High intensity pulsed electric fields applied to egg white: Effect of Salmonella enteritidis inactivation and protein denaturation

High-intensity electric fields have been successfully applied to the destru ction of Salmonella Enteritidis in diaultrafiltered egg white. The effects of electric field strength (from 20 to 35 kV cm(-1)), pulse frequency (from 100 to 900 Hz), pulse number (from 2 to 8), temperature (from 4 to 30 degr ees C), pH (from 7 to 9), and inoculum size (from 10(3) to 10(7) CFU . ml(- 1)) were tested through a multifactorial experimental design. Experimental results indicate that, for Salmonella inactivation, the electric field inte nsity is the dominant factor with a strongly positive effect, strengthened by its positive interaction with pulse number. Pulse number, temperature, a nd pH have also significant positive effects but to a lesser extent. In the most efficient conditions, the pulsed electric field (PEF) treatment is ca pable of 3.5 log(10) reduction in viable salmonellae. Simultaneously, the m easure of surface hydrophobicity does not indicate any increase after PEF t reatment. These results suggest that no protein denaturation occurs, unlike what is observed after comparable heat treatment in terms of Salmonella in activation (55 degrees C for 15 min).