Purpose: This study aimed to assess the efficacy of four sanitizers against Salmonella on a custom dual belt conveyor system during conveyance of diced tomatoes.
Methods: Four kg of diced tomatoes containing avirulent Salmonella Typhimurium LT2 (107 CFU/g) were placed in an inoculation tray through which an interlocking and smooth belt (Intralox, Harahan, LA) were passed for 5 min for uniform inoculation. Five treatments - 80 ppm peroxyacetic acid (Tsunami 100, Ecolab), 80 ppm mixed peracid (Tsunami 200, Ecolab), 80 ppm chlorine at pH 6.0 (XY-12, Ecolab), 80 ppm chlorine in electrolyzed water at pH 3.0, and water (control) were continuously sprayed onto both belts (30 l/h) for 20 min. Before and after spraying, Kimwipe samples collected from selected surfaces of the conveyor belts were stomached in neutralizing buffer for 1 min and then surface-plated on trypticase soy agar containing 0.6% yeast extract, 0.05% ferric ammonium citrate and 0.03% sodium thiosulfate with/without 0.45 μm membrane filtration to quantify Salmonella.
Results: For the smooth and interlocking belts, Salmonella reductions were greater (P < 0.05) using mixed peracid (6.49 and 6.76 log) and peroxyacetic acid (5.95 and 6.10 log) as compared to chlorine at pH 6.0 (3.72 and 5.70 log) and electrolyzed water (3.50 and 4.53 log) with water alone decreasing populations 1.52 and 1.48 logs, respectively. Log reductions were similar for the smooth an interlocking belts (P > 0.05), except for chlorine at pH 6.0 which was more efficacious for the interlocking belt.
Significance: Spray application of sanitizers is an effective means to reduce microbial cross-contamination during conveyance of diced tomato with electrolyzed water being particularly attractive due to its low cost and ease of preparation.