Inactivation of Escherichia coli O157 : H7 and Escherichia coli 8739 in apple juice by pulsed electric fields

The effect of high voltage pulsed electric held (PEF) treatment on Escheric hia coli O157:H7 and generic E. coli 8739 in apple juice was investigated. Fresh apple juice samples inoculated with E. coli O157:H7 and E. coli 8739 were treated by PEF with selected parameters including electric field stren gth, treatment time, and treatment temperature. Samples were exposed to bip olar pulses with electric field strengths of 30, 26, 22, and 18 kV/cm and t otal treatment times of 172, 144, 115, and 86 mu s. A 5-log reduction in bo th cultures was determined by a standard nonselective medium spread plate l aboratory procedure. Treatment temperature was kept below 35 degrees C. Res ults showed no difference in the sensitivities of E. coli O157:H7 and E. co li 8739 against PEF treatment. PEF is a promising technology for the inacti vation off. coli O157:H7 and E. coli 8739 in apple juice.