Chlorine Inactivation of Escherichia coli O157:H7 in Fresh Produce Wash Process: Effectiveness and Modeling

Document Type

Article

Publication Date

10-16-2021

Publication Title

International Journal of Food Microbiology

Abstract

Inactivation rate constant or inactivation coefficient (specific lethality) quantifies the rate at which a chemical sanitizer inactivates a microorganism. This study presents a modified disinfection kinetics model to evaluate the potential effect of organic content on the chlorine inactivation coefficient of Escherichia coli O157:H7 in fresh produce wash processes. Results show a significant decrease in the bactericidal efficacy of free chlorine (FC) in the presence of organic load compared to its absence. While the chlorine inactivation coefficient of Escherichia coli O157:H7 is 70.39 ± 3.19 L/mg/min in the absence of organic content, it drops by 73% for a chemical oxygen demand (COD) level of 600–800 mg/L. Results also indicate that the initial chlorine concentration and bacterial load have no effect on the chlorine inactivation coefficient. A second-order chemical reaction model for FC decay, which utilizes a proportion of COD as an indicator of organic content in fresh produce wash was employed, yielding an apparent reaction rate of (9.45 ± 0.22) × 10−4 /μM/min. This model was validated by predicting FC concentration in multi-run continuous wash cycles with periodic replenishment of chlorine.

Comments

The authors acknowledge funding from the National Institute of Food and Agriculture Grant No. 2017-67018-26225.

Volume

356

Issue

16

DOI

10.1016/j.ijfoodmicro.2021.109364

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