WASHINGTON — Imagine picking up a T-shirt with the label: Product of the United States, China, Indonesia and/or Honduras. Confused?

Shoppers could see labels like that in the supermarket meat case, starting this fall. A law requiring meat to be labeled with the country of origin takes effect Oct. 1, but rules that resulted from a compromise among industry interests might leave consumers scratching their heads.

The law, altered by the new farm bill, allows special labeling for ground meat and for products of hogs and cattle that were born in Mexico or Canada but fattened and slaughtered in the United States. The U.S. Agriculture Department last week issued rules for interpreting the modified law.

A lot of pork will likely carry the label: "Product of the United States and Canada."

Allowing that label means packers won't have to keep track of whether the hogs they are slaughtering were born in Canada or the United States. Millions of young Canadian pigs are imported for fattening in the Midwest each year, and packers don't want to have to process them separately from U.S.-born swine. The common label means they won't have to.

Labels for ground beef could be even longer. Industry officials say any one package of ground beef often contains meat from a variety of different countries. But under the new rules, packers won't be required to keep track of what beef goes into a particular package.

Instead, they'll be allowed to list all of the countries from which they have purchased beef during a particular period. So in the supermarket, ground beef could be labeled like this: "Product of the United States, Canada, Mexico, Australia, New Zealand and/or Uruguay."

It's the same idea used in listing ingredients on bags of potato chips. They typically list all the various vegetable oils, such as corn, cottonseed and sunflower, that the processor uses in making chips, not the specific oil that was used in making the chips in any given bag, said Mark Dopp, who follows the issue for the American Meat Institute, a packers' trade group.

The rules should certainly make it easier for processors, but is this really helping shoppers? Chris Waldrop of the Consumer Federation of America thinks so.

"It will provide them with information that they haven't had up until now," he said. "It will at least give them a group of countries that the meat could have come from. If they are concerned about any one of those countries, they can shop elsewhere."

Whether this has any real impact on consumer behavior remains to be seen.