Prevalence and concentration of aflatoxin M1 in milk and dairy products: an umbrella review of meta-analyses.

BACKGROUND

Aflatoxin M1 (AFM1) is a derivative of aflatoxin B1 and a significant contaminant of milk and dairy products. In this study, we implemented an umbrella review of all existing systematic reviews and meta-analyzing studies to apprise and summarize the worldwide prevalence and level of AFM1 in milk and dairy products.

METHODS

We conducted a systematic review of structured review and meta-analysis articles published in English until January 2024, with no time limit. Articles were sourced from reputable databases, including PubMed/MEDLINE, EMBASE, Scopus, Web of Science, CINAHL and the Cochrane Database of Systematic Reviews. Relevant studies from Google Scholar were also included.

RESULTS

The overall prevalence of AFM1 in all dairy products was 66.2% (95% CI 60.6 to 71.9%), with high heterogeneity (I²=99.7%, Q statistic=2221.03, p<0.0001). The prevalence for specific dairy products was as follows: raw milk, 64.8% (95% CI 60.9 to 68.7%); pasteurized milk, 88.7% (95% CI 81.6 to 95.7%); sterilized milk, 71.0% (95% CI 67.2 to 74.8%); ultra-high temperature processing (UHT) milk, 67.9% (95% CI 64.9 to 70.9%); yogurt, 58.8% (95% CI 42.5 to 75.1%); doogh, 17.2% (95% CI 13.9 to 20.5%); and cheese 49.8% (95% CI 47.8 to 51.9%). The overall mean concentration of AFM1 across all dairy products was 57.22 ng/kg (95% CI 46.95 to 67.49), with significant heterogeneity (I²=99.7%, Q statistic=2221.03, p<0.0001). Mean AFM1 levels (ng/kg) for each dairy product were as follows: raw milk, 52.51 (95% CI 40.96 to 64.05); pasteurized milk, 71.14 (95% CI 48.81 to 93.47); sterilized milk, 60.10 (95% CI 30.90 to 89.30); UHT milk, 82.57 (95% CI 35.30 to 129.85); yogurt, 46.74 (95% CI 24.27 to 69.21); and doogh, 41.60 (95% CI 32.60 to 50.60).

CONCLUSIONS

In total, these results highlight the importance of increasing the regulation of animal feed, reducing aflatoxin B1 (AFB1) in animal feed, and monitoring AFM1 in dairy products, particularly raw and heated milk.