INACTIVATION OF STAPHYLOCOCCUS AUREUS IN ORANGE JUICE BY PULSED ELECTRIC FIELD TECHNOLOGY

Abstract

The inactivation of Staphylococcus aureus (S. aureus) in orange juice by pulsed electric field processing was experimentally investigated and compared with orange juice treated by thermal processing in this paper. The experiments were carried out by the total plate count method for the electric field strengths between 20 and 40 kV/cm and number of pulses between 10 and 50. In this study, the spectrophotometric colorimeter was used to evaluate the quality of orange juice.It was showed that both PEF and thermal treatments reduced the population of the S. aureus inoculated in orange juice. No viable cells were observed after thermal processing of orange juice whereas PEF treatment achieved 5 logarithmic cycle reductions of the microbial viability at the electric field strength up to 30 kV/cm and the pulse numbers of about 20 pulses. Finally, the CIE, DE, pH, Viscosity and TSS (oBrix) values of untreated orange juice (control) and orange juices treated by PEF and thermal processes was also not an important difference regarding quality.