Sanitation Interventions for Reducing Listeria monocytogenes and Salmonella on Canvas and Cordura® Harvest Bags.

Abstract

Food contact surfaces, including harvest bags, are potential vectors for cross-contamination in produce operations, yet recommendations for their sanitation are limited. This study evaluated the efficacy of wet- and dry-based sanitizers in reducing Listeria monocytogenes and Salmonella on two harvest bag materials, canvas, and Cordura®. Coupons (25cm²) were inoculated with 5-strain cocktails of L. monocytogenes or Salmonella (∼7 log CFU/coupon) before treatment. Treatments included chlorine (200 ppm; pH 7), peroxyacetic acid (PAA; 200 ppm), isopropyl alcohol with quaternary ammonium compounds (IPAQuats; ready-to-use), steam, and water. Sanitizers were applied according to the manufacturer's instructions for a 1-minute contact time. After treatment, pathogen concentrations were enumerated on selective (Modified Oxford, Xylose Lysine Deoxycholate) and non-selective (Tryptic Soy Agar) media. Duplicate experiments were conducted with five replicates per treatment (n=10) and pathogen reductions were evaluated using log-linear mixed-effects models. IPAQuats observed the highest reductions with L. monocytogenes reductions of 5.16±0.93 log CFU/coupon and 6.01±0.49 log CFU/coupon, and Salmonella reductions of 4.61 ± 1.03 log CFU/coupon and 5.90 ± 0.57 log CFU/coupon on canvas and Cordura®, respectively. PAA resulted in L. monocytogenes reductions of 2.63±0.56 and 3.92±0.81 log CFU/coupon and Salmonella reductions of 3.68±0.79 and 3.21±1.14 log CFU/coupon on canvas and Cordura®, respectively. Chlorine and steam were less effective with reductions of <3 log CFU/coupon for both pathogens and materials. While no difference in L. monocytogenes reduction was observed between materials by treatment, Salmonella reductions on Cordura® were significantly higher than reductions on canvas after treatments with IPAQuats (1.62 log CFU/coupon; 95% CI=1.19, 2.05) and steam (0.84 log CFU/coupon; 95% CI=0.42, 1.28). Results provide recommendations for produce growers on effective sanitation of harvest bags.