211: Effect of Rosemary Oil-Incorporated L-Arginine Cross-Linked Carboxymethylcellulose Edible Coating on Microbial Safety and Storage Stability of Cantaloupe Under Cold Storage

Introduction

Cantaloupe has become a significant source of bacterial outbreaks in the US. The objective of this study is to assess the effect of rosemary oil-incorporated L-arginine cross-linked carboxymethylcellulose edible coating (RO-LA-CMC) in reducing Escherichia coli and Listeria monocytogenes load and preserving the physicochemical properties of whole cantaloupe under cold storage.

Methods

The coating solution was prepared by dissolving 0.5 g CMC and 0.25 g L-arginine in 100 mL deionized water at 70°C, stirring until clump-free. The mixture was heated to 90–100°C for 1 hour and cooled to room temperature. Tween 80 (1.6% v/v) and 4.4% v/v rosemary oil were added, followed by ultrasonication at 20 kHz, 80% amplitude for 5 minutes. Fresh whole cantaloupes (~500 g each) were divided into three groups: control 1 (uninoculated-untreated), control 2 (inoculated-untreated), and TCS (inoculated-treated with coating). The coating was applied by dipping, and samples were stored at 4°C for 12 days. Microbial counts (Escherichia coli, Listeria innocua (surrogate), yeast, and mold) were measured at 3-day intervals. Physicochemical properties, including pH, titratable acidity, total soluble solids (TSS), moisture content, and weight loss, were monitored over 12 days. Data were analyzed statistically (p < 0.05).

Results

TCS showed significantly lower (p < 0.05) Escherichia coli and Listeria innocua loads than both controls throughout the 12-day storage. The maximum log reduction for E. coli was on day 12 (1.72 ± 0.08 log CFU/cm²), and for L. innocua, it was on day 3 (1.16 ± 0.45 log CFU/cm²). Yeast and mold counts were significantly lower (p < 0.05) in TCS across the storage period, with notable reductions on day 6 (1.28 ± 0.03 log CFU/cm²), and day 12 (1.39 ± 0.57 log CFU/cm²) compared to controls. No significant differences were noted between TCS and controls for pH, titratable acidity, or total soluble solids (TSS). However, TCS had significantly lower (p < 0.05) weight loss (0.17 ± 0.12 g) and higher moisture content (91.21 ± 0.37%) on day 6 compared to controls.

Significance

The study highlights the potential of RO-LA-CMC as an effective method to address cantaloupe-related foodborne outbreaks. It has promising applications for enhancing the safety and shelf-life of produce.

Authors: Chien-I Hsu, Tharindu Trishan Dapana Durage, Kaushalya Wickramasinghe, Mariel Benigno, Mario Melendez, Sathivel Subramaniam