M. E. A. Mohammed^{1, 2,}, A. H. Amer Eissa², S. M. Aleid³

Pulsed electric field (PEF) processing of liquid and semisolid food is a nonthermal technology alternative to traditional thermal preservation method with preserving nutritional and sensory values of food. In this study, the components of a laboratory scale prototype of PEF system were designed and constructed. Evaluating the performance of the prototype was carried out to inactivate the existing microorganisms (mesophilic aerobic bacteria, Yeasts and Molds) in semi-solid pitted date palm fruits, which was defined in terms of applied intensity of electric field and pulses number at a constant duration of pulse (40 µs) and (1 Hz) pulse frequency. The microbial count was decreased with the increase in intensity of electric field and pulses number. The electric field intensity of 10.82 kV/cm and 120 pulses lead to reduced total microbial counts of 1.18×10⁴ cfu/g to less than 10 cfu/g of mesophilic aerobic bacteria in most treated samples. The electric field intensity of 8.84 kV/cm and 90 pulses lead to reduce total microbial counts of 3.27×10³ cfu/g of yeasts and molds to less than 10 cfu/g that meet Saudi standards requirements. Non-detectable levels of yeasts and molds in most treated samples were observed when 10.82 kV/cm of electric field intensity and 60 of pulses number were applied. The current results indicated that PEF technology is promising as a non-thermal method for inactivation of microorganisms on date palm fruits processing.

pulsed electric field, date palm fruits, microbial contamination, preservation, non-thermal technology