ABSTRACT
A model was developed for adjusting the minimum public health sterilization F-value of foods with pH values from 4.6 to 6.0 based on the Clostridium botulinum spore heat resistance data of Xezones and Hutchings (6). Starting with the maximum pH of the product, this model was used to calculate the F250°F-value equivalent to an F250°F-value of 3.0 min. The model yielded an F250°F-value of 2.0 min when the pH was 5.3 and 1.2 min when the pH was 4.6.
ABSTRACT
The bactericidal and sporicidal effects of halogens are reviewed. Chlorine and iodine are the halogens most widely used for inactivating microorganisms. Compounds containing chlorine and iodine are, in general, equally effective in destroying vegetative cells, but chlorine compounds are more effective in inactivating spores. These relationships are illustrated graphically from the data available in the literature.
ABSTRACT
Outbreaks of botulism involving acid foods are rare. Of the 722 total botulism outbreaks reported from 1899 to 1975, only 34 (4.7%) involved acid foods. Home-canned acid foods were implicated in 34 of the 35 acid food outbreaks. Clostridium botulinum cannot grow at a pH of ⩽ 4.6; therefore, for a botulism hazard to exist in an acid food, a contamination with other microorganisms due to a process delivery failure and/or post-process contamination, (c) favorable composition of the food and storage conditions which are particularly conducive to C. botulinum growth and toxin production, and (d) metabiosis. The way each factor affects the botulism hazard in acid foods is discussed in this report. An acid food is safe from C. botulinum if the heat process kills all organisms capable of growth at a pH of ⩽4.6 and there is no post-process contamination.
ABSTRACT
The heat resistance of ten Clostridium botulinum type B spore crops was determined in mushroom puree and 0.067M Sorenson phosphate buffer (pH 7). The spore crops were grown from Clostridium botulinum isolates obtained from commercially canned mushrooms. The D-values for all of the C. botulinum spore crops were overall slightly higher in the buffer than in mushroom puree. The mean D(110.0 C)-value for the ten spore crops in buffer was 1.17 min and for the spores in mushroom puree the mean D(110.0 C)-value was 0.78 min. The mean D(115.6 C)-value in buffer for the ten spore crops was 0.24 min compared to a mean D(115.6 C)-value of 0.19 min for spores in mushroom puree. The C. botulinum type B spores tested in this study had a heat resistance that was less than the classical heat resistance for C. botulinum spores.
