Design, construction, and evaluation of a sanitary pilot plant system pulsed electric field

A sanitary fluid-handling system has been designed and constructed for the treatment of fluid and particulate (up to 1/8 in.) food products in an integrated pilot plant scale pulsed electric field (PEF) processing and aseptic packaging system. The system offers flexibility of processing parameters to explore the synergistic effects of heat and PEF to produce an extended-shelf-life product. The key parameters for this fluid-handling system are that it is capable of being sterilized; the product flow rate is constant, pulseless, and with minimal shear; and thermal and electrical treatment parameters are monitored. The system components were selected to meet 3-A standards and allow for clean-in-place (CIP) sanitation. An operational manual was developed for the safe and efficient operation of this pilot plant system. For evaluation purposes, single-strength orange juice was treated with PEF in this pilot plant system to optimize PEF processing conditions for maximum inactivation microorganisms and pectin methyl esterase (PME). Electric field strengths of 20, 25, 30, and 35 kV/cm and total treatment times of 39, 49, and 59 mus were tested. The higher electric field strength and the longer total treatment time were more effective in inactivation. PEF treatment of orange juice at 35 kV/cm for 59 mus caused 7 log reduction in the total aerobic plate counts and the yeast and mold counts. A reduction of 90% PME activity was achieved by this PEF processing condition. This PEF treatment also prevented the growth of microorganisms and the recovery of PME activity at 4, 22, and 37degreesC for 16 weeks.