Every morning, surrounded by spoons, bowls and flagons of milk, executives of the Kellogg Co. gather for one of the most solemn rituals in the church of American industry.

Like the millions of children they have enticed to the breakfast table with television, decoder rings and intergalactic space kits, they eat cereal.

Actually, they are testing the 22 different ready-to-eat cereals produced by Kellogg plants here and in 18 countries around the world.

There are Sugar Corn Pops, Apple Jacks and an array of other concoctions, but through it all the mainstay is the corn flake.

Battle Creek is the home of the corn flake, an accident of the 19th century health-food craze. The flake and most of its half-breed cereal brothers were invented here. Now, as at the turn of the century, Battle Creek remains the cereal capital of the world.

Corn from Battle Creek made breakfast what it is today in the big picture, the cereal makers use just a small portion of the corn grown by American farmers. But with its twist on nutrition claims and the fact that Kellogg alone spends about $140 million annually just to advertise its cereals, the handiwork of Battle Creek represents the ultimate commercialization of corn for the consumer.

Kellogg, the kingpin of the heavily competitive industry, is headquartered here. The Post division of General Foods, started by C.W. Post with his Postum cereal drink and Post Toasties (his version of flaked corn), is based here. The Ralston Co. makes cereals here. They all use gobs of corn.

Every day Kellogg executives lift their test spoons, their plant here will use the equivalent of 16,500 bushels of corn, the yearly crop of a 200-acre farm, probably in Illinois, where Kellogg buys most of its raw material. It will become flakes, loopes, pops, crumbs and other marketables.

The air of Battle Creek smells sweetly of Kellogg's Froot Loops, which contain corn. Another byproduct of the health binge, radio station WELL, provides the music. The W. K. Kellogg Foundation, among America's five wealthiest, is based here, next door to Kellogg Community College.

From the time W. K. Kellogg went to market in 1906 with his newfangled corn flake, it has been ever upward and onward for the captains of the breakfast tables. Nobody put it better than anuthor Gerald Carson, who called Kellogg a "worker along the American alimentary canal."

The story is a compelling mix of industrial process, hucksterism and religious-like devotion that has glorified the grain and changed the eating habits of the world. It also has made a lot of people infinitely rich, although they tend not to be corn farmers.

But why all of this in Battle Creek, a city of some 40,000 in southern Michigan, somewhat removed from the grain belt to the south and west of here?

The credit goes largely to Dr. John Harvey Kellogg and Will Keith Kellogg, his younger brother, who grew up hre in a Seventh Day Adventist family that adhered strictly to church dicta of no meat, no tobacco, no alcohol.

Long before it was headquartered in Takoma Park, Md., the church's operations were run from Battle Creek. The church operated a health sanitarium, open to all who sought relief from the dyspepsia induced by pork, grease, bourbon and other heavies of the 19th-century American diet.

The sanitarium became world-famous, and Dr. John Harvey Kellogg, a surgeon of many talents and health zealot without peer, became director. He innovated with nuts and grains, trying to put variety on the sanitarium menu. His innovations included peanut butter (he's considered its inventor) and a range of ready-to-eat cereals to which wre attributed great nutritive powers.

Those claims, while not entirely without foundation, may be judged by company practices today. Corn flakes, for example, the direct product of the grit in a kernel of field corn, are bombarded with vitamins and minerals before they are sent to market.

For years, as John Harvey doctored, invented, spoke and wrote, his handyman was his brother, Will, who, with no more than a grade-school education, found his place as a janitor and bookkeeper at the sanitarium.

The brothers fought constantly, and in later years were suing each other regularly over business matters. But in one of their better moments, entirely by accident, they discovered the flaking process that would lead to corn flakes.

In 1894, while tinkering with boiled wheat dough during one of their searches for another cereal food to grace the patients' tables, they were called from their lab. Returning hours later, they decided to run the dough through metal rollers, even though it was no longer fresh.

Instead of the sheet of wheat they expected, out came flakes. The time lapse had allowed moisture to move uniformly through each wheat berry in the dough, which led to individual flaking.

Patients liked the flakes, and Dr. John Harvey set up a processing company to sell sanitarium foods to patients who wanted a supply at home.Brother Will became his partner in 1899, a year after they cranked their first batch of corn through the steel rollers.

The Kelloggs used the whole kernel, and the corn flake wasn't as popular as the wheat flake. But when Will discovered a better flake by using only the grit, or the heart of the corn, with some malt flavoring, an empire was about to be born.

Will and the doctor parted ways after Will wanted to go on his own in the cereal business, devoting himself entirely to corn flakes. By 1906, when Will at age 45 got around to opening his factory, everyone else in Battle Creek had horned in on the act.

There were already 42 cereal companies registered to do business, and 108 brands of corn flakes were being producted there by 1911.

One of the firms, the Postum Cereal Co., was going great guns. It was set up by C. W. Post, a frail businessman who went to Battle Creek, almost broke, for the sanitarium cure in 1891.

Post stayed, invented Postum and Grape Nuts, and was doing more than $1 million a year in business by 1903. Post's version of corn flakes came out in 1906, the same year Will opened his plant.

Post, of course, went on to become a multimillionaire, as did Will Kellogg, but Post really was no match for the sales genius of his rival. Kellogg plunged heavily into advertising, and one of his gambits is still viewed with awe by the industry.

When Kellogg's production was still limping along in 1906, he advertised in The Ladies Home Journal, offering free corn flakes to consumers who could persuade dealers to carry the product. A flood of orders came in, and Will Kellogg never looked back.

Within five years he was spending $1 million annually on advertising, and making money hand over fist.

Then, as now, the Battle Creek appeal had as much to do with convenience as with a philosophy of diet. The promoters capitalized on the appeal of nourishing grains. And with ready-to-eat cereals, they made breakfast easy, and liberated the housewife from some early-morning drudgery.

The latest generation of lock tenders along the alimentary canal is reminded constantly of old Will Kellogg's insistence on a flake of consistently golden quality, as near to the original as taste buds and automation will allow.

For a man like W. E. LaMothe to become chairman and president of a company as big as Kellogg ($2.1 billion in sales in 1980), he has to know his corn flakes. When he puts his test spoon into a dish of flakes from, say, Venezuela, all eyes turn to LaMothe.

"This is toasted too much," LaMothe may say. Or, probing flakes flown in this week from Japan, he may comment, "This is just too spotty."

This is quality control to the nth degree. People take notes, and plant managers are notified: your flakes are slipping; get on the stick.

"Our worldwide image is important," said Arnold G. Langbo, president of Kellogg's U.S. food products division. "Once a week, corn flakes from all over the world are flown here for checking against the real one.

"The formula is identical the world over. Yet we've had to call our world people in from time to time and teach them what a corn flake is and what its standards are."

Added Gary Costley, a PhD in nutrition and a senior vice president: "We make it by the carload but people consume it by the spoonful. We live or die by the repeat purchases. That's why the image and the quality are so important."

In the huge Kellogg main factory here (56 acres of floor space), the only major difference in the founder's process is the size and the automation. Kellogg merchandising stresses the convenience and the nutrition of the processed grains, with corn as king.

The corn grits are cooked under pressure with sugar, salt and malt, then subjected to roller pressure of 40 tons to create the flakes.

Never-ending belts carry the flakes through tall rotary ovens, nutrients are sprayed on and the flakes pour through tubes to the floor below, where they go into boxes that are filled, weighed and sealed at a rate of 76 packages per minute, 700,000 packages a day.

Kellogg executives count on the quality of the flake to keep drawing customers back, but there is no let-up on the competitive hard-sell. Kellogg and the industry as a whole have been blistered with criticism for their heavy use of sugar on some cereals and their targeting of children for advertising.

Kellogg responded by establishing a "nutrition policy" in the 1970s, and professionals like Celeste Clark carry the company message of good-health-through-cereal across the country, not, she says, because Kellogg is "defensive" but because it is "responsive."

"Mr. Kellogg absolutely wouldn't tolerate criticism of his corn flakes," said Gary Costley, "so this place went crazy in the 1970s when all the attacks came. There was a sense of institutional arrogance. . . . But Ralph Nader, Robert Choate and others made fantastic contributions to nutrition with their criticisms.

"Now, a lot of thought goes into what we're doing. We've earned a modicum of respect. We're not monsters."

But they never miss a trick in Battle Creek. Visitors to the plant, as many as 200,000 a year, encounter a huge statute of Tony the Tiger outside the door. Kids never fail to ask about Tony, the Kellogg symbol since 1952. t

Nancy Sackrider, a tour guide, hands every visitor a box of corn flakes on the way out. And she answers every kid's inevitable question. "We say Tony's in California, doing TV commercials," she said.

Someplace out there, old Will Kellogg must be beaming. KERNELS

The Kellogg Co. is No. 1 among cereal producers, with about 40 percent of the U.S. market. Its top item is still the regular corn flake; its second-biggest seller is the sugar-frosted corn flake.

Kellogg's Corn Flakes and Post Toasties are made in plants opposite each other along Porter Street in Battle Creek, but nearness does not mean neighborliness. Kellogg and Post people have little to do with each other. The rivalry goes back to the beginning. In 1913, Kellogg propaganda summed up Post Toasties this way: "A spritely two-year-old, sired by Post and damned by the consumer."

When C.W. Post brought out his corn flakes in 1906, he called his product Elijah's Manna, after the biblical prophet. Churchmen railed at him for the sacrilege. In 1908, the clamor ceased when he changed the name to Post Toasties. CAPTION: Picture 1, An early advertisement for Kellogg's Corn Flakes, part of an ongoing campaign that began in earnest in 1906, when Will Kellogg plunged heavily into selling his product through the media. Within five years the annual advertising budget was $1 million, and Kellogg was making money hand over fist. Today, millions of children are enticed to the breakfast table with television, decoder rings and intergalactic space kits.; Picture 2, A 1912 photograph of the annual employes' picnic at the kellogg plant in Battle Creek, Mich, still cereal capital of the world.; Picture 3, WILL KEITH KELLOGG . . . he discovered a better corn flake