Purpose: The purpose of this study was to determine the efficacy of a commercial wash solution for reducing pathogens in green leaf lettuce and tomatoes.
Methods: Lettuce (25 ± 0.3 g) and tomato (whole tomato) samples were inoculated with E. coli O157:H7 (~7.8 log CFU/ml) and Salmonella spp. (~9.39 log CFU/ml) cocktail inoculums, respectively, and then dried for 1 h. Inoculated samples were washed separately with commercial wash solution (contains citric acid and grapefruit oil) or tap water (control) for three contact times (30, 60, and 120 s). Lettuce (25 ± 0.3 g) and tomato (core of 11.34 cm2) samples were diluted and stomached for 1 min and then 0.1 ml was plated onto CT-SMAC and XLD agar plates for E. coli O157:H7 and Salmonella recovery. Experiment consisted of three replications and two samples per treatment (n = 6).
Results: Recovery of E. coli O157:H7 populations on leaf lettuce were different (P < 0.05) between commercial wash and tap water. For lettuce samples, E. coli O157:H7 reductions for 30, 60, and 120 s of commercial wash treatment were 3.12, 3.22, and 3.30 log CFU/g, respectively while, tap water resulted in ≥ 2.2 log CFU/g reductions. There were no differences (P > 0.05) between commercial wash and tap water in Salmonella populations recovered from tomatoes samples. For commercial wash treatments, Salmonella reductions on tomatoes were 2.13 log CFU/cm2 for all contact times whereas, tap water resulted in ≤ 2.0 log CFU/cm2 reductions.
Significance: Commercial wash solution reduced E. coli O157:H7 populations by > 3.0 logs on leaf lettuce and Salmonella populations by > 2.0 logs on tomatoes for all contact times. The commercial wash solution is applicable for food service and home-use and would reduce risk of pathogens on produce.