The safety of a home-style canned quick bread was investigated using spores of Clostridium sporogenes putrefactive anaerobe (PA) 3679. Baking was done at 177°C for 30, 40 and 50 min, at 191°C for 45, 50 and 55 min, and at 204°C for 40, 45 and 50 min. Products were analyzed for pH, water activity (aw) and vacuum level. The microbial quality of the products was determined before and after baking. Of the products baked at 177°C, some were stored for 90 days at room temperature (23 to 25°C) or in an incubator at 35°C to study their shelf-life. Inoculated and endogenous vegetative cells and their spores were counted before and after baking and after storage using Fung's Double Tube method. Results showed germination of endogenous spores in uninoculated products after baking at 177°C for 30 min and storage at 35°C for 90 days. Survival of inoculated C. sporogenes PA 3679 was detected for all baking and storage treatments. Further work is recommended to determine safe processing procedures for this type of product.
Contribution No. 93-30-J, Kansas Agricultural Experiment Station, Manhattan, Kansas.