Protective Surface Coating to Reduce Bacterial Load of Fresh and Fresh-cut Produce: Cantaloupe as a Model

<p>NON-TECHNICAL SUMMARY: <br/>Fresh and fresh-cut produce have been a major cause of foodborne illnesses. Among all produce, cantaloupe is particularly susceptible to both Gram-positive and negative pathogens. The goal of this project is to create a technology platform for designing antimicrobial formulations which need negligible capital investment and minimal material cost to protect fresh and fresh-cut produce. As the general approach, we will select natural, food-grade antimicrobial compounds and examine the strategies that can extend or improve antimicrobial efficacy in fresh and fresh-cut produce. Cantaloupe will be used as the model due to its high susceptibility to pathogen contaminations over the whole process from production to consumption. In this project, we will: (1) examine the interactions of antimicrobial compounds and evaluate their antimicrobial efficacies
in model systems, (2) design antimicrobial coating for cantaloupe whole uncut fruit and fresh-cut, and (3) organize extension workshop and conduct field trials with cantaloupe growers. The technology derived from this project will substantially enhance the food safety of cantaloupe products and other fresh and fresh-cut produce.
<p>APPROACH: <br/>Research: The research activities will be conducted in two phases. In phase-1, model systems will be used to examine the effects of antimicrobial compounds against pathogens. In phase-2, with the basic knowledge gained from the model systems, antimicrobial formulations will be developed for cantaloupe whole fruit and fresh-cut. Phase-1: examine the effects of antimicrobial compounds in model systems In the first year, we will focus on studying the interactions among natural and food-grade antimicrobial compounds and their efficacies against food pathogens. The work will include the preparation of model systems, determination of antimicrobial efficacies, and evaluate the performance of specific systems. With this work, we expect to better understand the performances of various antimicrobial compounds against pathogens, and to identify antimicrobial
preparations with substantially improved efficacies in the model systems. Phase-2: design antimicrobial coating for cantaloupe whole uncut fruit and fresh-cut There are two major sources for the contamination of whole uncut cantaloupe: (1) contamination from soil-originated bacteria in the form of biofilm, and (2) contamination caused by the use of pathogen-containing wash water. Specific formulations will be designed against both contamination sources. The work will include: (1) pre-harvest and post-harvest inoculations, (2) preparation of and treatment with antimicrobial formulations, and (3) determination of bacterial load. We expect that the specifically designed formulations will be able to improve the efficacies of antimicrobial compounds by reducing bacterial diffusion and growth during transportation and processing of cantaloupes. For cantaloupe fresh-cut, we will examine
specific formulations for their capability to realize sufficient antimicrobial activities in the juicy environment at the surface of fresh-cut. The work will include: (1) preparation of antimicrobial systems, (2) evaluation of system stability, (3) applying the antimicrobial preparations to fresh-cut surface, and (4) evaluate the bacterial growth at surface. We expect that specifically designed formulations may maintain antimicrobial effect for over 5 days. Extension: Most extension activities will be conducted in the 2nd and 3rd year of this project. The goal of these activities is to provide technical support to local and national cantaloupe growers and collect feedbacks from them for further improvement. We will work with South Indiana melon farmers to monitor their cantaloupe cleaning procedures and evaluate the effect and economy of antimicrobial formulations. The Southwest Purdue
Agricultural Center (SWPAC) will be involved in these activities. Combined, watermelons and cantaloupes are grown on nearly 10,000 acres in Indiana with nearly $50 million annual value, and the majority of the acreage is located at southwest Indiana. A primary mission of SWPAC, which is based in Vincennes, IN, is to provide extension support for growers in the southern region of the state. Headquarter of SWPAC provides meeting space, farm shop, greenhouses, laboratories, as well as other facilities for conducting lab and horticultural experiments. It also provides summer workforce to pick crops and collect data, onsite plant pathologist and agronomist to support both fundamental and applied research, and leads the communication with local growers and processors of agricultural products. At least one extension workshop will be organized with SWPAC in the summer of 2016 for the local
and national cantaloupe farmers and processors. The workshop topics will include: (1) marketing trends of cantaloupe and other melons, (2) physiology and biochemistry of cantaloupe fruit and its fresh-cut, (3) product quality and nutrition, (4) quality control at harvesting, cleaning, packaging, transportation and retailing, and (5) microbiology and sanitation of cantaloupe whole fruit and fresh-cut. Promotion of workshop will be conducted through professional organizations as well as local trade organizations. Field tests and formulation trials will be conducted with melon growers in the southwest Indiana area, which will include: (1) monitoring the microbial load of wash water in cantaloupe cleaning facilities; (2) conducting onsite trials of antimicrobial formulations; and (3) evaluating economic feasibility of using antimicrobial formulations.