Occupational sensitization to fungal enzymes used in animal feed industry

Industrial enzymes cause the increasing prevalence of occupational hypersensitivity. Our objective was to study workers occupationally exposed to fungal enzymes in 2 animal feed factories to determine if the sensitization originated in the enzymes or was caused by the microorganism used to produce the enzymes.

Eighty-six consenting workers were studied by skin prick tests with extracts from the enzymatic products handled in their factories. Positive workers were then studied by IgE immunoblotting and basophil activation was measured by flow cytometry.

Eight of the 86 workers analysed (9%) tested positive and were more frequently sensitized to phytase from Trichoderma and Peniophora. Glucanase and alpha-amylase from Bacillus amyloliquefaciens did not cause sensitization in any worker. No cross-reactions were observed between Trichoderma and Peniophora sp. phytases. Workers were sensitized to the product that they handled.

Fungal enzymes cause occupational hypersensitivity in animal feed industries. Immunoblotting and basophil activation are useful to evaluate the effects of handling enzymes as part of the medical surveillance of enzyme-exposed workers. We describe Peniophora sp. 6-phytase as a new allergen and enzymes from Trichoderma as strong sensitizers.