Thermal Inactivation of Type E Botulinum Toxin1

Abstract

The theoretical required cooking times for inactivation of type E Clostridium botulinum toxin (5,000 LD5o mouse units per 0.5 ml) in haddock fillets of various sizes were calculated by graphical integration of the toxin inactivation rate and heat penetration data. The results indicated that normal cooking procedures should suffice to inactivate this amount of toxin. This conclusion was substantiated by the following additional experimental observations which revealed that the original experiments had been conducted under conservative conditions. First, maximal heat stability of the toxin was found to occur at about pH 5.5, with decreasing resistance upon increasing pH. The theoretical cooking times were based on destruction of the toxin at pH 6.7. The pH of radio-pasteurized inoculated haddock, when toxin production had occurred, was on the alkaline side, at which condition the toxin is heat-labile. Second, when spoilage was discernible in radiopasteurized inoculated haddock, the toxin titer was low, about 50 LDto mouse units per 0.5 ml. Third, the toxin was adequately inactivated in toxic fillets after deep-fat frying for 3 min at 375 F (190.6 C) or after pan frying for 5 min per side at 400 F (204.4 C). Fourth, in this study, residual toxin activity was assayed by intraperitoneal iniection of mice. It was shown that the oral toxic dose was 50 to 100 times greater than the intraperitoneal toxic dose.

Thermal Inactivation of Botulinum Toxins in Canned Salmon

“…minutes at 71°C, 5-35 minutes at 74°C, and a maximum of 5 minutes at 85°C. As has been reported previously, toxicity remained longer if the original levels were higher (Scott andStewart, 1950, andLicciardello et al, 1967).…”

“…encing heat stability were not held constant. In our tests, the type E toxin was considerably more stable than reported by Ohye and Scott (1957); Licciardello, Nickerson, Ribich, and Goldblith (1967); and Yao, Denny, and Bohrer (1973).…”

“…The heat treatment recommended to inactivate botulinum toxins has been to exceed the minimum temperature of 80°C to allow a considerable margin of safety to cover possible protective effects of the food (Scott and Stewart, 1950). For botulinum toxin type E, normal cooking procedures, e.g., frying, have been found to be adequate, as was a temperature of 77°C for less than 1 minute (Licciardello et al, 1967). The recommendation of the U.S.D.A.…”

Susceptibility of Mink to Clostridium Botulinum Type E Toxin

“…Similar experiments aiming at determining the relation between the oral and intraperitoneal lethal doses of Clostridium botulinum type E toxin in mice have been performed by Licciardello et al (1967). They found that the oral lethal dose was 50--100 times greater than the intraperitoneal dose, and this corresponds fairly well with the results obtained in these experiments.…”

Guidance on date marking and related food information: part 1 (date marking)

“…The pathogen is relevant for chilled foods under reduced oxygen packaging (ROP), in particular foods of the RePFED category that have not been processed to eliminate the spores (see Section 3.2.1.2) or the physico‐chemical characteristics do not inhibit their growth (see Section 3.2.2) (Notermans et al., 1990; Peck, 1997; FSA 2017). Compared to other bacterial toxins, those of non‐proteolytic C. botulinum can be heat inactivated by normal food cooking procedures (Licciardello et al., 1967; Wachnicka et al., 2016).…”