Prevalence and concentration of aflatoxin M1 in milk and dairy products: an umbrella review of meta-analyses
Abdolreza Sotoodeh Jahromi, Mohammad Jokar, Arman Abdous, Mohammad Hasan Rabiee, Farzad Heydari Bahman Biglo, Vahid Rahmanian
Abstract
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.