Extending Produce Shelf Life
Consumers who are more conscious of eating healthy want fresh, delicious tasting produce. Fresh fruits and vegetables are largely produced far from the cities and populated areas. They are very perishable and decompose in a few days and cannot withstand the long-distance transportation. To counteract these problems, researchers are continually looking for methods to extend the shelf life of fresh produce. Toktam Taghavi, Ph.D., who joined VSU’s Agricultural Research Station in 2017 as an assistant professor in horticulture, leads the Postharvest Research Program, a multidisciplinary research program to extend the shelf life of fresh fruits and vegetables.
One of Taghavi’s current research concentrations is improving postharvest quality of strawberries, and she’s focused on how essential oils can be used to achieve that end. Previously, she has studied many different sustainable methods during pre-harvest and postharvest to extend the shelf life of fresh produce. She has used irrigation and illuminating techniques, as well as natural products such as plant extracts and minerals to extend shelf life. Produce can be dipped in, exposed to or sprayed by a natural product. “Extending the shelf life of produce by even one or two days can make a tremendous difference,” she said. Taghavi explores what impact the methods she studies will have on the fruit’s firmness, sweetness, acidity, color, flavor, gas exchange and disease development.
Postharvest research is important because once fruits and vegetables are picked they can no longer receive water from the mother plant. At the same time, they lose water and begin to soften, which makes them vulnerable to disease. “Quality rarely improves after postharvest,” she said. “The only thing growers can do is to maintain quality. Therefore, we train growers to do their best to produce a good-quality product and then do their best to maintain the quality after harvest.” Growers are looking to halt the decomposition process, which goes against the nature of the produce, which are inherently inclined to soften and decompose to disperse their seed for reproduction. The first step is to cool down the temperature of the produce quickly using precooling methods by water or forced air. Precooling addresses about 80 percent of the postharvest issues, while other postharvest measures address the remaining 20 percent. “It’s challenging for small growers to do the precooling process because they don’t have the facilities to do so,” Taghavi said. “The infrastructure is costly, which makes it hard for a small grower, yet whatever the growers do at the farm is going to make a big impact on the quality of produce that is stored.”
Once Taghavi has a solution, she collaborates with Horticulture Extension Specialist Reza Rafie, Ph.D., and other Extension personnel to promote it to growers. “The work I do is for growers, so the connection with Extension helps to transfer this knowledge to the community. That connection is vital, especially with small growers,” she said. “Large growers have a lot of resources, so small growers are the ones that need the most help, and I’m happy to help them.”
Inspired by her father who introduced her to agriculture, Taghavi trained to be a horticulturist. While pursuing her postgraduate studies she focused on plant nutrition, because it is one of the fundamentals of plant growth and development. Later on, she became involved in postharvest physiology research. Within that domain she can investigate the physiological processes and molecular genetics of the produce receiving the sustainable production and postharvest practices. She has spent much of her research career assisting small farmers, first in her native Iran, then in Florida, Canada and now Virginia. Her research is important, she said, because of the importance of fresh fruits and vegetables to the human diet. “We cannot underestimate the importance of fresh fruits and vegetables for good health, yet still people don’t consume enough,” she said. “The challenge in my work is finding sustainable ways to extend the shelf life of produce at the highest quality after harvest.”