FUMONISINS

Comments:

The Committee reviewed the studies that have become available since the previous evaluation in 2011, and concluded that they would not change the overall toxicological assessment performed previously by the Committee. Thus, the previously established group PMTDI of 2 µg/kg bw for FB1, FB2 and FB3, alone or in combination, was retained by the current Committee. The Committee noted that the international exposure estimates for FB1 and total fumonisins were lower than those estimated by the Committee at its seventy-fourth meeting in 2011. In the current assessment, a larger part of the occurrence data was from countries belonging to the WHO European Region compared with 2011, resulting in lower overall fumonisin levels in maize. In the current assessment, no information on fumonisin levels in maize was available from countries belonging to the African, Eastern Mediterranean or South-East Asia regions, where higher fumonisin concentrations are typically detected. Given these limitations of the occurrence data used in the exposure assessment and high exposures reported in the literature in some countries, it is likely that the exposures to fumonisins in areas where maize is a staple food and high contamination with fumonisins can occur are higher than those estimated by the Committee at this meeting, as can be seen in the previous evaluation, which was based on a larger and more representative data set. 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.

Tolerable Intake:

2 µg/kg bw per day (group PMTDI)

Meeting:

83

Report: 

Tox Monograph: 

Comments:

The previously established PMTDI was retained. The Committee concluded that the estimated dietary exposures to FB1 and total fumonisins would exceed the group PMTDI at the population level in some regions within some countries. The Committee concluded that adverse effects from fumonisin exposure may occur and that reduction of exposure to fumonisin and other toxins produced by F. verticillioides is highly desirable, particularly in areas of the world where maize is a major dietary staple food and where high contamination can occur. As fumonisins do not carry over from feed to animal products in significant amounts, the occurrence of fumonisins in feed was considered not to be a human health concern. The Committee concluded that implementation of the MLs proposed byCCCF could significantly reduce exposure (by more than 20%) to total fumonisins in six clusters (A, B, D, F, G, K), mainly due to the proposed Codex ML for the category “corn/maize grain,unprocessed”. The Committee noted that implementation of the proposed MLs would result in rejection of 1–88% of “corn/maize grain, unprocessed” and 4–57% of “corn/maize flour/meal” across the clusters. The Committee also noted that the exceedance of the PMTDI occurs only in limited regions presenting high maize consumption levels and highly contaminated maize. The Committee concluded that no or little effect on the international exposure estimates was noticed as a result of implementing MLs higher than those proposed by CCCF.

MRL Comment:

CCCF's proposed MLs for fumonisins (FB1 + FB2) in maize: “corn/maize grain, unprocessed” (ML =5000 μg/kg), “corn/maize flour/meal” (ML = 2000 μg/kg), “popcorn grain”(ML = 2000 μg/kg), “maize-based baby food” (ML = 500 μg/kg) and “maize-based breakfast cereals, snacks and chips” (ML = 1000 μg/kg)

Intake:

FB1: 10−3 to 7.6 μg/kg bw/d (mean), 33.3 μg/kg bw/d (95th percentile). Total fumonisins: 0.087 × 10−3-14.14 μg/kg bw/d (mean), 44.8 μg/kg bw/d (95th percentile). Maize predominant source of exposure.

Tolerable Intake:

2 µg/kg bw per day (group PMTDI)

Meeting:

74

Report: 

Addendum: 

Comments:

The Committee concluded that nephrotoxicity was the most sensitive toxic effect of pure fumonisin B1, as the available studies clearly indicated that long-term renal toxicity is a prerequisite for renal carcinogenesis. The Committee allocated a group provisional maximum tolerable daily intake (PMTDI) for fumonisins B1, B2, and B3, alone or in combination, of 2 µg/kg bw per day on the basis of the NOEL of 0.2 mg/kg bw per day from a 90-day oral toxicity study in rats and a safety factor of 100. All of the estimates of intake of fumonisin B1 were well below the group PMTDI, even when intake estimates for fumonisin B1 are increased by 40% to account for the presence of fumonisins B2 and B3. The Committee was aware of an unpublished risk assessment in which the data on renal tumours had been used, and noted that the estimated risk was negligible at intakes below the group PMTDI established at the present meeting.

Intake:

Estimated dietary intakes based on the GEMS/Food regional diets and a published distribution of the concentrations of fumonisin B1 in maize derived a range of mean intake values for fumonisin B1 of 0.2 µg/kg bw per day in the European-type diet to 2.4 µg/kg bw per day in the African diet. Published mean estimates of national intake of fumonisin B1 ranged from 0.02 µg/kg bw per day to 1.0 µg/kg bw per day. These estimates also included certain assumptions that ensure conservatism, such as the assumption that all persons consume food containing fumonisins B1 at the default concentration.

Tolerable Intake:

PMTDI for fumonisins B1, B2, and B3, alone or in combination: 2 µg/kg bw/d

Meeting:

56

Report: 

Tox Monograph: