Horticultural Sciences Department

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Issue No. 607

The Vegetarian Newsletter 

A Horticultural Sciences Department Extension Publication on 
Vegetable and Fruit Crops 

Eat your Veggies and Fruits!!!!!

Publish Date: 
November 2015

Vegetarian Newsletter

November 2015

Postharvest Physical Treatments to Reduce Losses of Organic and Other Locally-Grown Produce While Improving Quality and Extending Shelf Life

Jeff Brecht, UF/IFAS, Horticultural Sciences Department, Gainesville

This research and extension project, funded by the USDA AFRI Food Security program, got underway in 2014 and will continue through 2018.  The project is headed by Dr. Eleni Pliakoni of Kansas State University and includes her KSU colleague Dr. Cary Rivard and University of Florida faculty Dr. Jeff Brecht, Dr. Xin Zhao, and Dr. Jerry Bartz.  Dr. Pliakoni was formerly a postdoctoral associate at UF, working with Dr. Brecht.  They are working on postharvest technology and handling practices for the fresh fruit and vegetable industries that will work for small operators, such as those at farmers’ markets. Smartphone apps to help smaller producers make harvest and handling decisions are in the works, as are hot water treatments to reduce decay and boost antioxidants in fresh produce.  The purpose of the project is to enable small-acreage produce growers to reduce losses by optimizing production and postharvest handling methods, which will stabilize produce availability for local consumers thereby benefiting both the grower and consumers of his products.

The goal of the project is to provide small producers of fruits and vegetables with tools to improve the quality and shelf life of their products and consequently reduce losses. We plan to develop a user-friendly digital tool suite to predict yields, marketable yields, and postharvest food losses of various crops and provide an on-farm tracking system for growers that can be implemented through smartphone technology. Our results will be disseminated directly to growers and agricultural educators via traditional and novel extension methods as well as a grower advisory panel.

 The rationale behind the project is that small-acreage growers need information that is suitable for their operations, including knowledge of how production and postharvest practices affect food losses.

The research is focused on 1) high tunnel vegetable production, 2) postharvest hot water treatment, and 3) modified atmosphere packaging.  The potential benefits of these technologies are described below:

High Tunnel Production

High tunnel production can potentially help growers conserve water, reduce pesticide usage and plant diseases, maintain soil nutrients, and increase crop yield.  The potential with high tunnel production in reducing or preventing plant exposure to rainfall and fog, thereby reducing pathogen loads and subsequent postharvest decays of spinach and tomato, is a particular focus of our planned research.

Hot Water Treatment

Plant tissues are surprisingly tolerant of brief heat exposures that are lethal to many microbes. Application of hot water treatment in the range of 50 to 60 °C for up to a few minutes can thus be an effective, non-chemical approach for controlling postharvest decays in fruits and vegetables. Additionally, plants respond to non-lethal stress such as hot water treatment by increases in antioxidants, which protect against further stress and are also nutritionally beneficial for humans.

Modified Atmosphere Packaging (MAP)

As for heat, plant tissues also tolerate quite extreme modifications of their surrounding oxygen and carbon dioxide levels. These modified atmospheres, when applied postharvest, result in reduced metabolic rates, which result in slower deterioration and loss of quality. The simplest way to achieve beneficial atmospheres is by using packaging (MAP) that restricts gas exchange, allowing the natural respiration of the fruits or vegetables to modify the package atmosphere.

Any small growers who are interested in learning more about the project and even participating in eventual field testing of the technologies can contact Jeff Brecht, jkbrecht@ufl.edu, 352-273-4778.