FIVE YEARS from now Americans may be eating bacon and sausage preserved by radiation. The new products will contain no sodium nitrites and will be stored without refrigeration.

Irradiated meats may be the food fad of the future.

At least, Dr. Abner Salant hopes so.

Down the hall from D. Salant's office in Natick, Mass., is a room with a 25-foot-deep pool of water in the middle of the floor. At the bottom of the pool, two racks of radioactive cobalt 60 are silently and continuously declaying. The gamma rays color the water with a pale blue light, like muted neon.

The pool, the cobalt and Dr. Salant are part of the U.S. Army Research and Development Command in Natick, the world's leader in preserving food with high doses of radiation.

Dr. Salant, who is director of the Food Engineering Laboratory, and others at the Natick base believe they are close to perfecting a method of preservation for many foods that will replace the conventional processes - freezing, chemical curing, cooking and canning.

"If you believe that logic and reason must persist, then you have to believe this will come to pass. There are so many obvious benefits," said Dr. Salant with the quiet determination of one who has done his homework.

Using gamma rays and high-energy electrons produced by a mammoth Rube Goldbergish device called a linear electronic accelerator, scientists at the Natick labs have been working for 25 years to preserve meats without using chemical compounds or refrigeration.

The process is simple. Conveyer belts run in front of the electron accelerator and into the room with the cobalt 60. Fifteen minutes of exposure to $&(WORD ILLEGIBLE the electron beam, or 70 minutes' exposure to the gamma rays (the cobalt is hoisted out of the water, a natural shield, to irradiate the food), will preserve any food item by killing the micro-organisms inside it.

Scientists for the Army's food-engineering program at Natick pioneered the technique, and now, $50 million in defense funding later, they think they're just about finished. They hope to see irradiated foods approved by the Food and Drug Administration and on the market within four years.

In addition to bacon and sausage, they produce irradiated (and precooked) chicken, steak, codfish, ham, corned beef, pork roasts and turkey.

Much of the food now goes to the NASA space program, packaged in vacuum-sealed metal pouches.

But with FDA approval, that could change.

"Irradiated foods could serve a wide market," said Dr. Salant. "Hospitals could use them, they would be great for soldiers in the field, and they would be terrific convenience food.

Dr. Salant and Dr. Ari Brynjolfsson, chief of the radiated food program at Natick, say that irradiated meats are better nutritionally than meats preserved by heat or chemical curing, contain no toxic chemicals or cancer-causing substances in appreciable amounts. They also consume less energy in production.

And, Dr. Salant hastens to add, "They are not radioactive."

There is, however, the problem of taste. Even a generation of Americans conditioned by fast-food restaurants may have trouble accepting some of the foods. The precooked slices of ham, beef and turkey are as bland as bread pudding and as dull as daytime television. They do not offend, but neither do they please.

The bacon and sausage, though, are surprisingly good. In a recent test, two samples of bacon were offered. One had been prepared with no sodium nitrite, the other with just a fraction of the amount used in bacon commercially. Both had been treated with a fairly low dose of radiation - not enough to sterilize, but enough to extend their refrigerated life 20 days beyond that of conventional bacon. Natick scientists also produce a highly irradiated bacon that they say needs no refrigeration.

The samples were tasty, although the one with nitrite tasted and looked more like commercial bacon than the other. A sample of nitrite-free sausage was delicious.

"I've got a weakness for the sausage," said Dr. Salant, helping himself to a third from the plate. "They're darned good. And safe. I've been eating them for years and the only side effect I've noticed is that I've put on a few pounds."

Sausage and bacon, like other cured meats, are preserved most often with sodium nitrite, which may cause cancer. Meats preserved by irradiation contain few or no nitrites, or nitrates. Proponents cite this as one of the primary virtues of the process.

Sodium nitrite (also called saltpeter) is used in American-produced cured meats to kill botulism micro-organisms and to impart a characteristic flavor and appearance. Its use may be discontinued within the next two years because of its possible carcinogenic qualities.

Scientists at Natick, the FDA and the Department of Agriculture are still debating a Massachusetts Institute of Technology study that links nitrites with cancer growth, but they agree that some nitrosamines, created by the interaction of nitrites and natural secondary amines in meat, do in fact cause cancer.

Irradiated meats contain no nitrosamines, say the scientists at the Natick labs.

They hope the FDA will take this and other factors into account and approve the use of irradiation in chicken by 1983 and, soon after, in other meats, fruits and vegetables.

Approval is awaiting the conclusion of animal-feeding tests being conducted by the Army's surgeon general. In the tests, animals are fed both irradiated and nonirradiated meat to determine whether the irradiation process might produce harmful chemical compounds.

According to Dr. Salant, the tests have so far vindicated the process, suggesting that it does not produce toxic compounds in any amount large enough to be harmful to humans.

Dr. Sanford A. Miller, director of the Bureau of Foods of the FDA, and himself a longtime fan of irradiated foods, agrees with Dr. Salant on most counts.

"I don't think I've ever seen anything that suggests irradiated food isn't perfectly safe. Some chemical compounds are created by the process, but the amounts and toxicity are low. All the studies so far have produced no evidence of hazards," he said.

"But," he added, "most of those studies have not been very good."

Dr. Miller said he could not predict whether the FDA would grant approval to market irradiated chicken until the feeding tests are completed.

He said he had not seen any evidence to prove Dr. Salant's claim that irradiation completely kills botulism micro-organisms.

According to Dr. Salant, the tests on botulism are not finished, but all findings so far indicate that the process kills the bacteria.

If Dr. Miller is properly cautious about accepting all the claims put forth by proponents of irradiated foods he is positively lukewarm about its future in the marketplace.

"I do not think it will sweep the market, but it will find its place. Irradiation is just another tool; it will not be used for every food," he said.

While he expressed doubt about the immediate success of irradiated meats with the public, Dr. Miller said irradiation would be "very useful" in extending the storage life of potatoes, grains and fruits.

But the irradiation of fruits, potatoes and grain does not concern American scientists. Research in that area is mostly handled by scientitsts working in 21 countries other than this one. Using much lower doses of radiation than are needed to preserve meats, they have succeeded in inhibiting sprout production in potatoes in storage, increasing the storage life of wheat and preserving such fruits as strawberries and papayas.

Meanwhile, at Natick, the experiments go on. Problems reamin. There is, for instance, the problem of experience. Not enough is known about many of the chemical compounds found in irradiated meats.

A 1977 report compiled by an independent testing firm in Maryland, the Life Sciences Research Offices, concluded that irradiation of beef did not seem to produce any health hazards, but pointed out also that long-term animal studies on chemical compounds found in the beef (and often in nonirradiated food as well) were rare, and so it is difficult to predict the long-term effects from consumption of irradiated meats.

And in the animal feeding tests still under way, it has been noted that animals that consume irradiated feeds seem to produce larger and more litters than do the other test animals.

"But we don't know if those figures are significant yet; we don't know if they really mean anything," said Dr. Salant.

The biggest problem is the public. Dr. Salant and his co-workers are afraid that many consumers will avoid irradiated food for fear of radiation poisoning, although tests show that the products are not at all radioactive.

"I'll tell you one thing," said Dr. Salant. "That Three Mile Island thing didn't help things one bit."

But there may be a solution. Several years ago, one public-relations-minded soul at the Natick labs noticed that the word "irradiated" encouraged laymen to think of radiation and radioactive substances. So he coined a better, or at least a different, word.

Now, canned irradiated meat is referred to as "radappertized," a combaination of the word "radiation" and the scientific term for canning.

Pass the radappertized chicken, please. CAPTION: Picture 1, Dr. Abner Salant with "irradiated" ham, pork chops, beef, turkey and corned beef. AP; Picture 2, Dr. Abner Salant, by AP