Occupational exposure to bioaerosols in Norwegian crab processing plants

INTRODUCTION: Aerosolization of components when processing king crab (Paralithodes camtschaticus) and edible crab (Cancer pagurus) may cause occupational health problems when inhaled by workers. METHODS: A cross-sectional study was carried out in three king crab plants and one edible crab plant. Personal exposure measurements were performed throughout work shifts. Air was collected for measurement of tropomyosin, total protein, endotoxin, trypsin, and N-acetyl-beta-d-glucosaminidase (NAGase). T-tests and ANOVAs were used to compare the levels of exposure in the different plants and areas in the plants. RESULTS: Total protein and tropomyosin levels were highest in the edible crab plant, endotoxin levels were highest in king crab plants. King crab exposure levels were highest during raw processing. Tropomyosin levels were highest during raw king crab processing with geometric mean (GM) 9.6 versus 2.5ng m-3 during cooked processing. Conversely, edible crab tropomyosin levels were highest during cooked processing with GM 45.4 versus 8.7ng m-3 during raw processing. Endotoxin levels were higher in king crab plants than in the edible crab plant with GM = 6285.5 endotoxin units (EU) m-3 versus 72 EU m-3. In the edible crab plant, NAGase levels were highest during raw processing with GM = 853 pmol4-methylumbelliferone (MU) m-3 versus 422 pmol4-MU m-3 during cooked processing. Trypsin activity was found in both king crab and edible crab plants and levels were higher in raw than cooked processing. Differences in exposure levels between plants and worker groups (raw and cooked processing) were identified. CONCLUSIONS: Norwegian crab processing workers are exposed to airborne proteins, tropomyosin, endotoxins, trypsin, and NAGase in their breathing zone. Levels vary between worker groups and factories