Summary of Awards to Date

Impact of wash water disinfectants on Salmonella enterica transfer and survival in mango packing facility water tank operations

Date

Jan. 1, 2015 - Dec. 31, 2016

Funding Agency

Center for Produce Safety

Amount Awarded

$142,166.00

Investigator

Mary Anne Amalaradjou, Ph.D.
University of Connecticut

Summary

Foodborne outbreaks associated with consumption of raw mangoes have been traced back to the use of contaminated wash water. This highlights the critical role of wash water disinfection in mango processing, affecting its quality, and safety. While investigations on the efficacy of disinfectants to reduce pathogens on other fruits have been performed, no studies have been conducted on mangoes. Therefore, this study will investigate the efficacy of different disinfectants (chlorine, peracetic acid and FIT fruit and vegetable wash solutions) for killing Salmonella on mangoes and prevention of water–to-mango cross contamination. The study will be performed under conditions that simulate dump tank washing, hot water treatment and hydrocooling. Additionally, the study will investigate the efficacy of trans-cinnamaldehyde, a GRAS status antimicrobial for use as a natural, alternative disinfectant in mango wash water. It is expected that this study will provide insight into the efficacy of disinfectants to inactivate Salmonella in mango packing facility water operations. Furthermore, this proposal will help understand the role of organic load in mango wash water on disinfectant efficacy. In conclusion, the proposed research is expected to help develop best practices regarding post-harvest washing and disinfection of mangoes to control Salmonella and other potentially pathogenic organisms.

Technical Abstract

Mangoes have been associated with foodborne outbreaks involving different serovars of Salmonella, including S. Oranienburg (1998), S. Newport (1999) and S. Saintpaul (2001 and 2003). A common theme in these outbreaks was the source of contamination which was traced back to wash water used in hydrocooling. In order to reduce mango flesh temperature following hot water treatment, mango producers practice hydrocooling.  However, it has been shown that cooling of fruit following heat treatment can lead to potential pathogen internalization into mangoes. Since there are no available technologies to inactivate internalized pathogens, wash water disinfection is a critical processing step in mango production, affecting its quality, safety and shelf-life. Although several commercially available chemical disinfectants are approved for use in wash water, chlorine is the most commonly used chemical sanitizer in the fresh produce industry. Besides chlorine, other commercially used wash solutions include peracetic acid based disinfectants and natural alternatives such as FIT vegetable and fruit wash. Although investigations on the efficacy of disinfectants to reduce pathogens on other fruits such as cantaloupe, berries, and apples have been performed, no studies have been conducted on mangoes.  Additionally, most studies have not examined the effect of organic matter on the antimicrobial efficacy of disinfectants. Furthermore, there are several unique differences in the post-harvest management practices for mangoes when compared to other fruits. Therefore, these reasons warrant the need for an investigation into the efficacy of different disinfectants on pathogen inactivation on mangoes and in mango wash water operations.  Hence this study will be undertaken to evaluate the antimicrobial activity of water disinfectants on pathogen inactivation in presence and absence of organic matter. In order to simulate the mango packing facility water tank operations, the effect of disinfectants on Salmonella transfer from water-to-mango and its control on mango surface will be done in three different stages to mimic washing in the dump tank, hot water treatment and hydrocooling. Additionally, the study will also investigate the efficacy of trans-cinnamaldehyde, a GRAS status antimicrobial for use as a wash water disinfectant in the mango industry. Trans-cinnamaldehyde was selected as a potential candidate based on its antimicrobial effect on other produce as established in scientific literature. Through these objectives, the proposed research will provide insight into the efficacy of disinfectants for pathogen inactivation during mango washing operations and the role of organic matter on disinfectant effectiveness.  This in turn will help develop best management practices regarding post-harvest washing of mangoes and yield potential water disinfection treatments for application in the mango industry.