Effects of intense pulsed light on inactivation of Salmonella Typhimurium and quality characteristics of pecan halves

Abstract

Tree nuts have been associated with several foodborne outbreaks and recalls in the U.S. While thermal decontamination methods can inactivate pathogens, they come with challenges of varying severity on the product quality. Thus, this study evaluated the effects of nonthermal intense pulsed light (IPL) on Salmonella Typhimurium inactivation and quality attributes of pecan halves. The level of microbial reduction increased with an increase in treatment time from 10 to 40 s and decreased with an increase in the distance (8.28–13.36 cm) from the light source. Both treatments (time and distance) were found to have a significant effect (P ≤ 0.05) on microbial reduction, whereas interaction effects (time * distance) were not significant. A 3.43 log CFU/pecan reduction in Salmonella was achieved when samples were treated at 13.36 cm for 40 s. No significant difference in the color, texture, water activity, moisture content, and peroxide value was observed between control and IPL-treated samples. We observed a decrease in most monosaccharide sugar levels compared to untreated pecans. The SEM images showed changes in bacterial cell morphology in IPL treated samples. This study demonstrated that IPL treatment could be used as a potential decontamination method for pecan halves.