Allergies in the workplace a pilot study of exposure to flour dust and allergens in Cape Town bakeries

Abstract

Background: A pilot study was performed as part of a large exposure assessment study, with the aim of documenting variability in environmental exposure and high-risk work processes/job types in bakeries of varying sizes in a large supermarket chain store in the Western Cape province of South Africa. The results of this pilot study have been used to design the measurement strategy for the main exposure study. Methods: Personal inhalable flour dust samples w ere collected on randomly selected individuals within each job category (bread baker, baker controller, confectioner, counterhand, cleaner). The samples were analysed for particulate mass and specific flour dust allergens (w heat and -amylase allergens). Exposure metrics were developed on the basis of individually measured exposures and average levels of these personal samples within each job category. Surface samples collected w ere analysed for presence of other bio contaminants such as house-dust mite and mould. Results: A total of 42 full-shift personal samples were collected and analysed. Personal sampling revealed moderate variation across job titles in flour- dust concentration. Bread bakers had the highest average (geometric mean (GM )) flour-dust concentration (0.904 mg/m3), followed by confectioners (0.539 mg/m3) and bakery controllers (0.289 mg/m3), with counterhands having the lowest average exposures (0.125 mg/m3). Similarly, in respect of the distribution of wheat allergen levels, bakers had the highest average (GM ) allergen concentration (16.504 µg/m3), followed by confectioners (7.307 µg/m3), with counterhands the lowest (0.84 µg/m3). There was a significant degree of correlation between general dust levels and wheat allergen concentrations (Spearman r = 0.91). Surface samples demonstrated the presence of house-dust mite and mould species Aspergillus and Penicillium sp. Conclusion: This study demonstrates that bread bakers have the highest and counterhands the lowest flour-dust and wheat-allergen exposures. The findings also suggest that flour-dust particulate exposure could be used as a proxy for w heat-allergen concentrations. The results of this study have been used to optimise the study design for the larger exposure assessment study to flour dust-allergens (wheat, rye and fungal -amylase) among supermarket bakery workers in the Western Cape.