Impact of pulsed electric fields technology on surface disinfection and quality properties of pistachios

Pistachios are contaminated with pathogenic and spoilage microorganism from harvesting to packaging resulting in quality degradation and safety issues. Disinfection of the pistachio by heat application provides reduction on microbial load, but it also causes undesirable changes in quality properties. Thus, processing of Antep pistachios by pulsed electric fields (PEF) with inactivation of microbial flora, and determination of changes on quality and sensory properties were studied. Application of 71.23 J/kg energy and 28.8 kV/cm electric field strength by continuous PEF system resulted in 4.73, 5.21, 5.56, and 4.87 log cfu/g reductions on Salmonella spp., total mesophilic aerobic bacteria, total mold and yeast, and total coliform bacteria, respectively. Although peroxide value, total fat content, total antioxidant capacity, total phenolic substance content, and total chlorophyl content were increased by applied energy (p <= 0.05), no significant difference was observed on color, total acidity, and sensory properties (p > 0.05). Concentration of fatty acids were changed by the applied treatments. Development of nonthermal treatments to process nuts with surface disinfetion and preservation of quality and sensory properties can ensure product safety and prevent product loss. PEF treatment providing inactivation of pathogenic and endogenous microbiota with preservation of quality properties brings an alternative to nut industry.