Tasked based assessment of dairy worker exposure to bioaerosols

![CDATA[Objective: The evaluation of dairy worker bioaerosol exposures among similar exposure groups (SEGs) to identify high risk tasks. The data is an important step in the development effective workplace intervention strategies to reduce bioaerosol exposure and health effects. Methods: Inhalable bioaerosol samples were collected in workers’ breathing zones (n=116) over entire work shifts using Button samplers loaded with PVC filters to measure organic dust, endotoxin (rFC assay), and 3-hyrdoxy fatty acids (3-OHFA), ergosterol and muramic acid (GC/MSMS). Ammonia was measured with ToxiRaes. To our knowledge this is the first study with combined 3-OHFA, muramic acid and ergosterol exposure analysis in dairies. SEGs were defined through observation of worker activities and location including: milking and parlor maintenance (33% of population), medical, maternity and calves (24%), mixed tasks (20%), re-bedding stalls (8%), other tasks (5%), feeding (4%), moving stock (3%) and maintenance (3%). Results: Participants were predominantly male (88%) Hispanics (91%) aged 25 to 40 years. Exposures to endotoxin (R2= 33.0% p<0.001), 3-OHFA (25.7% p<0.001), ammonia (18.0% p=0.008) and organic dust (13.9% p=0.022) differed significantly by SEG. 89% of workers had geometric mean endotoxin exposures that exceeded the recommended exposure limit (90 EU/m3), as did 12% of worker exposures to organic dust (2.5 mg/m3). The milking parlor, stock moving and mixed task SEGs had the greatest endotoxin and organic dust exposures. In contrast, the other task SEG, which included administration workers and facility managers, replaced the mixed tasks SEG for the greatest 3-OHFA exposures. The stock movers had the highest mean muramic acid and ammonia exposures. Conclusions: The finding that the majority of the dairy workers had endotoxin exposures that exceeded the recommended guideline indicates a need for a facility wide intervention strategy. Initial strategies should target milking, stock moving, other and mixed task SEGs which represented the greatest overexposure risk.]]