PREDICTIVE MODEL DESCRIBING THE EFFECT OF PROLONGED HEATING AT 70-TO-80-DEGREES-C AND INCUBATION AT REFRIGERATION TEMPERATURES ON GROWTH AND TOXIGENESIS BY NONPROTEOLYTIC CLOSTRIDIUM-BOTULINUM
Ps. Fernandez et Mw. Peck, PREDICTIVE MODEL DESCRIBING THE EFFECT OF PROLONGED HEATING AT 70-TO-80-DEGREES-C AND INCUBATION AT REFRIGERATION TEMPERATURES ON GROWTH AND TOXIGENESIS BY NONPROTEOLYTIC CLOSTRIDIUM-BOTULINUM, Journal of food protection, 60(9), 1997, pp. 1064-1071
There is growing interest in the food industry in the use of long heat
treatments in the range of 70 to 90 degrees C to produce minimally pr
ocessed foods that have an extended shelf life at refrigeration temper
atures. The risk of growth and toxin production by nonproteolytic Clos
tridium botulinum in these foods is of concern. The effect of heat tre
atments at 70, 75, 80, 85, and 90 degrees C combined with refrigerated
storage for 90 days on growth from 10(6) spores of nonproteolytic C.
botulinum (types B, E, and F) in an anaerobic meat medium was studied.
The following heat treatments prevented growth and toxin production d
uring 90 days provided that the storage temperature was-no higher than
12 degrees C: 75 degrees C for greater than or equal to 1,072 min, 80
degrees C for greater than or equal to 230 min, 85 degrees C for grea
ter than or equal to 36 min, and 90 degrees C for greater than or equa
l to 10 min. Following heating at 70 degrees C for 2,545 min and stora
ge at 12 degrees C, growth was first observed after 22 days. A factori
al experimental design allowed a predictive model to be developed that
described the incubation time required before the first sample showed
growth as a function of heating temperature (70 to 80 degrees C), per
iod of heat treatment (up to 2,545 min), and incubation temperature (5
to 25 degrees C). Predictions from the model provided a valid descrip
tion of the data used to generate the model, and agreed with observati
ons made previously.