The microbial safety and the shelf-life of various vacuum cooked foods were evaluated, in industrial situations the raw material features and size of the products have a wide variability with respect to the rate of thermal increase, pasteurization value and cooling rate. Surviving microorganisms mainly belong to the genus Bacillus (Bacillus stearothermophilus, B. subtilis, B. pumilus, B. polymyxa, B. sphaericus). Bacillus cereus and Clostridium perfringens were not detected in this study. The shelf-life of the various products, predicted on the basis of a storage test at 4 degrees C, ranged from 40 to 76 days. Thermal abuse at 15 degrees C remarkably decreased the shelf-life and allowed the growth of anaerobic sporeforming bacteria. Challenge testing using a mixture of spores of Bacillus cereus, Bacillus licheniformis and Clostridium perfringens showed that only B. licheniformis was able to survive during storage at temperatures less than or equal to 4 degrees C in ail samples. B. cereus proved to have a growth potential only when inoculated in pilaf rice and under abuse conditions, while the viability of C. perfringens continued to decrease during refrigerated storage.[...]
Evaluation of the safety prediction of the shelf life of vacuum cooked foods
CHAVES LOPEZ, CLEMENCIA;
1997-01-01
Abstract
The microbial safety and the shelf-life of various vacuum cooked foods were evaluated, in industrial situations the raw material features and size of the products have a wide variability with respect to the rate of thermal increase, pasteurization value and cooling rate. Surviving microorganisms mainly belong to the genus Bacillus (Bacillus stearothermophilus, B. subtilis, B. pumilus, B. polymyxa, B. sphaericus). Bacillus cereus and Clostridium perfringens were not detected in this study. The shelf-life of the various products, predicted on the basis of a storage test at 4 degrees C, ranged from 40 to 76 days. Thermal abuse at 15 degrees C remarkably decreased the shelf-life and allowed the growth of anaerobic sporeforming bacteria. Challenge testing using a mixture of spores of Bacillus cereus, Bacillus licheniformis and Clostridium perfringens showed that only B. licheniformis was able to survive during storage at temperatures less than or equal to 4 degrees C in ail samples. B. cereus proved to have a growth potential only when inoculated in pilaf rice and under abuse conditions, while the viability of C. perfringens continued to decrease during refrigerated storage.[...]I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
