PERFORMANCE OF BACTERIAL SPORES IN A CARRIER SYSTEM IN MEASURING THE Fo‐VALUE DELIVERED TO CANS OF FOOD HEATED IN A STERITORT

Plastic rod biological indicator units (BIUs), filled with a suspension of Bacillus stearothermophilus spores and calibrated at 115.0, 121.1, and 127.0°C, were placed in 303 × 406 cans of corn and heated in a-Steritort at 115.6; 121.1, and 127.8°C. The BIUs were assayed for surviving spores. Biological F-values were determined from the calibration curves and Fo (BIO)-values calculated using appropriate z-value corrections. The Fo (BIO)-values for the same number of survivors per BIU but using calibration charts at different temperatures were compared and found to be in general agreement. Fo (PHY)-values were calculated using time-temperature data from thermocouple-equipped cans. The Fo (BIO)- and Fo (PHY)-values were compared. The results of this study indicate that BIUs can be used effectively to measure Fo-values' delivered to cans of food heated in continuous and/or agitating processing machines.