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United States Department of Agriculture

Agricultural Research Service

Title: Maintaining the Analytical and Microbial Quality of Fresh-Cut Apple Slices Using Hot Water Pretreatment and Low Ph Processing Treatment

item Saftner, Robert
item Abbott, Judith
item Bhagwat, Arvind

Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: March 24, 2005
Publication Date: June 20, 2005
Citation: Saftner, R.A., Abbott, J.A., Bhagwat, A.A. 2005. Maintaining the analytical and microbial quality of fresh-cut apple slices using hot water pretreatment and low ph processing treatment [abstract]. Hortscience. 40:1005.

Technical Abstract: A calcium ascorbate dip treatment is commercially used to prevent browning on fresh-cut apple slices but has little to no antimicrobial activity against spoilage or foodborne pathogens. Intact apples were surface sanitized by dipping for 1 to 3 min in sodium chlorite solution pH 6.0 at 20 ºC or water at 60 ºC, processed into fresh-cut slices, and the slices dipped in calcium ascorbate or a solution of isoascorbic/ascorbic acid, calcium, and N-acetyl-L-cysteine at pH 2.0. The commercial and experimental dip treatments similarly maintained cut surface color, Kramer firmness and aromatic volatile concentrations during three weeks storage at 5 ºC in air. Freshly prepared experimental dip treatment reduced the native bacterial population of the apple slices prepared from sanitized apples better than the calcium ascorbate treatment. With repeated use, the experimental dip solution became adulterated with apple tissue and juice and rapidly lost its antibacterial activity. Concomitantly the pH of the dip solution increased to 2.6 or higher. The lost antibacterial activity could be restored in highly contaminated experimental wash solutions by back titrating to pH 2. The experimental dip treatment also reduced the overall yeast and mold population, but specifically enhanced survival of Pennicillium expansum on the apple slices prepared from sodium chlorite-sanitized apples. A hot water pretreatment of intact apples at 60 ºC for 2 to 3 min prior to fresh-cut processing essentially eliminated P. expansum contamination on fresh-cut slices. The results indicate that the experimental wash treatment is a promising alternative to calcium ascorbate treatment for analytical and microbial quality retention of fresh-cut apple slices during storage, especially when the apple slices are processed from hot water-treated apples.

Last Modified: 4/21/2015