Dual-phasic Inactivation of Escherichia Coli O157:h7 with Peroxyacetic Acid, Acidic Electrolyzed Water and Chlorine on Cantaloupes and Fresh-cut Apples

The effects of peroxyacetic acid (POAA), acidic electrolyzed water (AEW) and chlorine on inactivation of Escherichia coli O157:H7 on fresh-cut apples and cantaloupe rinds were investigated. Apple cylinders were dipinoculated with E. coli O157:H7 and treated with sterilized water (control), chlorine, AEW or POAA for up to 8 min. Cantaloupe cylinders were spotinoculated with E. coli O157:H7 to the rind and treated with sterilized water, AEW or POAA for up to 15 min. All sanitizer treatments showed a significantly (P 0.05) higher inactivation than the control. The residual counts of E. coli O157:H7 on both fruits exhibited a dual-phasic reduction behavior, with a fast inactivation (D values: 0.8–5.0 min) in the first minute (phase I) of treatments followed by a much slower inactivation (D values: 14.6–59.8 min) in the remaining time (phase II). The dual-phasic inactivation seems to be related to fruit surface topography that determines the bacterial distribution.