Germination, Growth, and Toxin Production of Nonproteolytic Clostridium botulinum as Affected by Multiple Barriers

Abstract

The effect of combinations of pH (6.5, 5.75), NaCl (0.25, 1.75%), and incubation temperatures (7, 13 Њ Њ Њ Њ ЊC) on spore germination, outgrowth, and time to toxicity of nonproteolytic Clostridium botulinum was examined in a broth system. Spores of four toxin type E and nonproteolytic type B were inoculated (10 4 /ml) into Tryptone Peptone Glucose Yeast Extract (TPGY) broth. Cultures were monitored for three weeks, or until toxin was detected. A modified FSIS-amplified ELISA (comparable in sensitivity to the mouse bioassay) was used to screen cultures for neurotoxin. Combinations of the most inhibitory level for each barrier reduced the degree and rate of germination, the lag and growth rate of vegetative cells, and the time to toxicity.

Study ofClostridium botulinumby Various Formulations of Salt and Preservatives in Persian Caviar

“…Freezing prevents germination, growth, and toxin production of C. botulinum. It has a slight lethal action on vegetative cells, but it does not affect spores or toxin (Hobbs, 1976;Elliott and Schaffner, 2001). Refrigerated storage of products at <38C is an adequate control of growth and toxigenesis by type E (Graham et al 1997) but once again, the preformed toxin is stable at refrigerated temperatures.…”

“…It has also been found in the gills and viscera of fish, crabs, and shellfish. It is capable of growth in low temperature (3.38C), different sodium chloride (NaCl) concentrations (4.5-5%), and anaerobic conditions (Elliott and Schaffner, 2001).…”

Exposure assessment model to combine thermal inactivation (log reduction) and thermal injury (heat-treated spore lag time) effects on non-proteolytic: Clostridium botulinum

“…(7) Equation 6 is applied in presence of heattreatment, i.e. when the temperature is equal to or greater than 70ºC (Elliott & Schaffner 2001), Equation 7 is applied otherwise.…”