NEW YORK — First there were pushcarts laden with kosher food. Then came small kosher groceries and, later, aisles of kosher products in supermarkets.

Now all-kosher markets, stocked with thousands of kosher food products, are popping up across the country — although none exist yet in the Bay Area.

Furthermore, if a customer cannot get to one of those supermarkets, two online kosher supermarkets offer delivery anywhere in the world.

Kosher food is big business. Integrated Marketing Communications, a company that tracks the kosher food industry, estimates that kosher food accounts for $3.2 billion worth of food sales each year — with more than 40 percent of that spent on food for Passover. Shoppers "know nothing non-kosher has gotten mixed in" with the kosher products, said Shimon Mendlowitz, owner of Wesley Kosher in Wesley Hills, N.Y.

How many people buy their "whole order here?" asked Stuart Kaufman, owner of Katz's Kosher Supermarket in Rockville, Md., one of the nation's oldest all-kosher supermarkets.

Most, he said, pick up a few items at his store and then do their major shopping at a chain supermarket.

Menacham Lubinsky, president of Integrated Marketing, believes all-kosher markets are here to stay. There is "more demand for this type of store," he said. It is "a trend that's just begun."

All-kosher supermarket owners estimate that some 10 percent of their business comes from non-Jews, including vegetarians, black Muslims and Seventh-day Adventists; the latter follow strict dietary laws and do not eat meat.

We want to make a "global village of kosher food," said Alex Schleider, vice president of operations at the online Kosher Supermarket. The virtual supermarket — www.koshersupermarket.com — sells more than 4,000 kosher products.

While Kosher Supermarket sells food one might expect to find at a local store, another online service takes a more selective approach.

Kosher Grocer — www.koshergrocer.com — is "more of a gourmet specialty store," than a traditional supermarket, said Deborah Alexander, who owns the virtual grocery along with partner Craig Diamond.

One customer who hopes to benefit from the virtual supermarkets is Shaindy Harms, a Canadian Jewish woman who is moving to the eastern Arctic region.

Harms, who said she'd go the "ends of the earth to keep kosher," is hooked on online kosher shopping.