Survival and Outgrowth of Clostridium botulinum Type E Spores in Smoked Fish

Abstract

Chub injected in the loin muscle with 106Clostridium botulinum type E spores were smoked to an internal temperature of 180 F (82.2 C) for 30 min, sealed in plastic bags, and incubated at room temperature (20 to 25 C) for 7 days. Viable type E spores were found in practically all such fish. Toxin formation by the survivors in the smoked fish was dependent on the brine concentration of the smoked fish. A brine concentration of 3% or higher, as measured in the loin muscle, inhibited toxin formation. Six different type E strains gave similar results. Only a few hundred of the million spores in the inoculum survived the smoking. Moisture in the atmosphere during smoking did not reduce the incidence of fish with type E survivors.