The U.S. Department of Agriculture should stop handing out hot dogs and other processed meats to the nation's children through the lunch program because these products have been shown to increase the risk of cancer in adulthood, said a petition for rule-making and enforcement scheduled to be filed Thursday with the federal government by the Cancer Project.

The petition includes declarations of support from several prominent nutrition and cancer experts, including Dr. Neal Barnard, president of the Cancer Project.

"Just as tobacco causes lung cancer, processed meats are linked to colon cancer," Barnard said in a statement. "With 58 research studies examining the links between processed meats and colorectal cancer, serving these products to children is no longer defensible. The federal government should be encouraging schools to serve healthful foods."

The petition is based on findings reported last year by the American Institute for Cancer Research and the World Cancer Research Fund that concluded that the risk of colorectal cancer increases by 21 percent for every 50 grams of processed meat consumed daily -- approximately the size of a typical hot dog.

The National Pork Board said studies showing no connection between processed meats and cancer weren't included in the report cited by The Cancer Project. The group also said

Dr. Ronald Kleinman, a pediatric gastroenterologist at Massachusetts General Hospital and Harvard, has challenged the alleged link between processed meats and cancer.

The Cancer Project is an affiliate part of Physicians Committee for Responsible Medicine, which has been criticized for having links with militant animal rights activists.