A predictive model for taste taint accumulation in Recirculating Aquaculture Systems (RAS) farmed-fish – demonstrated with geosmin (GSM) and 2-methylisoborneol (MIB)

The accumulation of “earthy” or “muddy” off-flavours due to taste taint accumulation as geosmin (GSM) or 2-methylisoborneol (MIB) in the flesh of fish from Recirculated Aquaculture Systems (RAS) is a major concern globally. To aid RAS farm management a time dependent concentration predictive model was developed. The model is a sum of two exponential terms with time that simulate simultaneous taint uptake and elimination. Illustrative simulations for RAS barramundi (Lates calcarifer) a premium fish grown at a water temperature of 28°C show that the threshold for consumer rejection of 0.70μgkg−1 MIB will be reached at 225 days. At a typical RAS harvest of 240 days the concentration of MIB is predicted to be four (4) times that for GSM. Because model predictions showed good agreement with independent data for both RAS barramundi and rainbow trout (Oncorhynchus mykiss) it was concluded the model was free of programming and computational errors and of a generalized form. Model simulations revealed a 5°C variance in RAS growth temperature did not meaningfully impact taint accumulation as either GSM or MIB. A major benefit to the RAS industry is that model simulations can be used to investigate a range of growth protocols in RAS farming to limit taint. An advantage is the model can be conveniently simulated in standard spread-sheeting tools.