SYNERGISTIC EFFECT OF HIGH-TEMPERATURE AND HIGH PH ON THE DESTRUCTIONOF SALMONELLA-ENTERITIDIS AND ESCHERICHIA-COLI O157-H7

This study was undertaken to determine if high temperature and high pH interact synergistically to enhance the rate of destruction of two im portant gram-negative foodborne pathogens, Escherichia coli O157:H7 an d Salmonella enteritidis. The rates of destruction in NaHCO3-NaOH buff ers at pH 7.0, 10.0, and 11.0 were determined at 35, 40, 45, 50, 55, 6 0, and 65 degrees C. Use of an improved heating protocol eliminated a ''tailing effect'' at longer exposure times. The present study demonst rated that the combination of high pH and high temperature resulted in a highly significant synergistic interaction (P > F = 0.0001), which caused rapid death of both E. coli O157:H7 and S. enteritidis. This '' alka-therm'' technology might be used commercially to destroy gram-neg ative foodborne pathogens on various raw agricultural commodities.