Evaluation of Simultaneous Exposure to Flour Dust and Airborne Fungal Spores in Milling Plant

Wheat flour as an organic allergen particle has an extensive respiratory exposure in milling industry and related industries. Simultaneous exposure to flour dust and fungal spores causes infectious disease, cancers, and impaired pulmonary function tests. This research was carried out with the aim of assessing the concentration of respirable flour particles, determining the type, and concentration of fungal spores in breathing air of workers in milling industries. In this descriptive cross-sectional study, 42 area samples were collected on filter and analyzed gravimetrically. Using a specific sampling pump, sampling of bioaerosols and sabro dextrose agar medium of fungal spores, was performed. Microscopic analysis was applied to detect and quantify microorganisms as colony per cubic meter. The mean and standard deviation of total respirable particles in the breathing air of workers was 6/57±1/69mg/m3, which exceeded occupational exposure limit. The concentration of fungal spores in workers’ breathing air ranged from 42 to 310 colony per cubic meter. The percentage of respirable to total dust particles produced in sieve vibration, bagging, and milling sections, were determined 67.83%, 32%, and 62.2%, respectively. The results of this study revealed that the concentration of respirable particles in wheat milling process exceeded the recommended level and the concentration of fungal spores was at the average level of occupational exposure according to ACGIH recommendation. Therefore, engineering controls are required in flour milling process to reduce the exposure of workers.