“Estimates of chronic dietary exposure to zearalenone based on the available occurrence data are below or in the region of the tolerable daily intake (TDI) for all age groups and not a health concern,” found the European Food Safety Authority (EFSA)’s Panel on Contaminants in the Food Chain Panel (CONTAM).
And the Panel has set a tolerable daily intake (TDI) for zearalenone of 0.25 μg/kg body weight (b.w.) based on its reported oestrogenic effects.
Cereals toxin
Zearalenone is a mycotoxin produced by several Fusarium species. It is commonly found in maize but can be found also in other crops such as wheat, barley, sorghum and rye.
Whilst zearalenone is primarily a field contaminant, toxin production may also occur under poor storage conditions. It is generally stable during cooking, except under alkaline conditions or during extrusion cooking, reports EFSA.
Adverse effects of zearalenone on testosterone synthesis, sexual behaviour, sex organ weights, testicular histology and spermatogenesis have been observed in male animals, notes the risk assessor.
While in female pigs, it reports, the tissues that are most sensitive to the oestrogenic effect of zearalenone and its metabolites are the ovary, uterus and vulva.
Brussels request
The European Commission asked the risk assessor to see whether a potential increase in the maximum level (ML) for the toxin in breakfast cereals would result in chronic dietary exposure.
The request also specified a review of the earlier opinion of the Scientific Committee on Food (SCF) in the light of results of more recent toxicological studies.
In 2000, the SCF set a temporary TDI (t-TDI) of 0.2 µg/kg body weight for zearalenone.
The CONTAM panel reports that a number of relevant studies have become available since the previous t-TDI was established by the SCF, and it concluded that a full TDI of 0.25 μg/kg b.w. can now be established.
The Parma based agency notes in its new evaluation that the possible impact of combined exposure to zearalenone with other oestrogenic substances in food (such as phytoestrogens in soya) or the environment “could be additive or antagonistic”.
Breakfast cereals
According to the Parma based agency’s estimates, a potential increase in the ML for zearalenone in breakfast cereals, from 50 µg/kg up to 150 µg/kg, is unlikely to result in a chronic dietary exposure.
“In a worst case scenario it is possible that an individual could consume the same batch of breakfast cereal containing zearalenone at the ML every day for 2 to 4 weeks, in which case exposures may exceed the TDI,” commented CONTAM.
Food samples
The assessors, in weighing up the risk from exposure, looked at a total of 13,075 analytical results obtained from food samples and 9,877 results on unprocessed grains sampled by 19 European countries in 2005-2010. These were generated by a call for data in July last year.
From the average values across the European countries, breakfast cereals provide a contribution of 0.4-17 per cent to total dietary exposure of zearalenone in adults, noted the CONTAM panel.
The highest concentrations of zearalenone were reported for wheat bran, corn and products thereof such as breakfast cereals like cornflakes.
Grains and grain-based foods, in particular grains and grain milling products, bread and fine bakery wares, made the largest contribution to the estimated zearalenone exposures, reported EFSA.
The full EFSA opinion can be read here.