''Most restaurants (and hostesses) that feature pasta provide guests with a large spoon as well as the knife and fork. The fork is used to spear a few strands of spaghetti, the tips are placed against the spoon, which is held on its side, in the left hand, and the fork is twirled, wrapping the spaghetti around itself as it turns. If no spoon is provided, the tips of the fork may be rested against the curve of the plate.'' ''The New Emily Post's Etiquette,'' Elizabeth L. Post, 1975 By CRAIG CLAIBORNE

WITH America in the throes of what has been called the ''pastarization of the nation,'' when enthusiasm for fusilli and fettuccine, ziti and spaghetti is at an all-time high, it may be time to pause to examine what is right and what is wrong with various techniques for cooking and eating pasta.

For example, is it proper, as Emily Post says, to twirl spaghetti against a spoon? Or, as she also says, with the tips of the fork resting against the curve of the plate? Should bread be served with pasta, another starch? Is it correct to sprinkle cheese on pasta with seafood sauce? When cheese is in order, what is the best cheese? Should strands of long pasta be broken before being tossed into the pot?

The owners of three of the best-known Italian restaurants in Manhattan recently convened to feast on pasta and discuss just how and with what it should be eaten. The diners were Adi Giovanetti, proprietor of Il Nido, and his wife, Rosanna; Sirio Maccioni, owner of Le Cirque, and his wife, Egi, and Luigi Nanni, proprietor and chef of both Nanni's and Il Valetto. The elflike Mr. Nanni cooked, preparing two pastas with sauces, one of which contained Fontina cheese and wild field mushrooms (cultivated mushrooms, he said, could be substituted), and a salsa alla militare or military sauce made with tomatoes, fresh basil and dried hot pepper.