Survival and attachment of Listeria monocytogenes on bell peppers and influence of attachment time on efficacy of chlorine

Abstract

Strong bacterial attachment or biofilm formation on produce surfaces may result in limited penetration ability of sanitizers. This study evaluated the effect of the attachment level of Listeria monocytogenes during storage on the efficacy of chlorine treatment on bell pepper surfaces. Bell peppers inoculated with L. monocytogenes were stored at 4 °C and 25 °C, and attachment strength (SR) and the efficacy of chlorine were examined during storage. The L. monocytogenes population at 4 °C decreased significantly from 6.41 log CFU/g at 1 h to 4.25 log CFU/g at 72 h while remaining constant at all times at 25 °C (6.41 log CFU/g at 1 h to 5.72 log CFU/g at 72 h). The SR value of bacteria at 4 °C remained constant throughout the storage while at 25 °C it remained similar until 48 h and increased significantly at 72 h (0.72). Chlorine washing significantly reduced the bacterial level in the samples stored for 1 h and all the samples stored at 25 °C as compared to washing with water. The survival and attachment of bacterial cells were found to be significantly (P < 0.05) better at 25 °C than at 4 °C. Efficacy of chlorine was affected by the attachment of bacteria.