46B-7 |
Heat penetration studies of stewed tomatoes in 6, 8, and 17 quart household pressure retorts |
R. J. PAKOLA and E. L. Andress. Department of Foods and Nutrition, University of Georgia, 208 Hoke Smith Annex, Athens, GA 30602-4356 Most current home pressure canning recommendations were developed using standard 17 to 21 quart pressure retorts. Today’s marketplace offers a variety of smaller pressure-based cookers/canners. Retort size has the potential to affect come up and cooling rates, which contribute to the sterilizing value of a pressure process. As heating and cooling times are reduced so is total lethality. The objective of this study was to compare fh values, cumulative lethalities, and potential safe process times during pressure processing of stewed tomatoes in 6, 8, and 17 quart household pressure retorts. Stewed tomatoes were prepared and packed into 8 oz glass home canning jars. Jars were processed at 121.1 degrees C for 25 minutes in 6, 8, and 17 quart pressure retorts after a 10 minute venting of the retort. Heat penetration data were collected at the cold spot, previously determined to be the geometric center of the jar. Continuous temperature profiles from 15 replications were collected using copper-constantan needle thermocouples connected to an electronic data logger. Potential process times and cumulative lethal rates were calculated for the destruction of Clostridium botulinum spores. Differences in fh values were not significant indicating that retort size does not affect the rate of heating during the process period. Lower initial product temperatures resulted in lower cumulative lethalities. Greater lethality was accumulated in the 8 versus 6 quart retort. Calculated potential process times supported that the 6 quart retort would require a longer process than the 8 quart to achieve an equivalent total lethality. Current process recommendations intended for standard size canners may not be sufficient in very small pressure retorts. Home canning in very small retorts should be avoided until safe process recommendations can be determined. Initial product temperatures need to be examined in the development of home canning recommendations.
Session 46B, Extension
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