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

The efficacy of a new generation disinfectant, octenidine dihydrochloride (OH), as wash and coating treatments for reducing Listeria monocytogenes (LM), Salmonella spp. (SAL), and Escherichia coli O157:H7 (EC) on cantaloupe was investigated. Cantaloupe rind plugs inoculated separately with the three bacterial species (~8 log CFU/cm²) were washed for 1, 3, 5 min at 25 °C in water, or chlorine (200 ppm), ethanol (1%), OH (0.01, 0.05, 0.1%) and surviving populations were measured after treatment. Additionally, inoculated cantaloupe rind plugs were coated with 2% chitosan or chitosan containing OH (0.01, 0.05, 0.1%) and sampled for surviving pathogens. Subsequently, the antimicrobial efficacy of OH wash and coating (0.1, 0.2%) on whole cantaloupes was determined. All OH wash reduced LM, SAL, and EC on cantaloupe rinds by > 5 log CFU/cm² by 2 min, and reduced populations to undetectable levels (below 2 log CFU/cm²) by 5 min (P < 0.05). Similarly, OH coating on cantaloupe rinds reduced the pathogens by 3-5 log /cm² (P < 0.05). Washing and coating whole cantaloupes with OH reduced the three pathogens by at least 5 log and 2 log CFU/cm², respectively (P < 0.05). Results suggest that OH could be used as antimicrobial wash and coating to reduce LM, SAL, and EC on cantaloupes.