Evaluation of Overhead Spray-Applied Sanitizers for the Reduction of Salmonella on Tomato Surfaces

Efficacy of sanitizers in an overhead spray and brush roller system was examined for reducing Salmonella on unwaxed, mature green tomatoes. Surface inoculated tomatoes were treated in the overhead spray system for 5, 15, 30, and 60 s. A sodium hypochlorite (NaOCl) study tested NaOCl (25, 50, and 100 mg/L) against a water control. A sanitizer study examined NaOCl (100 mg/L), chlorine dioxide (ClO2; 5 mg/L), peroxyacetic acid (PAA; 80 mg/L), and water. The overhead spray system was also compared to a scale-model flume. All NaOCl concentrations were significantly more effective at removing Salmonella than water and achieved at least a 3-log10 CFU/mL reduction at different treatment times (P < 0.05). NaOCl (100 mg/L) achieved a 4 +/- 1.8 log10 CFU/mL reduction at 15 s. In the sanitizer study, NaOCl, ClO2, and PAA achieved at least a 3-log10 CFU/mL reduction at 15 s and between 3.9 and 5.5 log10 CFU/mL reductions at 30 to 60 s. NaOCl (100 mg/L) in the overhead spray system significantly reduced more Salmonella than in the flume at 15 to 60 s. NaOCl flume treatment only reached a 1.3 +/- 1.1 log10 CFU/mL reduction at 15 s. Results of this study demonstrate the ability of sanitizers in the laboratory model overhead spray system to reduce Salmonella on tomato surfaces. An overhead spray system could be implemented instead of flumes to achieve higher pathogen reduction with less water and sanitizer use, thereby lowering packing costs.