IF YOU HAVE never tasted an Olympia oys-

ter, Tillamook cheddar, a Maine low-bush blueberry or a true key lime pie, Raymond Sokolov has a word for you.

Hurry.

The regional foods are disappearing, homogenized into a bland, easily portable package that can be trucked and trained from one end of the continent to the other, unbruised, unripe and often tasteless.

As a roving food columnist for Natural History magazine, Sokolov spent two years tracking down native American foods and dishes, and his report from the field is fascinating, informative and depressing for anyone not looking forward to a future full of perfect pink tomatoes.

"Americans, typically, have settled for a hybrid fruit of demonstrably inferior quality, but with ideal qualifications for modern agribusiness," he writes, lamenting that the Tahiti lime, larger and thicker skinned, has supplanted Florida's key lime, whose taste he finds "sourer and more complex." Not even in Key West could he find a regular commercial source for the key lime.

In fact, to obtain tastes of many of his fading feasts, Sokolov was forced to contact private sources. He tells how he finally found the American persimmon shoved out of most supermarkets by its larger Oriental competitor:

"I pulled up to a desolate mobile home set behind a half-built house in the early stages of dilapidation. Stepping out of the car, I was attacked by a small mongrel . . . who took a bite of my left ankle. . . . Expecting the report of a shotgun, I waited a minute or two by the car. But no Jukes or Kallikak emerged . . . so I limped across the field toward a scraggly stand of trees. A few feet from them, I slipped on what felt like a spot of mud. It was red orange and had three large black seeds. In the branches overhead, hundreds of similar persimmons dangled. And in the brown grass, strewn in every direction, were squishy- squashy ripe persimmons waiting to be saved."

Sokolov is equally intrepid in his search for Tillamook cheddar, a cheese whose reputation was based on its extra-long aging process, the Olympia oyster, once common on the West Coast but now a rarity because it matures slowly and never gets very large at that, and the small, intensely flavorful Maine blueberry, another victim of the preference for size over taste. His difficulty is our delight as we accompany him to Michigan's Upper Peninsula where he collects a recipe for Roast Bear Paws and Cornish pasties (made by a Finn) to Boyne City, Michigan, where he takes part in the National Mushroom Hunting Championship, to Broussard, Louisiana's second annual Louisiana Boudin Festival and a sating of Cajun sausage, and to Owensboro, Kentucky, where he finds an almost authentic burgoo.

One of the major reasons burgoo has been replaced by Burger King is the ease with which food can be shipped from one part of the country to another, leading to the development of specialized agribusinesses and a homogenized national taste. Lettuce grown in California makes the overland trek to New York state, which could perfectly well grow the greens itself. Rodale Press recently released information gathered by its Cornucopia Project which shows that New York, the second largest agricultural producer in the Northeast, nevertheless imports 75 percent of its own food at a transportation cost of $1 billion a year.

It is factors like these and how they have affected man's development which are explored in Food in Civilization. Less concerned with food per se than how it has influenced the way we live, Carson Ritchie writes that "the quest for food has tended to bring down untold misfortune on mankind."

He writes of how man's success as a hunter led to a decrease in game and the necessity to turn to farming, and how over-farming eventually led to the ruin of great tracts of land, which led to migration, which led to wars between opposing tribes, and then countries, for space in which to grow food.

Like many surveys which try to cover too much in too little space, Food in Civilization hops past a variety of interesting topics without ever saying enough about any of them. In one nine-page chapter, we go from the enclosure movement to the diet of factory workers, to an interesting but somewhat irrelevant discussion of Benjamin Franklin's drinking habits, to the introduction of the turnip, a long-keeping vegetable whose use as fodder meant cattle could be kept alive during the winter instead of being slaughtered in the fall, to the McCormick reaper and John Deere's steel plow.

(For a much fuller account of how such inventions shaped our lives, see the excellent Eating in America, by Waverly Root and Richard de Rochemont, a well-written and well-researched history which has recently been re-issued in paperback by Ecco Press for $9.95.)

But while Sokolov mourns the passing of diversity and Ritchie plays a gloomy game of food and consequences, with Andr,e Simon we retreat into the pure joy of food.

Simon's A Concise Encyclopedia of Gastronomy, first published in 1952, has been out of print for some years, and its reappearance will bring pleasure to anyone seriously interested in food. It often covers the same ground as the Larousse Gastronomique, but choosing between them would be like trying to choose between two favorite aunts.

The Encyclopedia, written with Simon's lighter touch and charmingly eccentric concerns, complements the more classically oriented Larousse. Under Lobster, for instance, Simon consults one "Mr. Joseph Sinel, late of the Jersey Marine Biological Laboratory, (who) at the request of the S.P.C.A. made some experiments to ascertain which was the more humane way of boiling crabs and lobsters." Putting them in cold water and bringing the water to a boil wins out. "With the lobster placed in cold water and the boiler put on the fire, there was no evidence of discomfort, nor any attempt made by the lobster to emerge from the water, until the temperature reached 70 degrees when the lobster gradually collapsed and fell on its side."

One of the pleasures of the Encyclopedia lies in Simon's use of his extensive collection of old cookbooks, providing, for instance, 30 pages of recipes on how to prepare a chicken. (The back of the book contains a list of all his sources.)

The Concise Encyclopedia of Gastronomy is worth owning not only for its information on food and its recipes, but for such entertaining trivia as the following:

"The largest Cheddar cheese ever made was a monster Cheddar made from the milk of 750 cows by the people of East and West Pennard, in Somersetshire, in the Cheddar district, as a bridal offering to Queen Victoria, in 1840. Its weight was 11 cwt., its circumference 9 ft. 4 in. and its depth 20 in. The Queen graciously accepted the present but the farmers asked that it might be exhibited. Their request was granted but the Queen declined to have it back after the exhibition. The farmers then quarrelled among themselves, their cheese got into Chancery, and it never was heard of any more."

And there it may still be, aged to a turn that would make even Sokolov's Tillamook taste bland.