Purpose: This study simulated processing in a retail setting to evaluate efficacy of water, electrolyzed water (EOW), and a commercial acid sanitizer (AS) in prevention of cross-contamination.
Methods: A whole cantaloupe was dip-inoculated with a cocktail of Salmonella or L. monocytogenes to achieve approximately 5 log CFU/cm2. One inoculated and two non-inoculated cantaloupes were treated in 76 L of tap water, EOW (free chlorine: 50 to 60 ppm), and AS (pH≈2.8, combination of lactic acid and phosphoric acid) for 5 min. Subsequently fresh-cut cubes of flesh from inoculated and non-inoculated cantaloupe were soaked in water, EOW, or AS for 90 s. Microbiological analysis was conducted to determine possible cross-contamination during a processing.
Results: EOW treatment resulted in approximately 1.5-log reduction both in Salmonella and L. monocytogenes inoculated on the rind of whole cantaloupe, which was significantly higher than tap water treatment (P<0.05). Cross-contamination of non-inoculated cantaloupes occurred when washed with inoculated cantaloupe in tap water or AS. Cross-contamination did not occur when washing was done in EOW. During peeling and cutting, 1 to 2 log CFU/g of Salmonella and L. monocytogenes were transferred from the rind to the edible flesh of cantaloupe washed with tap water; however, cross-contamination did not occur for EOW treated cantaloupe. Subsequent treatment of mixed flesh from inoculated and non-inoculated cantaloupe demonstrated that EOW treatment reduced the likelihood of cross-contamination compared with tap water and AS. No viable Salmonella or L. monocytogenes was detected from 100 ml sample of EOW processing water.
Significance: Addition of a sanitizing agent to water used for processing of whole and fresh-cut cantaloupe in a retail setting is recommended to present cross-contamination and reduce microbial load on cantaloupe.