Airborne levels of alpha-amylase allergens in bakeries

In the baking industry the use of enzymes has increased throughout the 1980s. Several studies have reported sensitization and respiratory disorders among bakery workers caused by enzymes in dough improvers. Fungal alpha-amylase is the most frequently reported cause of allergy. alpha-Amylase allergen exposure levels in the bakery industry, however, have not yet been reported.

The main objective of this study was to quantify personal alpha-amylase exposure levels of bakery workers.

alpha-Amylase allergens were measured in 507 personal samples of airborne dust taken in bakeries by using a newly developed sandwich enzyme immunoassay with affinity-purified polyclonal rabbit IgG antibodies. A cascade impactor was used to estimate the size of dust particles carrying alpha-amylase allergens.

The rabbit IgG antibodies used in the assay showed, in immunoblotting with commercially available alpha-amylase, a reaction profile very similar to that of IgE from sensitized bakers. The enzyme immunoassay appeared to be highly specific for fungal amylase. Allergen exposure levels varied considerably among bakery workers, depending on the type of bakery and job category (range, 0 to 40 ng/m3). In confectioneries no alpha-amylase allergens were detected. In other bakeries alpha-amylase exposure was only found for workers directly involved in dough making. Measurements of the particle size distribution in these bakeries showed that alpha-amylase allergens are most likely to be deposited in the nose and ciliated airways.

This study shows that personal monitoring of fungal amylase allergen exposure in bakeries is possible. This permits the identification of high-risk tasks and allergen sources, as well as the study of exposure-response relationships.