The Agriculture Department says it's not biting off more than it can chew, but it is poising a regulatory fork over the American barbecue pit and it's almost certain to hit a bone of contention.

The department is asking for public comment on how to define barbecue, how to cook it, what to look for in a finished rib, whether geographic differences amount to a hill of beans.

In a country that takes its barbecue very seriously, the idea of Uncle Sam mucking around in the hickory chips is something like restarting the War Between the States.

But in case you didn't know, there are federal barbecue regulations. They apply not to the backyard and not to a favorite restaurant, but to the meat processed and sold by commercial distributors. Our good uncle wants to be sure we get real barbecue--in his view, meat cooked over dry heat produced by coals--and he wants it labeled properly. All ribbing aside, that's where it becomes a very meaty issue.

Take North Carolina, for example. Tarheels think their traditional pork barbecue is the only kind of barbecue there is.

Rep. W. G. (Bill) Hefner (D-N.C.), for example, said, "I'd just as soon get the government out of the pits. There's no big secret. You get some wood and a pig and you cook it. That's the key. When they cook it, I eat it. I don't understand why they need a definition."

Oklahomans make a barbecue they claim is best. There are people who swear that Kansas City barbecue pales all else by comparison. Don't even ask a Texan--you'll get a politico-culinary lecture.

House Majority Leader James C. Wright Jr. (D-Tex.) is a case in point. He barbecues at home and he flies in the real McCoy from Texas to serve at his get-togethers for civic leaders. Wright's secret is mesquite wood, a lot of smoke and brisket of Texas steer.

He also has a lecture. He says you prepare barbecue with a Bowie knife, not a Stockman knife (it leaves more fat). You use one Gramm of ketchup (that's for Rep. Phil Gramm of Texas). You use a Latta sauce (for Rep. Delbert L. Latta of Ohio). The recipe goes downhill from there.

USDA has raised the barbecue question under prodding by Maurice Lee, president of Smokarama Inc., a Boley, Okla., company that makes a commercial barbecue cooker that uses hickory wood under pressure to crank out ribs and other succulents.

Lee said one of his California clients was told by state officials that under a truth-in-menu law, barbecue cooked on a Smokarama machine couldn't be called barbecue. Baloney, said Lee, and he mounted a challenge. The state, he said yesterday, backed off.

"But the California standard was pretty much based on the federal standard, so we decided to take on USDA while we were at it . . . . Hardly anyone can define barbecue," he said.

Lee said he felt the USDA definition of barbecue does not take into account modern processing techniques, although he agreed with the intent that meat cooked in the oven and splashed with sauce ought not to be called barbecue.

"USDA privately has agreed the definition needs to be changed," he added, "but the bureaucracy has to go through these public-comment steps . . . ."

Maurice Lee obviously has touched a nerve. Donald L. Houston, administrator of USDA's Food Safety and Inspection Service, which is giving the public until June 1 to have its say on the issue, wasn't taking barbecue calls yesterday.