Affiliation:
1. Department of Food Science, University of Wisconsin-Madison, Madison, Wisconsin 53706
Abstract
The practices of handling precooked chilled gravy in school kitchens were simulated to determine if they could contribute to outbreaks of foodborne illness. Time-temperature measurements and bacteriological tests were made at intervals during chilling, holding, and heating of gravy. Sixty-six pounds of cooked ground beef gravy were packed hot (158 F, 70 C) in bags, cooled in chilled water for 1 h, and refrigerated for 16 h. The gravy was held for 5 h at 82 F (28 C) and at 42 F (5.5 C) and then it was heated in a compartment steamer for 35 min. After 1 h cooling in chilled water, the mean temperature of gravy was 82 F (28 C) and after 16 h of refrigerated storage, the temperature was 45.5 F (7.5 C). The mean temperature of chilled gravy held at 82 F (28 C) remained about 50 F (10 C) for 4 h and reached 64 F (18 C) at the end of the 5-h holding period. The mean temperature of gravy held under refrigeration for 5 h decreased 2 F, from 45.5 F (7.5 C) to 43.5 F (6.5 C). After 35 min of heating in a compartment steamer, the highest temperature was 136 F (58 C) for gravy initially at 65 F (18.5 C) and 128 F (53.5 C) for gravy initially at 47 F (8.5 C). Bacteriological tests indicated that the greatest increase in the number of total aerobic bacteria in gravy occurred during cooling rather than holding. Although some samples yielded coagulase-positive staphylococci, the numbers changed little during holding or heating. Clostridium perfringens was not found in any samples of the gravy.
Publisher
International Association for Food Protection
Cited by
19 articles.
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