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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOPING PROCESSING INTERVENTION TECHNOLOGIES

Location: Food Safety and Intervention Technologies

Title: Effect of organic acid treatments on microbial safety and overall acceptability of fresh-cut melon cubes

Authors
item Ukuku, Dike
item Mukhopadhyay, Sudarsan
item Olanya, Modesto

Submitted to: International Journal of Food, Agriculture, and the Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 20, 2013
Publication Date: December 5, 2013
Citation: Ukuku, D.O., Mukhopadhyay, S., Olanya, O.M. 2013. Effect of organic acid treatments on microbial safety and overall acceptability of fresh-cut melon cubes. International Journal of Food, Agriculture, and the Environment. 11(3&4):340-345.

Interpretive Summary: Presence of human bacterial pathogens and spoilage bacteria on fresh-cut cantaloupes is a food safety hazard. There is much interest in developing effective minimal processing methodologies for fruits and vegetables that would enhance the microbial safety and not change overall acceptability. In this study, several organic acids (EDTA, nisin, sorbic acid and sodium lactate) generally regarded as safe (GRAS) were individually tested or used in combination to evaluate their ability to kill Salmonella and reduce the populations of spoilage bacteria on fresh-cut cantaloupes cubes. Bacterial populations including Salmonella spp. in fresh-cut pieces dipped in organic acid solutions listed above declined depending on the type of acid used. A solution containing all the listed organic acids killed the most bacteria in fresh-cut pieces; however, only fresh-cut cantaloupes pieces treated with sodium lactate scored a “very good” in overall acceptability ratings.

Technical Abstract: There is much interest in developing effective minimal processing methodologies for fruits and vegetables that would enhance the microbial safety and not change overall acceptability. In this study, several organic acids (EDTA, nisin, sorbic acid and sodium lactate) generally regarded as safe (GRAS) were individually tested or used in combination to test inactivation of Salmonella on fresh-cut cantaloupes cubes. Fresh-cut cantaloupe cubes contaminated with Salmonella spp. at 3.3 log CFU/g were dipped in solutions containing individual compounds listed above or a combination for 3 min. Inoculated and treated fresh-cut cantaloupes pieces were stored at 5 deg C for 14 days or left at room temperature (21 deg C) for 24 h. Bacterial populations and overall acceptability of the fresh-cut pieces based on physical appearances were investigated. Average populations of native microflora of fresh-cut cantaloupes prepared from control and water washed cantaloupes were 2.9 log CFU/g and 2.3 log CFU/g, respectively. During fresh-cut preparation, Salmonella populations transferred from control and water washed cantaloupe rind surfaces to the fresh-cut pieces averaged 1.4 log CFU/g and the populations on fresh-cut pieces prepared from chlorine-washed cantaloupes averaged 0.8 log CFU/g. Overall acceptability rating for these fresh-cut pieces was 10 despite the presence of Salmonella bacteria. Treatment with sodium lactate resulted in a 0.2 log reduction of Salmonella and the fresh-cut cubes had the highest overall acceptability rating (8) amongst all treated fresh-cut pieces. Bacterial populations including Salmonella spp. in fresh-cut pieces dipped in organic acid solutions declined depending on the type of acid used. Higher bacterial inactivation occurred in fresh-cut pieces dipped in nisin-lactate-sorbate combination, but treatment resulted in a score of only 6 in overall acceptability.

Last Modified: 7/24/2014