Introduction and Objectives Bakers have one of the highest incidence rates of occupational asthma. This is related to the levels of dust generated in bakeries from both flour itself and ‘improvers’, which are added to flour to improve the quality of the bread. Bakery improvers can contain known allergens such as fungal alpha amylase, hemicellulase and soya trypsin inhibitor from soya flour, as well as vegetable oil, calcium sulphate and emulsifiers; usually consisting of organic esters and calcium silicate. This study investigated changes to the ‘dustiness’ of flour by altering the proportions of improvers in the mix, and measured any concomitant reduction in allergen exposure resulting from these changes.

Methods The concentration of calcium sulphate, calcium silicate and vegetable oil were manipulated in a standard improver mix. Both standard ‘dustiness’ tests and simulation of bakery activities were undertaken. Atmospheric levels of total soluble protein, wheat flour antigen, soya trypsin inhibitor and calcium were measured.

Results The most effective method of decreasing dustiness of improvers and exposure to allergens was to increase the vegetable oil content of the improver. Raising the oil from 2% to 4% of the improver mix was associated with a 77% decrease in airborne wheat flour antigen and soya trypsin inhibitor in the simulation. Reducing the calcium sulphate content reduced the dustiness of the improver, measured by gravimetric analysis. However, the effect on the atmospheric levels of allergens was less clear. Reducing the calcium silicate content within the emulsifier mix was the least effective of the three methods tested.

Conclusions Changing the formulation of the improver represents a simple, practical and inexpensive method of reducing the dustiness and potential exposure to allergens in bakery workers. This study has shown that a small increase in the oil content would be an effective method for reducing bakers’ exposure to allergens and dust. However it could affect how easily the improver is blended and so could be subject to limitations. ©Crown copyright (2010).