NEW YORK — Barely 24 hours after Mayor Michael Bloomberg proposed an all-out ban on plastic foam food containers in the city and already New Yorkers are asking: So what do we use instead?

Bloomberg's announcement Thursday left consumers and food vendors big and small wondering what a city free of plastic foam might look like.

Polystyrene foam containers have long been used by street vendors and takeout restaurants as a cheap way to keep in the heat — and sauces — of meals sold to on-the-go customers.

Paul Gopaul, 29, owner of the popular Midtown food truck Faith's Halal Food, said a ban on foam containers would force him to switch to more expensive aluminum ones.

Gopaul estimated he uses 500 plastic foam food containers a week, which he buys in packs of 175 containers that sell for $15 at a Queens supplier. The aluminum containers of equal size run about $5 more per pack, he said.

"Right now it's a lot of regulations, but if that's what it takes to keep us out here, then we got to do it," he said.

The mayor's proposal is not an original idea. A number of cities on the West Coast, including San Francisco, have enacted such legislation. Some states have partial or industry-specific bans of the material's use. In Maine, for example, bait can't be sold in polystyrene foam plastic.

In Seattle, the City Council enacted a plastic foam containers ban and the response there has been largely muted.

Although commonly referred to as Styrofoam, that brand of polystyrene foam isn't used in food packaging, according to its manufacturer, Dow Chemical Co.

Plastic foam cups that keep drinks hot would also be on the chopping block if Bloomberg's citywide ban becomes law. That means Dunkin' Donuts, which has about 480 store locations throughout the five boroughs, would be in a bind. The company said it uses paper cups at its stores in four U.S. cities that have polystyrene bans.

"A polystyrene ban will not eliminate waste or increase recycling; It will simply replace one type of trash with another," Dunkin' Donuts said in a statement.

Avid Dunkin' Donuts coffee drinker Charles Smith, 45, said he's sympathetic to the environmental concerns of polystyrene foam, but Bloomberg's latest initiative misses the point.

"I think there are a lot of things in New York that are bad for the environment, like cars and buses," said Smith, who works in the security field. "True New Yorkers just want their coffee."

The proposed plastic foam ban is the latest in a series of public health initiatives launched by the mayor in his 11-year tenure. Others include banning trans fats from restaurant meals, forcing chain eateries to post calorie counts on menus and limiting the size of some sugary drinks.