Aflatoxin M1 Occurrence in Dairy Products Worldwide: Summary of Literature Review and Policy Implications

Research has suggested that mammals that consume aflatoxin B1 (AFB1, the most common and toxic of the aflatoxins) secrete a metabolite of AFB1 in their milk referred as aflatoxin M1 (AFM1). In lieu of fully understanding the human health risks and thus designing food safety standards appropriately, regulatory agencies have set standards for AFM1 in milk and dairy products simply based upon taking the existing AFB1 standard (in a given nation), and dividing by a factor that roughly estimates how much AFM1 is produced in milk when “parent” aflatoxin is present in dairy animals’ diets. But as more and more nations are suffering economic losses due to AFM1 in dairy products exceeding allowable limits – particularly the European Union limit of 0.05 μg/kg (which is extremely difficult to meet) – there is need to better characterize the true human health risk of this chemical in our daily diets, to inform policy decision-making and public health officials on the true nature of the risk. This information is urgently needed because of recent discoveries of putative associations between aflatoxin and stunting, as well as the lack of general (public and policy-making as well as non- specialized scientists) knowledge of the difference between the toxicity of AFB1 and AFM1. There is a critical need to compare both the toxicity of and the exposure to AFM1 with AFB1 to be able to judge relative risks. It is also important to understand whether AFM1, like AFB1, has a toxicological interaction with HBV infection to increase liver cancer risk and to compare exposure patterns to these two chemicals. In several Feed the Future countries, high AFM1 contamination levels have been detected in milk. Unfortunately, people have assumed AFM1 is just as toxic as AFB1. Consequently, newspaper headlines have warned people to avoid drinking locally produced milk and this has set back early childhood milk-based nutrition interventions and paralyzed the dairy industry in Ethiopia, for example. Similar headlines have been published in other countries like Kenya. Research is urgently needed to inform policy makers about the true and relative risk of AFM1 in milk. Towards this goal, this study represents the first (of two) stages of work in a global risk assessment of aflatoxin M1 (AFM1). Authors of this study conducted a literature review on the health effects of AFM1 through toxicological and limited human studies. In addition to this, they also found substantial occurrence data for AFM1 in milk and dairy products worldwide. This paper presents the findings of this desk review and makes policy recommendations for reducing AFM1 exposure in human populations worldwide.