Staphylococcus aureus, Clostridium perfringens. Salmonella choleraesuis, and Salmonella typhimurium were inoculated (108 cells or spores) into two slow cookers containing green bean casserole, baked navy beans, chicken cacciatore, barbecued ribs or pork pot roast, and their fate determined after cooking. Heating patterns also were determined at three positions inside the two cookers. None of the foods cooked in either of the slow cookers contained detectable levels of S. aureus or salmonellae. The similarity between C. perfringens vegetative and spore counts indicate that only spores were present in the cooked foods. Except for the green bean casserole cooked using a low temperature setting, cooking resulted in a 0.44–1.67 and 0.36–1.54 log count reduction, respectively, of vegetative cells and spores of C. perfringens. Counts of vegetative cells and spores after cooking the green bean casserole were approximately .18 and .30 log counts higher than the uncooked counts. The mean times for the coldest areas in Cooker A to reach 50 C were 2.57 and 0.97 h, respectively, for the low (80 watts) and high (160 watts) temperature settings. The mean times for the coldest areas in Cooker B (removable liner) to reach 50 C were 2.35 and 0.52 h for the low (130 watts) and high (260 watts) temperature settings, respectively. Results suggest that when the recommended quantities of ingredients are used and the proper cooking procedure followed, foods prepared in the slow cookers studied do not present a health hazard.
On the chemical characteristics and dynamics of n-alkane low-temperature multistage diffusion flames
