Inactivation of Listeria monocytogenes, Salmonella spp. and Escherichia coli O157:H7 on cantaloupes by octenidine hydrochloride

Authors: UPADHYAY, ABHINAV - University Of Connecticut; CHEN, CHI-HUNG - University Of Connecticut; YIN, HSINBAI - University Of Connecticut; UPADHYAY, INDU - University Of Connecticut; FANCHER, SAMANTHA - University Of Connecticut; LIU, YAN YAN - University Of Connecticut; NAIR, MEERA - University Of Connecticut; JANKELUNAS, LEANNE - University Of Connecticut; Patel, Jitu; VENKITANARAYANAN, KUMAR - University Of Connecticut

Submitted to: Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2016
Publication Date: 5/3/2016
Publication URL: https://handle.nal.usda.gov/10113/5263671
Citation: Upadhyay, A., Chen, C., Yin, H., Upadhyay, I., Fancher, S., Liu, Y., Nair, M., Jankelunas, L., Patel, J.R., Venkitanarayanan, K. 2016. Inactivation of Listeria monocytogenes, Salmonella spp. and Escherichia coli O157:H7 on cantaloupes by octenidine hydrochloride. Food Microbiology. 58(9):121-127.

Interpretive Summary: Multi-state disease outbreaks due to consumption of cantaloupes contaminated with Salmonella and Listeria monocytogenes have been reported in the U.S. Current industrial practice of cantaloupe wash with chlorine results in minimal reductions in pathogen populations. We investigated the efficacy of a new generation disinfectant, namely octenidine dihydrochloride (OH) as wash and coating treatments for reducing disease causing bacteria on cantaloupe surface. All OH wash treatments reduced L. monocytogenes, Salmonella spp. and E. coli O157:H7 on cantaloupe rinds greater than 100,000-fold per cm2 in 2 min. The chitosan-based coating of OH on cantaloupe rinds reduced the pathogens by 1000 to 100,000-fold. Washing whole cantaloupes for 5 min with 0.1 and 0.2% OH decreased pathogen populations by at 100,000-fold per cm2. These data show that OH could be effectively used for wash and coating treatments to reduce L. monocytogenes, E. coli O157:H7, and Salmonella spp. on cantaloupes and enhance food safety. This information should be useful to other scientists, the produce industry and regulatory agencies.

Technical Abstract: This study investigated the efficacy of a new generation disinfectant, namely octenidine dihydrochloride (OH) as wash and coating treatments for reducing Listeria monocytogenes, Salmonella spp., and Escherichia coli O157:H7 on cantaloupe surface. Cantaloupe rind plugs inoculated separately with L. monocytogenes, Salmonella spp., or E. coli O157:H7 (~8 log/cm2) were washed for 1, 3, or 5 min at 25°C in sterile water (control), chlorine (200 ppm), ethanol (1%) (diluent for OH) or water containing OH (0.01, 0.05, 0.1%), and surviving pathogen populations were enumerated. Additionally, inoculated cantaloupe rind plugs were coated with 2% chitosan or chitosan containing OH (0.01, 0.05, 0.1%) and sampled for surviving pathogen populations. Subsequently, the efficacy of OH wash and coating treatments (0.1 and 0.2%) in inactivating the three pathogens on whole cantaloupes was determined. All OH wash treatments reduced L. monocytogenes, Salmonella spp. and E. coli O157:H7 on cantaloupe rinds by > 5 log CFU/cm2 by 2 min, and decreased their counts to undetectable levels (below 2 log CFU/cm2) by 5 min (P < 0.05). Cantaloupe washing in deionized water, 200 ppm chlorine, or 1% ethanol for 5 min reduced pathogen counts by less than 1 log CFU/cm2. Similarly, OH coating on cantaloupe rinds reduced the pathogens counts by 3 to 5 log CFU/cm2 (P < 0.05). Washing whole cantaloupes for 5 min with 0.1 and 0.2% OH decreased pathogen populations by at least 5 log CFU/cm2 (P < 0.05). Moreover, chitosan-based OH coating at 0.1 and 0.2% decreased all three pathogen populations on whole cantaloupes (P < 0.05). Results indicate that OH could be effectively used as wash and coating treatments to reduce L. monocytogenes, E. coli O157:H7, and Salmonella spp. on cantaloupes and enhance food safety.