Gallery of imported food boutiques at New York store

It all started about three years ago. The little delicacies department of New York's Bloomingdale's department store began to bubble and fizz like an overactive bread dough - with new and rare products appearing overnight, but just as suddenly disappearing.

It was fun but frustrating, because just when you got used to the fact that, yes, Bloomingdale's had this or that esoteric product, it was no longer in stock , or it had been moved somewhere.

I found out why when I sat down for a chat with Raymond Berger, the divisional marketing manager, and Jed Jaffe, the department manager.

All the chopping and changing was not random but part of a long-term plan to make the delicacies department into a genuinely serious source of fine foods, both fresh and packaged, from all over the world.

Truth to tell, it needed re-creating. You used to walk in off 59th Street and find a bakery. Now you find Paris. The bakery has been moved to its own separate quarters a few yards down the block.

The space it occupied, give or take a few square yards, has been converted to two small boutiques, one for Petrossian's and one for Michel Guerard's Comptoir Gourmand.

Petrossian's in Paris, is known as the best supplier of caviar and such things as smoked salmon and other fish delicacies.

This little evocation of the Parisian shop has quickly become just about the best place in New York to buy fresh caviar. It is by no means the least expensive, but my several purchases there have been without exception delicious.

Across the aisle is the glossy maroon ''lacquered box'' housing Comptoir Gourmand. The well-known chef Michel Guerard is most famous for his dietetic cooking as served at his spa in Eugenie-les-Bains, France, but that is only one side of his talents.

The shops in Paris and Lyon, I can report from personal experience, are excellent sources of luxury foods, charcuterie, and so forth, and they also do catering in a small way.

The emphasis in the New York version is more heavily on freshly prepared dishes, although jars and cans with Mr. Guerard's logo are to be found on the shelves as well, most of them of unimpeachable quality.

The fresh foods, some available ''ready to wear'' and some requiring a day or two advance notice, are all prepared from scratch in a new, good-size kitchen, devoted exclusively to the Comptoir Gourmand.

From ''scratch'' means just that - with lovely mild hams, beautifully pink and silky, being cured on the premises.

The choice of dishes cuts across the boundary between rustic and sophisticated ''chef's cooking,'' ranging from layered terrines and decorated pastry constructions to simple boiled dinners.

If Petrossian's prices are high, but justified, Guerard's are simply reasonable, with several main courses available for around $10 a generous portion, and starters and desserts running much less. Prices would be twice as much for equivalent quality in a restaurant.

The Michel Guerard kitchen is headed by Patrick Grangien, who worked with Guerard before coming to New York as part of a team of four cooks.

Products from other French chefs also proliferate at Bloomingdale's, with excellent goods from the Troisgros brothers and occasionally from Alain Chapel, and with a new line of chocolates from the pastry master Gaston Lenotre. It is hoped that the connection with Lenotre will be expanding in the future.

Another food celebrity, more personally involved in the growth of Bloomingdale's as a major factor in the New York food world, is Marcella Hazan, author of the fine ''The Classic Italian Cookbook'' and ''More Classic Italian Cooking.''

She is developing a line of high-quality Italian goods - including fresh pastas (both rolled and extruded), sauces, rare olive oils and vinegars, and fine preserved tomatoes.

Extra-virgin, cold-pressed olive oils will be collected from all the important oil-producing districts of Italy, each of them the best in its class, pressed by a small producer using traditional methods.

Among the new facilities will be a ''cheese cellar'' designed by a master cheeseman from France, which will enable Bloomingdale's to store, ripen, and sell cheese at the peak of ripeness.

So far I may have given the impression that Bloomingdale's is giving short shrift to American cooking and products.

The store might have fallen into that trap a few years ago, when it was fashionable to look down your nose at Indian pudding and Tex-Mex chili, but there is no danger of it now.

Work will soon begin on the American Kitchen, which will highlight the great regional cuisines of the US.

The Southwest is already well represented with a line of ingredients developed in consultation with Jane Butel, author of more than one Tex-Mex cookbook.

The bakery is particularly strong on American classics, including some of the best brownies in the city and excellent Bundt cakes, among them an almond-lingonberry one.

The bakery, incidentally, has moved not o ly physically but in other ways as well. Ovens have been installed in the bread department, for instance, and at least half the products are now baked on the premises, including croissants and some good brick-oven loaves.

The croissants are not on the level of those made by the city's best bakers, but are respectable - and the crusty sourdough bread is considerably more than just that.

Many of the innovations that are making the new Manhattan department so interesting were first tried out in the branch stores. The fact is that the delicacies departments of the branch stores are considered a greater asset than that of the flagship store, because they are often the only place in suburban neighborhoods where their unusual products can be found.

While freshly made pasta can be bought from a good dozen sxores within half a mile of the New York store, the Washington, D.C., branch, for example, is a tremendous boon to noodle fanciers in the capital because of the egg-pasta sheets flown daily from New York and cut into different shapes at the customer's request.

A strong delicacies department in a branch store also generates better business in other areas of sales. While people wander into the New York store and just buy a half pound of cheese and a jar of mustard, suburbanites are more inclined to buy a sweater as well, having gotten into their cars and made the special trip.

Effort is being made to keep quality high and to create something unique, even in Manhattan, an island of unique shops. If the creative director, Pamela Krausmann, and her team keep going in the direction they are now heading, they should have no problem doing that. Except one, perhaps: what to call it all, now that it is manifestly not the old delicacies department anymore.