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.”
Both Beattie and Olson say American consumers are more willing to buy irradiated food than they may have been in the past. And the concern that zapping greens might leave them limp or cause them to taste differently is no longer an issue.
“There’s been a lot of research done on that, and basically, products that have treated with irradiation are as good or better after 14 days (typical travel time) than those that haven’t,” Olson said.
“We now know that in order to kill E. coli on this type of product, we can turn down the dosage level – the power of the beam – effectively, and lettuce and spinach remain just as crisp and wholesome as if you grew it yourself,” Beattie said.
He added, “The American consumer has shown willingness to purchase irradiated products such as strawberries and meats. Once consumers understand the food safety implications, their unfounded worries about the safety of the cold pasteurization process are eliminated, even though there are a lot of naysayers and anti-irradiation people giving inaccurate information.”
“The experience with ground beef is that consumers have not reacted negatively to the label,” Olson said. “The only negative reaction is to price. It costs more.”
The Iowa State professors are quick to point out that irradiation will not solve every instance of illness-causing bacteria on produce. Good agricultural practices, such as control of irrigation water and washing water, restriction of animals in produce fields, and personal hygiene of workers all affect the safety of fruits and vegetables. Further, safe food handling practices at home and in food service establishments also are important to ensure the safety of produce.
“In 2006, there were an estimated 50 billion servings of green, leafy salads served in this country, and there were approximately 1,200 people made ill,” Beattie said. “The odds of getting a food-borne illness from produce are already extremely low based upon the number of servings that we see. But what we have to recognize is that irradiation is one more tool we can use to ensure the safety of our products. This is especially important for at-risk populations – immune-compromised folks, pregnant women, children under the age of eight, and elderly. These people are at high risk for food-borne illness and it may be useful to feed them greens that have been irradiated, for that last margin of safety.”
Olson noted, “The real importance of this rule is that produce companies wouldn’t even look at the technology unless the government approved it. The new FDA rule makes them more inclined to take a fresh look at it.”Dennis Olson, Animal Science, (515) 294-3697, firstname.lastname@example.org
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