July 2023 - 14

COVER STORY
Left, peaches in a 30-gallon tank are hydrocooled in a highly oxygenated water and ozone solution.
Right, A manual analog penetrometer measures peach firmness. Photos courtesy UGA Extension.
KEEPING IT FRESH
Postharvest fruit research at
UGA focuses on reducing waste
BY CHRIS KOGER
MANAGING EDITOR
W
hile the dilemma of how to feed a rapidly
increasing population has focused primarily
on how to increase yields through growing
practices or improving the plant itself, a growing field of
research focuses on reducing food waste.
At the University of Georgia's (UGA) College of
Agricultural and Environmental Sciences, Angelos
Deltsidis is working on research projects designed to
ensure that Georgia fruits, vegetables and nuts get eaten.
Deltsidis, UGA professors and grad students at the Vidalia
Onion Research Laboratory in Tifton, Georgia, have been
testing the use of ozone to suppress disease/fungal growth
on peaches, blackberries, onions and other fresh produce
during short-term controlled atmosphere storage. Orestis
Giannopoulos, a UGA postharvest physiology graduate
student who works in the lab with Deltsidis, planned, set
up and executed the ozone experiments.
Tests have also focused on ozonated water to sanitize
fresh peaches prior to packing. Because ozone breaks
down quickly, it is approved for use on organic crops,
Deltsidis said.
Peach tests have focused on gaseous and aqueous
ozone. For aqueous ozone, peaches are hydrocooled in
water in which ozone has been dissolved. Hydrocooling
quickly after harvest eliminates shelf-life sapping heat.
The lab has hydrocooled the peaches for 30 minutes,
15 minutes and 7.5 minutes.
14 | JULY 2023
Although the tests with aqueous ozone have been
limited to batches of about 100 peaches, if the research
warrants full-scale implementation, commercial
hydrocoolers would be used and ozone would be used to
replace water chlorination.
The facility was built in 1994 for research on
controlled atmosphere (CA) storage of the famous
onions, but the research now includes Georgia
vegetables and fruit. Using the facility's 15 CA storage
rooms, researchers can test different concentrations of
oxygen, carbon dioxide and ozone.
" (Ozone) suppresses disease growth and in general
sanitizes the air or water that they (fresh fruits and
vegetables) are washed in, " Deltsidis said.
Ozone, however, is highly reactive and can damage
plant tissue and not just pathogens, creating a mission
for the UGA postharvest physiologists.
" I work hand in hand with industry, and I do targeted
projects, trials and experiments to solve issues that
need a short and quick answer, " he said, " but getting a
short and quick answer is very often not possible due to
the complexity of live organisms. "
Deltsidis has been working on ozone research for
about three years, but cautions against telling packers
and shippers that ozone is an across-the-board
postharvest, CA storage solution to extend shelf life for
all fruits and vegetables.
" There are a lot of moving pieces in reducing food
waste, " Deltsidis said. " A lot of technologies are
complementary to cold storage. Some are easy, but

July 2023

Table of Contents for the Digital Edition of July 2023