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The objective of this project is to develop methods for the prediction of microbial lethality during PEF processing. At present there are no means of predicting microbial lethality in a PEF process.
The fact that different implementations of PEF technology result in different lethality to the same microorganism indicates a lack of sufficient understanding of the basic effect of PEF on microorganisms--an understanding that is vital if PEF is to be commercialized. The project has progressed according to plans. After receiving the pulsing unit, it was modified to allow precise control over pulse duration and time between pulses. A static chamber was designed and submitted for fabrication as a prototype. It was adequate. A gel was found and used in several preliminary treatments with E. coli O157:H7 and Listeria monocytogenes. These experimental runs gave a consistent 3 log reduction for 10 pulses at constant temperature for E. coli O157:H7 and a one log reduction for Listeria monocytogenes. The nonuniform field tests were not undertaken. Limitations with the pulsing unit did not allow a large enough sample volume to allow testing for field uniformity.