PITTSFORD, N.Y. - Five minutes into a tour of his flagship grocery store, Danny Wegman has already wolfed down a berry tart, cherry walnut sourdough bread topped with havarti cheese, white frosted cake, and cauliflower curry.

Wegman, whose namesake supermarket company has won a pile of customer service and best-workplace honors, is known to have a weakness for the product samples his stores feature. His appetite for competition is similarly voracious.

The New York chain, with 78 stores in five states, will open its first market next Sunday in Massachusetts, a food emporium so massive it will instantly be the largest grocery in New England.

The arrival of a Wegmans in Northborough is likely to raise the stakes for every grocery seller in the region. While the company has fewer stores than other supermarket chains, its combination of natural and organic products (like Whole Foods ), bulk merchandise (like BJ’s Wholesale Club), and low prices (like Market Basket) give it an outsized presence in the industry.

Wegman, 64, wiry and ginger-haired, visits the Pittsford store, in a suburb of Rochester, at least once a week. On this day, shoppers run up to him as if they have spotted a long-lost friend and he returns the affection. Between greetings, he poses for a photographer, dressed in a loose-fitting blue silk shirt emblazoned with a brick print. Not exactly corporate-conservative.

And then he disappears - just as a spokeswoman earlier predicted. If there’s a customer in need of attention, or a food sample to be had, Wegman will be off in that direction, she warned.

Everyone in the place seems, to a skeptical visitor from Boston, unnaturally happy to be here. Hunting for someone who isn’t completely taken by the Wegmans experience, a reporter spots a woman with an empty cart. Maybe she can’t find her favorite cereal. Turns out Nancy Reale has just started shopping.

“When you’re in Wegmans, it feels very personal. You get to know everyone and it feels like stores within stores,’’ says Reale, who moved from Massachusetts to Rochester in 1976. “In Boston, supermarkets were very impersonal, just a group of shelves with people stocking them. We’re never going to move away from our Wegmans. They are always imagineering.’’

Imagi-what?