomly collected from supermarkets during March to June 2024. The samples were extracted using the QuEChERS methodology and analyzed using a validated liquid chromatography- tandem mass spectrometry method. With this method, residual amounts of AFM1 were detected in 12 out of 180 yoghurt samples, with concentrations ranging from 0.031 to 0.048 µg/kg. These levels are below the statutory limits set by the European Union and the FAO/WHO Joint Expert Committee. In addition, a quantitative risk assessment conducted for the AFM1 positive samples revealed that the margin of exposure (MOE) values derived for yogurt were above 10,000. The risk level of hepatocellular carcinoma due to AFM1 exposure expressed as the mean estimated number of liver cancer cases per 100,000 individuals per year ranged from 1.12 × 10^{− 7} to 1.33 × 10^{− 4} for the positive yogurt samples. Although the overall risk of AFM1 exposure is considered low for all age groups, children remain the most vulnerable population; therefore, continuous monitoring of dairy milk and milk products is warranted to minimize potential exposure.