Effect of sanitizing treatments on removal of bacteria from cantaloupe surface, and re-contamination with Salmonella

There are many reports of disease due to consumption of cantaloupes contaminated at the surface with enteric pathogens. Salmonella is among the most frequently reported cause of foodborne outbreaks of gastroenteritis in the United States. Research was undertaken to determine the effects of sanitizer and hot water treatments on microbial populations on cantaloupe surfaces and to determine whether prior decontamination of melons by sanitizer treatment affects vulnerability to recontamination by Salmonella. Cantaloupes were sanitized with 200 ppm chlorine or 2.5% hydrogen peroxide solution for 2 min, or hot water (96 °C) for 2 min and were held at 5 °C for 24 h. Hot water treatments reduced the microbial populations on cantaloupe surface by 4.9 log reduction while H2O2 or chlorine caused approximately 2.6 log unit reduction on cantaloupe surfaces. When sanitized or hot water treated whole cantaloupes were re-inoculated with Salmonella. Higher populations of Salmonella were recovered from sanitized cantaloupes than from the untreated controls; recovery was greater from hot water treated cantaloupes than from cantaloupes treated with chlorine or hydrogen peroxide. The results of this study clearly show that sanitized cantaloupes are susceptible to recontamination if exposed to a human bacterial pathogen during subsequent handling.