AFLATOXINS

Comments:

The Committee reaffirmed the conclusions of the forty-ninth meeting of JECFA that aflatoxins are among the most potent mutagenic and carcinogenic substances known, based on studies in test species and human epidemiological studies, and that hepatitis B virus (HBV) infection is a critical contributor to the potency of aflatoxins in inducing liver cancer. At the eighty-third meeting the Committee also evaluated co-exposure to aflatoxins and fumonisins. Fumonisins and aflatoxins are both frequent contaminants in cereals and cerealbased foods. Aflatoxins are common contaminants in groundnuts and tree nuts. Co-exposure to both mycotoxins is likely in areas where these foods are regularly consumed. Although evidence in laboratory animals from the previous and the present evaluations has suggested an additive or synergistic effect of fumonisin and aflatoxin co-exposure in the development of preneoplastic lesions or hepatocellular carcinoma, currently no data are available on such effects in humans. The Committee concluded that there are few data available to support co-exposure as a contributing factor in human disease. However, the interaction between AFB1, a compound with known genotoxic properties, and fumonisins, which have the potential to induce regenerative cell proliferation (particularly at exposures above the PMTDI), remains a concern. This is due to the fact that the incidences of chronic liver disease and stunting are high in the areas of the world where the exposures to both mycotoxins are high and the co-exposure has been confirmed with biomarkers.

Intake:

On request of the CCCF, the Committee performed an impact assessment of different MLs for ready-to-eat peanuts and concluded that enforcing a maximum limit (ML) of 10, 8 or 4 µg/kg for ready to-eat peanuts would have little further impact on dietary exposure to AFT for the general population, compared with setting an ML of 15 µg/kg. At an ML of 4 µg/kg, the proportion of the world market of ready-to-eat peanuts rejected would be approximately double the proportion rejected at an ML of 15 µg/kg (about 20% versus 10%).

Tolerable Intake:

NOT ESTABLISHED, genotoxic carcinogen

Meeting:

83

Report: 

Tox Monograph: 

Comments:

Aflatoxins are considered to be genotoxic carcinogens that induce tumors in the liver of animals and humans. Aflatoxin B1 is the most potent carcinogen of the aflatoxins; most of the toxicological data available are related to aflatoxin B1. The carcinogenic potency of aflatoxins in HBsAg+ individuals is substantially higher than the potency in HBsAg- individuals, with values of 0.3 and 0.01, respectively. These potency estimates were derived from the results of epidemiological studies conducted in areas with a high prevalence of liver cancer and with high levels of aflatoxin-contamination in foodstuffs. The Committee concluded that reduction of the intake of aflatoxins in populations with a high prevalence of HBsAg+ individuals will have greater impact on reducing liver cancer rates than reductions in populations with a low prevalence of HBsAg+individuals.

Intake:

The Committee decided to base the assessment of the impact of different MLs for aflatoxin (AFL) exposure on data provided by producing countries, noting that these better represent the materials in commerce and result in a robust estimate of AFL dietary exposure from the tree nuts. Consumption of almonds, Brazil nuts, hazelnuts, pistachios, and dried figs contributes greater than 5% of the total AFL dietary exposure in only five of the 13 GEMS/Food cluster diets (Clusters B, C, D, E and M). If fully enforced, an ML at 20 µg/kg in hazelnuts, almonds, pistachios, Brazil nuts, and dried figs would only have an impact on the relative contribution to AFL dietary exposure in these clusters, including high-level consumers of tree nuts. This contribution is due solely to the elevated AFL level in pistachios. For tree nuts other than pistachios, the presence of an ML has no effect on AFL dietary exposure. Moreover, the Committee concluded that enforcing an ML of 15, 10, 8, or 4 µg/kg, would have little further impact on the overall dietary exposure to AFT in all five of the highest exposed population groups compared to setting an ML of 20 µg/kg. Regarding dried figs, the Committee concluded that whatever the hypothetical ML scenario applied (no ML, 4, 8, 10, 15, or 20 µg/kg) there would be no impact on the overall dietary exposure to AFL. The Committee noted that the reduction of AFL dietary exposure is an important public health goal; particularly in populations who consume high levels of any potentially AFL contaminated food.

Tolerable Intake:

NOT ESTABLISHED, genotoxic carcinogen

Meeting:

68

Report: 

Tox Monograph: