WASHINGTON -- While advocates of reform for rules governing food expiration may have a strong case, the likelihood the federal government will take action is low, said Miriam J. Guggenheim, a partner at Covington and Burling in Washington.

“From a Food and Drug Administration perspective, nothing will happen,” Ms. Guggenheim said.

An attorney whose practice involves labeling and advertising issues for food companies, Ms. Guggenheim was responding to a recent paper published jointly by the Natural Resources Defense Council and Harvard Law School, asserting that more than 90% of Americans “may be prematurely tossing food because they misinterpret food labels as indicators of food safety.”

Steps advocated by Harvard and the N.R.D.C. included making “sell by” dates invisible; establishing clear, unambiguous language predictably located on packaging; and pursuing the deployment of “smart labels” to help consumers learn more about product safety.

“We need a standardized, common sense date labeling system that actually provides useful information to consumers, rather than the unreliable, inconsistent and piecemeal system we have today,” one of the authors of the report said.

The study makes its case colorfully, noting that enough food is wasted each day in the United States to fill the Rose Bowl. According to the groups, about 25% of the nation’s freshwater is used for the production of food that is wasted and food waste costs the average American family of four between $1,365 and $2,275 per year.

Ms. Guggenheim’s skepticism about chances the F.D.A. will act reflect the fact that the issues described in the paper in no way address the agency’s principal food-related focus today – reducing the incidence of foodborne illness.

“They hardly have enough to do what they need right now,” she said. “It’s the opposite of a safety issue. It’s a waste issue.”

Passage of a standalone law by Congress also is unlikely, Ms. Guggenheim said.

“You would need a federal law that preempts existing state laws,” she said. “That would be a heavy lift.”

History supports Ms. Guggenheim’s doubts about Congress. The Harvard/N.R.D.C. paper cited multiple failures in the past when legislators attempted to pass laws aimed at harmonizing food expiration labeling.

Congress in the mid-1970s introduced at least 10 bills, none of which was a success. Similarly, in 1999 the National Uniform Food Safety Labeling Act of 1999 was proposed but stalled within the House Energy and Commerce Committee.

While self-regulatory steps taken by industry to address the problem may be possible, Ms. Guggenheim said Congressional action could not be ruled out completely.

“I wouldn’t see Congress passing a federal law on its own,” she said. “But reforms could be included in other legislation on a trajectory to pass.”