On the Sunday before Thanksgiving, The Post -- one of the foremost turkeys (unfeathered) of modern journalism -- published a lengthy diatribe attacking the U.S. turkey industry and included North Carolina's turkey producers in the broadside.

I don't mind so much The Post's attacking me, or President Reagan, or the free-enterprise system. I'm accustomed to that. But when the newspaper jumps on an industry of which I am very proud -- that's going too far.

The piece in The Post was written by a fellow named Colman McCarthy, whom I do not know. That may be one of my special blessings. In any event, Mr. McCarthy appeared to be saying that all of us should stop enjoying turkey at Thanksgiving, or at any other time. He implied that Thanksgiving Day is scarcely more than a commercialized holiday created by the turkey industry. So much for Mr. McCarthy's knowledge of history.

His little diatribe bore the headline "Eat a Carrot, Save a Turkey." It's difficult to conjure up a vision of the Pilgrims sitting down to bounteous servings of carrots on the First Thanksgiving. For that matter, it's impossible to imagine what my five grandchildren, not to mention other assorted relatives, would do and say if Mrs. Helms invited them to sit down to a turkeyless Thanksgiving dinner. Saucers and plates would probably fly around the dining room.

Mr. McCarthy even dragged in a gross misrepresentation of the facts in declaring that "turkey meat is very likely to be infected with salmonella bacteria." The truth, of course, is that some bacteria are to be found in almost everything we eat -- including carrots. In any case, the bacteria to which Mr. McCarthy referred are destroyed after the first two minutes of cooking at 160 degrees.

So, while I'm obliged to object to the attack on the turkey industry, I don't anticipate that the increasing numbers of Americans who enjoy eating turkey (or their increasing frequency of doing so) will diminish. They know a good thing when they eat it. So this latest curious advocacy printed in The Post fits in with its endorsement of communist and socialist dictatorships around the world and its relentless efforts to appease the communists in Nicaragua, Cuba and the Soviet Union.

So let's join in lifting our forks in gratitude for the U.S. turkey industry -- and as for The Post, let's just consider the source.

JESSE HELMS U.S. Senator (R-N.C.) Washington