Header graphic for print
Marler Blog Providing Commentary on Food Poisoning Outbreaks & Litigation

Less irradiation can kill more bugs on leafy greens

ScienceDaily reports in “Killing Salmonella and E. Coli on Fresh Produce With Half the Normal Food-Irradiation Levels” that a team of Texas A&M researchers 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.

Screen shot 2010-12-07 at 3.35.28 AM.pngBy 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. “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. (see E. coli in plant stoma)

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 pathogens,” Gomes said.