Iowa State University experts can discuss new FDA produce irradiation rule

AMES, Iowa – The Food and Drug Administration's new (Aug. 22) regulation that will allow irradiation pasteurization to be used on fresh spinach and iceberg lettuce to kill illness-causing bacteria is a step that two Iowa State University professors have long advocated.

Dennis Olson is a professor of animal science and directs Iowa State's Linear Accelerator Facility, one of only two commercial-sized irradiation facilities for food research and demonstration on a U.S. university campus. He has researched food irradiation for more than a decade, and is an expert in food safety, particularly in the area of meat processing. (The FDA has allowed irradiation of red meat to control pathogens since 1997; in poultry since 1990).

Had the FDA rule been in place sooner, Olson is convinced that irradiation could have prevented some of the illnesses and three deaths that occurred during spinach and lettuce outbreaks in 2006.

"If we treat all of the lettuce and spinach, then there's going to be a very rare instance of exposure to illness-causing microorganisms," Olson said. "What's sad is that the FDA, after a nearly nine-year review, selected only two products involved with the massive illnesses in 2006." The FDA is still considering what other types of produce might be safely irradiated – for example, other leafy vegetables, tomatoes and peppers.

What's significant about the new FDA rule is that it is the first time the federal government has allowed produce to be irradiated at levels sufficient to kill E. coli, salmonella and listeria – microorganisms that make people sick. The FDA has approved the use of irradiation to eliminate insects from wheat, potatoes, flour, spices, tea, fruits and vegetables since 1985, but it couldn't be used to treat vegetative pathogens until now.

Cost and consumer acceptance are two obstacles that still stand in the way of large amounts of leafy greens being treated with irradiation.

"I suspect it will take awhile for the supply chain to get into place because of the limited number of irradiation facilities in place in the U.S.," said Sam Beattie, Extension food safety specialist and an assistant professor of food science and human nutrition at Iowa State. "These facilities are relatively expensive to build, so you have to make sure you have adequate product flow and a market for that product."

"It would have to be new construction, that's for sure," Olson added. "We wouldn't expect any immediate adoption, and in fact industry won't move forward unless they are sure there won't be a backlash from consumer activists. The other issue is that there is a lot more product now being labeled organic, and you cannot irradiate products labeled organic."