COLLEGE STATION A team of Texas AgriLife Research engineers has developed a way to cut by as much as half the amount of irradiation needed to kill 99.999 percent of salmonella, E. coli and other pathogens on fresh produce.
By packing produce in a Mylar bag filled with pure oxygen, Dr. Carmen Gomes, AgriLife Research food safety engineer, and her colleagues found they could significantly reduce the amount of radiation needed to kill those pathogens. Reducing the amount of radiation is not so much a safety measure as it is a way to preserve quality of the produce, she said.
The U.S. Food and Drug Administration recently approved the use of irradiation at dosages of up to 4,000 Gray on leafy greens such as spinach, Gomes said.
A Gray is a measure of ionizing radiation dose and it is equal to the absorption of 1 Joule of ionizing radiation by 1 kilogram of matter.
"That dosage was determined as what was necessary to achieve an 100,000-fold reduction of such pathogens as E. coli O157:H7 and salmonella," said Gomes, who is one of athethree-member Texas AgriLife Food Safety Engineering Team. "However, we know based on previous research conducted by our group that above 1 kilo Gray (1,000 Gray) the quality of leafy vegetables starts to decay and they lose their freshness."
An 100,000-fold reduction corresponds to a 99.999 percent kill rate, according to Dr. Rosana Moreira, another member of the team.
"If you had 100,000 bacteria in your vegetable, it means you would end up with just one bacteria still living," Moreira said.
Though being exposed to a Gray of radiation would be lethal for a human, the radiation leaves no residue on the vegetables, and the vegetables are perfectly safe for human consumption after the process, according to Gomes.
"It is analogous to the heat treatment when you expose milk, juices and cans of vegetables to very high temperatures for a period of time to kill path
|Contact: Robert Burns|
Texas A&M AgriLife Communications