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E. Y. TING, Avure Technologies Inc., Flow International Corp., 23500 64th Ave. S., Kent, WA 98032 A consortium of food companies is characterizing the inactivation kinetics of C. botulinum under High Hydrostatic Processing (HPP) conditions in order to demonstrate food safety for shelf-stable low acid foods. It is anticipated that HPP will lead to a new generation of higher sensory quality foods of enhanced value. This task necessitated the development of small scale testing equipment that fits into a Level 3 bio hazard area and testing methods to minimize the effect of adiabatic heating due to pressurization. Thermodynamic induced temperature change observed during HPP is unavoidable during pressure change. In a small test system, the ease of heat transfer can result in rapid temperature changes during constant pressure holding. This can result in conditions where the temperature is changing throughout the pressure hold period. The method developed here utilizes a balance between heat loss and heat grain during testing. The end result is a minimized temperature gradient between the compression heated sample and the non-compression heated pressure vessel environment. This results in a temperature history during pressure hold that is less subject to temperature change. This testing method requires the predetermination of sample and test chamber temperatures, and the synchronization of sample loading and pressurization rate. When optimally performed, near constant pressure, constant temperature sample histories can be achieved.
Session 9, Mechanisms and modeling of bacterial spore inactivation by high pressure processing
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |