Inactivation of inoculated Salmonella and natural microflora on two kinds of edible seeds by radio frequency heating combined with cinnamon oil vapor

Abstract

Sesame seed and flaxseed are oilseeds with many health benefits but with possible microbial contaminations, especially Salmonella, resulting in a potential health risk when consumed in raw form. In this study, plant essential oils (EOs) vapor, radio frequency (RF) heating and their combined treatments were applied to inactivate inoculated Salmonella and natural microflora on sesame seed and flaxseed. Cinnamon oil vapor and oregano oil vapor both at the concentration of 0.42–3.33 μL/mL treating for 7 d caused significant Salmonella reductions on these two kinds of seeds and cinnamon oil vapor had the better effect relatively. Weibull model was suitable to describe the thermal inactivation behaviors of Salmonella on edible seeds by RF heating. RF heating at 80 °C and 85 °C for 5 min combined with cinnamon oil vapor at 0.83 μL/mL for 3 d caused more than 5 log CFU/g reductions of Salmonella on sesame seed and flaxseed, respectively, but only 0.96 and 1.42 log CFU/g reductions of total bacterial counts, or 1.05 and 1.56 log CFU/g reductions of yeast and mold on sesame seed and flaxseed. Combined treatments did not cause damages on seeds’ quality. This study provides a new method for Salmonella inactivation on dry edible seeds.