Microbial exposure and diversity in Norwegian shrimp processing plants

Seafood processing workers have a high prevalence of respiratory symptoms and occupational asthma, primarily attributed to allergenic protein exposure. However, exposure to airborne microorganisms from raw materials can also contribute to allergic sensitization and other respiratory ailments. This study aimed to assess microbial exposure in shrimp processing plants and identify susceptible work tasks. Full-shift personal air samples were collected from two Norwegian shrimp processing plants across five distinct work processes: thawing, truck driving, cooking-peeling (technician), packing, and flour production. The samples were analyzed for the presence of endotoxin, Toll-Like Receptor (TLR) activation, bacterial and fungal DNA copies, and microbial composition. Endotoxin levels were generally low, with only one sample (98 EU/m3) exceeding the recommended occupational exposure limit (OEL). A significant TLR2 activation was observed among thawers, indicating the presence of microbial ligands capable of triggering an immune response. The median bacterial (75 × 103 DNA copies/m3) and fungal (3,301 × 103 DNA copies/m3) exposure were highest among the flour production workers, while the lowest bacterial and fungal exposure was among packers (1.5 × 103 DNA copies/m3) and technicians (337 DNA copies/m3), respectively. Several bacterial and fungal species were identified, including ten allergenic and sixteen pathogenic species. Sporobolomyces roseus and Saccharomyces cerevisiae were the two most frequently...