Thermal inactivation of Escherichia coli O157:H7 and Salmonella on catfish and tilapia Original Research Article

Thermal inactivation kinetics of individual cocktails of Escherichia coli O157:H7, or of Salmonella meat isolates or seafood isolates were determined in catfish and tilapia. Determinations were done at 55, 60 and 65 °C using a circulating-water bath and calculated using linear regression analysis. Salmonella seafood and meat isolates D-10 values on the finfish were the same and ranged from 425 to 450, 27.1 to 51.4, 2.04–3.8 s (z = 4.3 °C) at 55, 60 and 65 °C, respectively. The E. coli O157:H7 D-10 values ranged from 422 to 564, 45.2 to 55.5 and 3.3–4.2 s (z = 4.3 °C) at 55, 60 and 65° C, respectively. The only statistical difference (P ≤ 0.05) was found when comparing the D-10 values for E. coli O157:H7 at 55 °C on catfish and tilapia. The other D-10 values for the Salmonella at all temperatures and E. coli O157:H7 at 60 and 65 °C on the catfish or tilapia showed no statistical difference. D-10 values for the catfish and tilapia were significantly lower than the reported values in other food systems, but the z-values were within the literature reported range. These D-10 values can be used to determine cooking parameters of finfish.