Exposure to respirable flour dust and gliadin in wheat flour mills

The aim of this study was to determine the concentrations of respirable flour dusts and gliadin as well as gliadin-specific serum antibodies in exposed workers of Hamadan wheat flour mill factories.

Blood samples from 95 exposed workers and 80 air samples from flour packing, husk packing, flour production and wheat unloading areas were collected. Respirable flour dust density was measured by a gravimetric method, and dust gliadin concentration as well as serum antibodies were determined by enzyme-linked immunosorbent assays.

The Time-weighted average (TWA) flour dust density was higher in all factories (1.56-4.68 mg/m(3)) compared with the threshold limit value (0.5 mg/m(3)) of ACGIH and showed a positive correlation with the gliadin concentration (p<0.05). Additionally, the respirable dust and gliadin concentrations were significantly higher at flour packing workstations compare with the other work areas. Moreover, the mean serum gliadin-specific IgA and IgG and total IgE antibodies were remarkably higher in exposed mill workers compared with the controls (p<0.05).

We clearly demonstrated that workers in Hamadan flour mills are in exposed to a hazardous level of respirable flour dust, receiving the highest level of dust and gliadin in flour packing areas. Furthermore, dust-exposed workers showed upper levels of serum antibodies indicating exposure to higher amounts of allergens than controls.