Exposure assessment to staphylococcus enterotoxins in Nile tilapia (Oreochromis niloticus) supplied through semi-regulated and unregulated value chains

Abstract The objective of this study was to estimate the risk associated with staphylococcal enterotoxin (SE) exposure from the consumption of Nile tilapia supplied through the semi-regulated and unregulated value chain in Kenya. The fish supply chain was modeled from landing to consumption of unprocessed (fresh) and processed (salted and sun dried, smoked, filleted) fish. Data related to prevalence of Staphylococcus aureus in fish, taking into account survey information on handling, storage, processing and consumption of Nile tilapia were collected from recently completed studies in Kenya. Other model inputs were complemented with data from published and unpublished literature. A probabilistic exposure model was developed with Monte Carlo simulation in Excel add-in software using @Risk software. The simulated levels of S. aureus in fish after handling and storage of salted and sun dried and smoked fish ranged between 4 log CFU/g and 9.01 log CFU/g (maximum population density), while in fillet, levels of S. aureus following growth during display at retail shops was between 3.10 log CFU/g (5% percentile) and 9.01 log CFU/g (95% percentile). Estimated SE dose per-serving in fish supplied after processing was significantly higher (p