FDA approves irradiation of iceberg lettuce, spinach

Aug 21, 2008 (CIDRAP News) – The Food and Drug Administration (FDA) today approved the use of irradiation to kill pathogens in fresh spinach and iceberg lettuce, which were linked to Escherichia coli O157:H7 outbreaks that sickened hundreds of people in the fall of 2006.

The intent is to allow irradiation both to eliminate pathogens and to extend shelf life, according to the FDA's new rule, to be published tomorrow in the Federal Register but posted online today. The rule takes effect tomorrow.

Iceberg lettuce and spinach now join meat, poultry, molluscan shellfish, and dried spices on the list of foods that can be irradiated for safety in the United States, said FDA spokesman Sebastian Cianci. The FDA action does not include other varieties of lettuce.

The approval was sought by the Grocery Manufacturers Association (GMA), formerly the National Food Processors Association, Cianci told CIDRAP News. Back in 2000, the group had petitioned for approval of irradiation for a wide range of foods, including raw vegetables and fruits. In December 2007, the GMA asked the FDA for a "partial response" covering just iceberg lettuce and spinach, Cianci said.

"Irradiation is effective in reducing levels of potentially dangerous pathogens such as Salmonella and E coli and will provide an additional tool that may be helpful to protect the public from microbial hazards," Cianci said.

Under the FDA rule, packages of irradiated lettuce and spinach—like other irradiated food products—will have to bear the radura logo and one of two statements: "treated with radiation" or "treated by irradiation."

"This final rule will permit the irradiation of fresh iceberg lettuce and fresh spinach to a maximum absorbed dose of 4.0 kGy [kiloGray], which is effective in reducing microbial pathogens that have been associated with these crops in the past," the FDA said in an e-mailed announcement.

According to an Associated Press (AP) report published today, the FDA concluded that this dose of radiation does not sterilize lettuce or spinach but is enough to "dramatically" reduce levels of E coli, Salmonella, and Listeria without impairing the safety or nutritional value of the foods.

"This isn't going to eliminate the need to wash the product. The FDA continues to recommend that consumers thoroughly wash produce uinder running water before they eat it," said Cianci. "Pre-washed bagged produce can be used without further washing," but not all bagged produce is pre-washed, he added.

"This is not to take the place of other controls; it's an additional pathogen-reduction method," Cianci said.

He said the FDA previously approved irradiation of lettuce, spinach, and some other commodities to kill insects and reduce spoilage, which involved doses lower than those used to kill microbes. He was unsure about to what extent irradiation has been used to kill insects in produce, if at all.

The FDA is still pondering allowing the irradiation of other kinds of produce. Cianci couldn't predict how soon any additional approvals might come.

Fresh bagged spinach grown in California was blamed for an E coli outbreak in the early fall of 2006 that involved 204 cases and three deaths. Later that fall, shredded lettuce from Taco John's restaurants was implicated in two E coli outbreaks, one in Minnesota and Iowa and the other in several northeastern states.

See also:

Prepublication copy of the FDA's Federal Register announcement
http://www.fda.gov/OHRMS/DOCKETS/98fr/FDA-1999-F-2405-nfr.pdf

Jan 12, 2007, CIDRAP News story "FDA finds Taco John's E coli strain on California farms"

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