Spray Washing of Tomatoes with Chlorine Dioxide To Minimize Salmonella on Inoculated Fruit Surfaces and Cross-Contamination from Revolving Brushes

Abstract

Chlorine dioxide (ClO(2)) is an antimicrobial agent available for commercial produce washing. This study examined the efficacy of ClO(2) at 5 parts per million (ppm) during spray washing of tomatoes (5.0 ml/s per fruit) for preventing Salmonella enterica transfer from inoculated roller brushes to fruit and wash runoff. Furthermore, the sanitizing effects of ClO(2) during spray washing at low and high flow rates (5.0 and 9.3 ml/s per fruit, respectively) on tomato surfaces (nonstem scar areas) with either newly introduced (wet) or overnight air-dried Salmonella inocula were investigated. Salmonella transfer from contaminated brushes to fruit surfaces was reduced 2.1 +/- 0.6 or 4.7 +/- 0.2 log cycles after spray washing with water for 40 s or with the ClO(2) solution for 10 s, respectively. Cross-contamination of Salmonella from brushes to wash runoff during fruit washing for 60 s decreased 5.9 +/- 0.3 log cycles when ClO(2) was used. Fruit washing using contaminated brushes and low flow-rate washing with either water or ClO(2) solution for 10 s reduced newly introduced Salmonella on fruit surfaces by 1.7 +/- 0.6 or 5.1 +/- 0.3 log cycles, respectively. For fruit surfaces with air-dried inocula, washing with water and using uncontaminated brushes for 10 to 40 s reduced Salmonella by 3.2 +/- 0.3 to 3.4 +/- 0.4 log cycles; and the reduction was significantly improved by using ClO(2), high flow rate, or a longer washing time. Washing with ClO(2) at tested flow rates for 10 to 60 s resulted in a 4.4 +/- 0.6 to 5.2 +/- 0.1 log reduction of air-dried Salmonella on fruit surfaces.

Chlorine dioxide and chlorine effectiveness to prevent Escherichia coli O157:H7 and Salmonella cross-contamination on fresh-cut Red Chard

“…Typhimurium from inoculated Red Chard leaves to processing water as affected by sanitizer and washing types. inoculum level, ClO 2 concentration, contact times, washing conditions and recovery procedures (Lee & Baek, 2008;Pao, Kelsey, Khalid, & Ettinger, 2007, Pao, Kelsey, & Long, 2009Singh, Singh, & Bhunia, 2003;Singh, Singh, Bhunia, & Stroshine, 2002). Washing iceberg lettuce for 2 min with TriNova (20, 100 and 200 mg/L of ionic ClO 2 À ) resulted in reductions of E. coli O157:H7 of 0.96, 1.05 and 1.13 log CFU/g respectively (Keskinen et al, 2009).…”

Cross-contamination and recontamination by Salmonella in foods: A review

“…Washing procedure is one of the most studied measures to reduce the level of contamination. Pao, Kelsey, and Long (2009) examined the efficacy of chlorine dioxide during spray washing of tomatoes for preventing Salmonella enterica transfer from inoculated roller brushes to fruit and wash runoff, reporting an important reduction of the pathogen (5.0 ± 0.3 log). Rana et al (2010) designed a washing system of tomatoes to simulate a commercial postharvest washing, showing that the use of higher temperatures (37°C) during washing lead to lower Salmonella uptakes than those observed at 20°C.…”

Efficacy of Chlorine, Chlorine Dioxide, and Peroxyacetic Acid in Reducing Salmonella Contamination in Wash Water and on Mangoes Under Simulated Mango Packinghouse Washing Operations

“…Similar to chlorine, chlorine dioxide also oxidizes organic matter eventually leading to a reduction in its effective concentration and antimicrobial activity (Goodburn and Wallace, 2013). When employed as a wash water disinfectant, chlorine dioxide has been applied at 5 ppm in water to keep the residue concentration on washed produce within the approved 3-ppm limit [US Food Drug Administration (USFDA) and Center for Food Safety Applied Nutrition, 1998;Pao et al, 2009;21 CFR 173.300]. Peroxyacetic acid (PAA) has been shown to be effective against foodborne pathogens on different produce surfaces (Hilgren et al, 2007;Vandekinderen et al, 2009).…”