T11-05 A Novel Antimicrobial Sanitizer for Enhancing Microbial Safety of Whole Melons Designated for Fresh-cut Preparation

Wednesday, August 6, 2014: 9:30 AM
Room 203-204 (Indiana Convention Center)
Dike Ukuku, U.S. Department of Agriculture-ERRC-ARS, Wyndmoor, PA
Lee Chau, U.S. Department of Agriculture-ARS-ERRC, Wyndmoor, PA
Introduction: Wash-water chlorinated up to 200 ppm is routinely applied to reduce microbial contamination in produce processing lines. However, the use of chlorine is of concern due to the potential formation of harmful by-products. Therefore safer alternative sanitizers for fruits and vegetables are needed.

Purpose:  Lovit, a sanitizer that consists of short chain organic acids generally regarded as safe (GRAS) in combination with nisin + ethylenediaminetetraacetic acid (EDTA) was developed and used to investigate the survival and inactivation of Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes bacteria on produce surfaces (cantaloupe, watermelon and honeydew).

Methods: E. coli O157:H7, Salmonella spp. and Listeria monocytogenes were inoculated on cantaloupe, watermelon and honeydew rind surfaces at 4.2 ± 0.21, 4.8 ± 0.14 and 3.9 ± 0.17 log CFU/cm2, respectively.  Inoculated produce were washed with water, hydrogen peroxide (3 %), chlorine (200 ppm) and Lovit solutions for 5 min. Bacterial populations that survived treatments and transferred to fresh-cut pieces were estimated using selective agar media.

Results: The Lovit treatment led to viability loss of 3.5 log for three pathogens tested on cantaloupe and a loss of 2.8 log on watermelon and honeydew rind surfaces, compared to 2.2 log reduction by hydrogen peroxide and chlorine. In fresh-cut cantaloupe pieces prepared from Lovit treated melons, the populations of E. coli O157:H7, Salmonella spp. and L. monocytogenes bacteria were below detection (< 1 CFU/g) and honeydew and watermelon fresh-cut pieces were negative for these pathogens by enrichment. An average of 0.74 ± 0.12 log CFU/g of all three pathogens were recovered from fresh-cut pieces prepared from chlorine and peroxide treated whole melons.

Significance: Treating whole melon surfaces with Lovit solution before fresh-cut preparation will improve the microbial safety and quality of the prepared fresh-cut pieces, and will drastically reduce the incidence of foodborne illness and costly recalls of contaminated produce.