Aflatoxin and ochratoxin A residues in supplementary foods used for wild birds

Provision of supplementary food for garden birds is practiced on a large scale in multiple countries. While this resource has benefits for wild bird populations, concern has been expressed regarding the potential for contamination of foodstuffs by mycotoxins, and the implications this might have for wildlife health. We investigated whether aflatoxin (AF) and ochratoxin A (OA) residues are present in foodstuffs sold for wild bird consumption at point of sale in Great Britain using high pressure liquid chromatography analyses. The hypothesis that production of these mycotoxins occurs in British climatic conditions, or under storage conditions after the point of sale, was tested under experimental conditions but was not proved by our study. While the majority of peanut samples were negative for AF residues, 10% (10/98) of samples at point of sale and 11% (13/119) of those across the storage and climate exposure treatment replicates contained AFB₁ that exceeded the maximum permitted limit of 20 μg/kg. No significant difference was found in the detection of either mycotoxin between branded and non-branded products. The clinical significance, if any, of exposure of wild birds to mycotoxins requires further investigation. Nevertheless, the precautionary principle should be adopted and best practice steps to reduce the likelihood of wild bird exposure to mycotoxins are recommended.