Exposure to flour dust in South African supermarket bakeries: modeling of baseline measurements of an intervention study.
BACKGROUND
Exposure to flour dust has been reported as an important risk factor for allergic respiratory disease among bakery workers. A high prevalence of allergic sensitization and asthma was recently reported in South African supermarket bakeries. The aim of this study was to conduct a detailed exposure assessment of these bakeries so as to provide the baseline for a broader intervention study.


METHODS
A total of 211 full-shift personal samples were collected on randomly selected individuals within five different job categories in 18 bakeries. The samples were analyzed for particulate mass and specific flour dust allergens (wheat, rye, and fungal alpha-amylase). Exposure models were developed using job, bakery size, tasks, and specific ingredients used. Bakery and worker were regarded as random effect components.


RESULTS
Bread bakers had the highest average (geometric mean) exposures (1.33 mg m(-3) flour dust particulate, 13.66 microg m(-3) wheat allergens, and 5.14 microg m(-3) rye allergens). For alpha-amylase allergens, most samples were below the limit of detection for several occupational titles. In the mixed effect models, the significant predictors of elevated exposure to inhalable dust particulate as well as wheat and rye allergen concentrations were large bakery size, bread baking, and use of cereal flours, while tasks such as confectionery work were negatively correlated with these exposure metrics. Weighing tasks and use of premix products were associated with increased exposure to fungal alpha-amylase. A high correlation between particulate dust and wheat (r = 0.84) as well as rye (r = 0.86) was observed, with a much lower correlation between particulate dust and fungal alpha-amylase (r = 0.33). Overall, a low proportion (39%) of bakery stores implemented various control measures to reduce dust exposures in the bakeries.


CONCLUSIONS
This study confirms that current exposure control strategies in supermarket bakery stores are inadequate in reducing dust exposures to protect the health of bakery workers.
Baatjies
Roslynn
R
Department of Environmental and Occupational Studies, Faculty of Applied Sciences, Cape Peninsula University of Technology, Cape Town 8001, South Africa.
Meijster
Tim
T
Lopata
Andreas
A
Sander
Ingrid
I
Raulf-Heimsoth
Monika
M
Heederik
Dick
D
Jeebhay
Mohamed
M
D000395:Air Pollutants, Occupational / Q000032:analysis* / Q000592:standards; D016902:Air Pollution, Indoor / Q000032:analysis / Q000706:statistics & numerical data; D000485:Allergens / Q000032:analysis; D001249:Asthma / Q000453:epidemiology; D001939:Bread; D003296:Cooking / Q000592:standards / Q000706:statistics & numerical data; D004391:Dust / Q000032:analysis*; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D005433:Flour / Q000032:analysis* / Q000592:standards; D005525:Food-Processing Industry / Q000706:statistics & numerical data; D005658:Fungi / Q000201:enzymology; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis / Q000592:standards / Q000706:statistics & numerical data; D009784:Occupational Diseases / Q000453:epidemiology; D016273:Occupational Exposure / Q000032:analysis / Q000592:standards / Q000706:statistics & numerical data*; D011482:Protective Devices / Q000706:statistics & numerical data; D012130:Respiratory Hypersensitivity / Q000453:epidemiology; D012307:Risk Factors; D013019:South Africa / Q000453:epidemiology; D000516:alpha-Amylases / Q000032:analysis
D000395:Air Pollutants, Occupational; D000485:Allergens; D004391:Dust; D000516:alpha-Amylases