Effect of hot water surface pasteurization of whole fruit on shelf life and quality of fresh-cut cantaloupes

Authors: Fan, Xuetong; Annous, Bassam; Beaulieu, John; Sites, Joseph

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/18/2008
Publication Date: 4/2/2008
Citation: Fan, X., Annous, B.A., Beaulieu, J.C., Sites, J.E. 2008. Effect of hot water surface pasteurization of whole fruit on shelf life and quality of fresh-cut cantaloupes. Journal of Food Science. 73(3):M91-M98.

Interpretive Summary: Consumption of melons has been linked to outbreaks of foodborne illness and recalls in the U.S. due to contamination with human pathogens. Food safety intervention technologies are needed for both whole and cut melons. In this study, we investigated microbial population and quality of fresh-cut cantaloupes processed from hot water- and chlorine- treated fruit. Whole cantaloupes were submerged into cold water (10 C) as a control, hot water (76 C) or chlorine solution. Quality and microbial populations of fresh-cut cantaloupes were analyzed during storage at 4 C. Our results indicated that hot water pasteurization reduced native bacteria, yeast and mold population on the whole cantaloupe, which also frequently resulted in lower microbial loads on fresh-cut fruit. Chlorine treatment did not reduce microbial population on the whole or fresh-cut cantaloupes. No negative effect by the hot water treatment on sensory quality or vitamin C content of fresh-cut cantaloupes was observed. Therefore, hot water pasteurization is superior to chlorine, the chemical currently used by the industry. The information should provide the fresh-cut industry a means to enhance safety and quality of cut melons.

Technical Abstract: Melons are associated with recent outbreaks of foodborne illnesses and recalls. Therefore, new approaches are needed for sanitization of whole and cut fruit. In the present study whole cantaloupes were submerged into water in the following three conditions: 10 C water for 20 min (control), 20 ppm chlorine at 10 C for 20 min, and 76 C water for 3 min. Populations of microflora were measured on the rinds of the whole cantaloupes. Quality and microbial populations of fresh-cut cantaloupes prepared from whole fruit were analyzed after 1, 6, 8, 10, 13, 16 and 20 days of storage at 4 C. Results showed that hot water significantly reduced both total plate count (TPC) and yeast and mold counts on rind of whole fruits while chlorine or cold water wash did not result in a significant reduction of microbial population. Fresh-cut fruit prepared from hot water-treated cantaloupes had lower TPC than the other two treatments in the later storage periods (day 13-20) in two of three trials. The hot water treatment was inconsistent in reducing yeast and mold count of fresh-cut fruit. During storage, O2 levels in the clamshell containers decreased rapidly, to levels below 2%, and CO2 levels increased to 15-25%. Soluble solids content, ascorbic acid content, and drip loss were not significantly affected by either hot water or chlorine treatment. Hot water-treated samples had higher aroma and appearance scores at some sampling days in one of the trials. Our results suggested that hot water pasteurization of whole cantaloupes frequently resulted in lower TPCs of fresh-cut fruit during storage, but did not negatively affect quality of fresh-cut melon.