SEATTLE — Amazon continues to expand grocery delivery from its Whole Foods Market stores, a service now available in 48 cities across the United States.

The retailer this week introduced grocery delivery in Milwaukee; Omaha; Detroit; Madison, Wis.; St. Louis; Ann Arbor, Mich.; Tulsa, Okla.; and three Florida cities — Tampa, Orlando and Jacksonville — and added more stores in the New York and Seattle areas.

Shoppers who have paid the $119 membership fee to be an Amazon Prime Now member can browse and order fresh produce, organic meat, seafood and other items from nearby Whole Foods stores. Customers can also choose free pickup in as little as an hour on orders of $35 or more.

The company began rolling out two-hour delivery of groceries from Whole Foods stores last winter.

Earlier this year, Bloomberg News reported that Amazon was searching for bigger Whole Foods locations that would serve as both grocery stores and urban distribution centers that could help the retailer shorten delivery times. At the same time, Amazon reportedly was working on a project to convert parking areas at existing Whole Foods stores into stalls for delivery contractors to load up their orders.