Purpose: Determine survival and transfer of Salmonella onto netted and unnetted cantaloupe varieties in a post-harvest wash scenario.
Methods: To evaluate chlorine post-harvest wash efficacy, a commercially available netted variety and an experimental unnetted variety of cantaloupe (n = 12) were inoculated with 100 μl of a cocktail of five prominent Salmonella serotypes resistant to 50 ppm nalidixic acid and dried. Nine fruit were immersed in 100 ppm free chlorine for two minutes, while three served as no wash controls. Each cantaloupe was rinsed with phosphate buffer saline (PBS) with 0.2% Tween 80. Remaining Salmonella populations were enumerated onto Tryptic Soy Agar with Nalidixic Acid (TSAN). Additionally, nine cantaloupes of each variety were placed in ten liters of water containing 107 CFU/ml of Salmonella cocktail for two minutes each, simulating a contaminated dump tank. After rinsing with PBS with 0.2% Tween 80, Salmonella populations were enumerated on TSAN.
Results: Surviving populations of Salmonella on netted and unnetted cantaloupe, when exposed to 100 ppm free chlorine were, 6.83 and 4.24 log CFU/cantaloupe, respectively (P < 0.05). The lack of netting had a significant effect on the efficacy of the chlorine treatment (P < 0.05), resulting in a 1.83 and 4.08 log reduction on netted and unnetted surfaces. When evaluating transfer by contaminated water, unnetted melons had an average of 5.42 log CFU/cantaloupe and netted averaged 6.17 log CFU/cantaloupe, but these populations were not significantly different (P > 0.05).
Significance: Chlorine treatment of contaminated unnetted cantaloupe was significantly more effective than that of netted cantaloupe. However, there was no difference in populations transferred to netted and unnetted cantaloupe when immersed in contaminated water. Further studies with unnetted cantaloupe varieties should be undertaken to better understand advantages over netted varieties with respect to food safety.