Inhibition of Clostridium botulinum Type E Toxin Formation by Potassium Chloride and Sodium Chloride in Hot-Process (Smoked) Whitefish (Coregonus clupeaformis)

Abstract

Whitefish steaks were brined in NaCl, KCl, or equimolar NaCl:KCl to contain similar chloride ion concentration and inoculated intramuscularly with 10 or 100 spores of Clostridium botulinum type E per gram of fish. Steaks were then heated in a simulated (i.e., without smoke) hot-smoke process to internal temperatures of 62.8° to 76.7°C (145°–170°F) for the final 30 min of a 2- to 3-h process, packaged under vacuum in oxygen-impermeable film, and stored at abuse temperature of 25°C. During 7 d of storage, toxin production was inhibited in steaks containing more than 0.66 ionic strength NaCl, 0.64 KCl, or 0.71 equimolar NaCl:KCl. The results indicate that it is feasible to substitute KCl for NaCl in hot-process smoked fish for inhibition of outgrowth and toxin production by Clostridium botulinum type E.