Inactivation of Bacteria S. aureus ATCC 25923 and S. Thyphimurium ATCC 14 028 Influence of UV-HPEF

Abstract

The research was objected to study the performance of the UV unit - HPEF in inactivating bacteria population of Gram-positive (S aureus ATCC 25923) and Gram-negative (S Thyphimurium ATCC 14028) inoculated in sterilized goat's milk. UV pasteurization instrument employed three reactors constructed in series UV-C system at 10 W, 253.7 nm wavelength made in Kada (USA) Inc. with 1.8 J/cm2 dose per reactor. HPEF instrument used high pulsed electric field at 31.67 kV/cm, 15 Hz and goat's milk rate at 4:32 ± 0.71 cc/second. Pathogenic bacteria was observed According to Indonesian National Standard 01-2782-1998. Inactivation rate of pathogenic bacteria ie S Thyphimurium ATCC 14028 and S. aureus ATCC 25923 was 0.28 and 0.19 log cycle or 6.35 and 4.34 log cfu/ml/hour, respectively; D value was 0.16 and 0.23 hour with k value was 14.62 and 10 hour-1 respectively.