(FORTUNE Small Business) – Memorial Day 1981: eight months after the very first Whole Foods Market debuted, a massive Texas flood destroyed it, filling the store with eight feet of water and muck and overturning refrigerators. "I figured we were out of business," says chief executive John Mackey, who spent the night wallowing out in front of his organic food store with a six-pack of beer. But the next day a steady stream of customers showed up with mops and buckets to help clean up--part of the reason the store reopened a mere 30 days later. "Customers working day and night for no reimbursement--that was a clear message that Whole Foods would be enormously successful," says Mark Skiles, one of Mackey's co-founders.

That kind of fierce customer loyalty has built Whole Foods from that one store to 143 today and $2.7 billion in sales and $85 million in profits last year. In that time Mackey both drove and rode the surging interest in organic products. In 1990 organics was a $1 billion business; it's $11 billion today and expected to grow to $20 billion by 2005, according to the Organic Trade Association. Although Whole Foods' revenue is a tiny fraction of the $1 trillion food market, it's expanding. Same-store sales are up an average of 10% over the past year and a half, compared with negative numbers at many traditional grocery chains.

Mackey, known from the beginning as a go-getter with grand visions and a "cowboy way of doing things," created a health-food superstore that combines the best of the natural-foods world--knowledgeable service and organic goods--and the selection and comforts of a supermarket: meat counters, big, gleaming aisles, and conventional brands such as Cheerios and Heinz ketchup. That deft combination lets Whole Foods appeal to both the natural-foods hippie and the mom who regularly shops at Safeway.

Sometimes Mackey's cowboy attitude gets him in trouble. The organic community, whose mantra is "Small is beautiful," has criticized Whole Foods for everything from acting like a big corporation to hiring non-union workers to weak food-processing standards. Oddly enough, those charges only position the company toward the mainstream. "We're in the business of selling whole foods, not holy foods," retorts Mackey. Even so, he still seeks credibility within the organic world. He's rolling out a campaign to sell more products made by local farmers, known as the Authentic Food Artisan line, highlighting them with a red seal.

Mackey, who expanded Whole Foods mostly by acquiring like-minded regional chains, is running out of companies to acquire and will now have to grow his sales organically. To do so, he plans to open new, bigger stores in the nation's top 25 metro markets. Over the past five years the average size of a Whole Foods Market has increased by 33%, and larger stores equal more selection, which might mean a customer won't have to visit Safeway at all. Mackey also launched a store brand last year to appeal to customers who don't want to pay more for organic products. His goal? Some 70 new stores by the end of next year, and 300 stores and $10 billion in revenue by 2010. "This--healthy foods, us--isn't just a fad," he says. "My work is not yet sated."