Alternative stores are making a dent in the traditional supermarket business, and a recent call from an irate citizen offers one reason why:

"Have you been in the [local supermarket] lately? Have you seen what they've done to it! My God! It takes all day to shop. you have to go through the pharmacy in order to get from the vegetables to the butter.

"I suppose they think you'll buy all kinds of things you don't need if you have to wheel your basket past them."

Many other consumers are expressing similar sentiments. One, complaining that it just takes too much time to shop now, concludes: "I've always wanted to try some of those small markets around. I bet they've more expensive. I wonder if the quality is any better?"

At the other extreme are shoppers who don't care about the size of the store as long as they can save money. They, too, have begun forsaking the traditional supermarkets. Look for them in a discount outlet, like the Warehouse Food Market in Baltimore.

"It's a pain in the neck, but it's cheap. You can't get up and down the aisles sometimes, it's so crowded," one man said. "The variety is not what it is elsewhere and there's no consistency. Sometimes they have one brand, sometimes another. But everything is pennies cheaper. Some things are a dollar cheaper."

Rising food costs which show little sign of abating, the lack of personalized service in large supermarkets, the quality of the perishable merchandise - for all of these reasons and others, more and more people are doing some or all of their shopping elsewhere.

Retailers are aware of the trend away from supermarkets, and within the last year, several stores have opened which offer limited assortments of food at much cheaper prices. Last September, Discount Food Outlet made its debut in Rockville. It sells dented - but safe - cans, packages without labels, items boxed in bulk. The merchandise varies from week to week, but business, according to the owner, Frank Zoche, is booming.

"We've increased our retail business 200 percent since last fall," Zoche claims. "And our wholesale business has tripled."

In August, a 5,000-square-foot warehouse store, Stanley Discount Food, opened in Frederick. It carries about 450 items, as opposed to the 10,000 or so found in a regular supermarket. Owner Ralph Thomas says the store marks up merchandise 15 percent over cost, which he says is about 8 percent less than the markup at supermarkets. There are further discounts for caselot purchases.

Thomas says he doesn't need as much markup as a regular supermarket because his overhead is lower. Like Baltimore's Warehouse Food Store, Stanley Discount Food is located in a low-rent district. The merchandise remains in its boxes, and the setting is "plain pipe rack." There are no frozen foods - and therefore no costly equipment - and only a few items which require refrigeration.

However, the store provides bags and boxes in which to cart the groceries; and it will cash checks and take food stamps.

Thomas says "We're already making a profit which I've put back into the inventory. We started with $16,000 worth of stock and now, probably, we have $35,000. We're in an area where people really need a break on their groceries."

So is the Warehouse-Store in Baltimore, which opened in June. Like many alternative markets, the Warehouse store is owned by a regular supermarket operator: Foodarama, a small chain in the Baltimore area. While it has the same plain atmosphere as other discount stores, it offers a much larger selection, including fresh produce, a complete line of choice-grade meats, dairy products and frozen foods. It sells only 1,000 items. You cannot always find the brand of tomato sauce you want. Sometimes you can't buy sugar. The meat is sold in three or four-pound packages. The quality of some of the produce is not as high as that sold in the area's better supermarkets.

But the savings are there - 15 to 20 percent below the ordinary supermarket in Baltimore and even more than that compared to Washington prices: Crisco for $1.78 compared to $2.49 here; Nestle's Chocolate Morsels for $1.78 instead of $2.09; Kleenex for 66 cents instead of 75; bananas for 19 cents a pound versus 23 cents.

The Warehouse store has had a significant effect on business of some competing nearby supermarkets. According to three different sources, the supermarket across the road has lost $90,000 a week in business; and others have been offering specials in an attempt to compete with the Warehouse prices.

A variation on the warehouse-discount concept opened recently in Fairfax, Va. Ultra-Mart offers between 3,000 and 4,000 non-perishable and frozen food items for 5 to 15 prcent below regular supermarkets. Shopping is done by telephone from a catalogue. The customer drives up to the warehouse and picks up the already-bagged groceries.

Again, prices are lower because the overhead is considerably less.

Belonging to a cooperative is another way people save money. However, it involves time as a volunteer to buy and deliver the groceries, which are purchased from a wholesaler at some saving.

In May, members of several of these informal cooperatives formed a new store at Montgomery Village in Gaithersburg. Called Wheat and Meat Retreat, it is a combination of two cooperatives - one formed to save money, and one organized to purchase natural and organic foods for less. People can earn a 15 percent discount at the store by working four hours a week for four weeks.

According to one of the founders, Pat Herlan, the store's prices are "considerably less than other health food stores" because some of the workers are volunteers.

Herlan says the store, located in a small complex called the Village Market, "is coming along. We are just beginning to be able to pay minimum wages to a few people." The shop joins a number of other successful natural food stores in the Washington area. Even though most of what the store sells costs more than a regular supermarket, there are enough people willing to pay the price in order to buy additive-free foods. Along with a variety of nostrums of questionable health benefit, many natural food stores offer whole foods unavailable in most supermarkets.

Wheat & Meat shares the complex with other shops appealing to those for whom price is less important than quality and service. Next door is Glenn's Cove, a brand new fish market. Five years ago, Washingtonians could choose from only a bandful of markets that specialized in fish. Now there are a number.

The owner of Glenn's Cove is a 21-year-old former employe of a large chain who decided to follow in the footsteps of a successful uncle with a fish market. "People want more personalized service. They like the way we treat them. I know almost all of them by name."

When people shop there they are not looking for the cheapest fish; they are looking for the best quality, information and service.

At the other end of the market area is a greengrocer who, with his partner, also operates the open-air market on New Hampshire Avenue in Silver Spring. It opened about 10 years ago, in the forefront ofthe alternative shopping movement.

Nick Boccabella says his market is successful because "the merchandise is fresher, has more eye appeal and the prices are a little bit better than the supermarket."

Those are some of the same reasons that the produce trucks, which set up on the main arteries leading into Washington each summer, are so successful. There are a lot of people who prefer to eat strawberries from Maryland's Eastern Shore instead of from California.

It is impossible to determine the effect these forays into alternative shopping are having on the ordinary supermarket. According to a spokesman for the Food Marketing Institute, an association of food retailers and wholesalers, there are no statistics available. "Industry profits are down this year," he said, "but the usual explanation is inflation."

"But," he said, "the general line on this is that the supermarket will always be there and will always have a dominant position."