New Jersey joined Pennsylvania yesterday on a list of at least 20 states whose tomatoes have been ruled out as the source of a salmonella outbreak that has been linked to 23 hospitalizations.

The contamination, which led to a consumer warning from the U.S. Food and Drug Administration on Saturday, has been preliminarily traced to raw red plum, red Roma and round red tomatoes.

Though most of the illnesses were reported in New Mexico and Texas, authorities are unsure where the tomatoes originated.

Pennsylvania's and New Jersey's field-grown tomatoes will start being harvested in two to four weeks and are unaffected by the outbreak, agriculture officials said. Greenhouse tomatoes are available now and are safe, they said.

Jersey-grown greenhouse tomatoes began making their way to market in mid-May, state Agriculture Secretary Charles M. Kuperus said yesterday.

That was "well after" the time frame in which the FDA has said the suspect tomatoes were bought and eaten, Kuperus said.

Greenhouse tomatoes are grown in controlled environments and "don't have contamination issues like field-grown tomatoes," said David Specca, director of the Rutgers EcoComplex in Bordentown, part of the state Agricultural Experiment Station System of Rutgers University.

But to those unaware of that, "any tomato will not be a good tomato - and that can kill the market," Specca said.

Groceries throughout the region have removed some tomato varieties from their produce sections. Acme Markets, with 130 stores in Pennsylvania, New Jersey, Delaware and Maryland, has posted signs explaining the recall.

"The health and safety of our customers is Acme's number-one priority," said Taryn Duckett, a spokeswoman at company headquarters in Malvern. "We have voluntarily removed from sale all . . . tomatoes covered under the advisory until further notice."

Several types - including cherry tomatoes, grape tomatoes and tomatoes with the vine attached - remain available, Duckett said.

Growers hope that lack of complete information, and caution on the part of many restaurants, doesn't lead consumers to panic.

"When national chains like McDonald's aren't serving tomatoes, that doesn't help tomato sales," said Bill Troxell, executive secretary of the Pennsylvania Growers Association in Richfield, Pa.

Florida's tomato industry, the largest in the country, is on the verge of "complete collapse," a spokesman for the Florida Tomato Growers Exchange said yesterday.

New Jersey farmers have not suffered financial losses, said Lynne Richmond, a spokeswoman for the state Department of Agriculture. They produced 2,900 acres of tomatoes worth $23.6 million last year, mostly in Cumberland, Gloucester, Burlington, Atlantic and Salem Counties.

The salmonella outbreak "ends up being an argument for buying local," said Peter Furey, executive director of the New Jersey Farm Bureau, whose members include 5,000 full-time farmers.

With fewer miles between producer and consumer, "you have more accountability for the chain of supply," Furey said.

Marilyn Russo, who grows greenhouse tomatoes at Russo's Orchard Lane Farm in Chesterfield, Burlington County, said her business had not been dampened by the salmonella scare.

"We've had people who come in and ask questions all the time, but it hasn't affected sales," she said.

Richard Nieuwenhuis, president of the New Jersey Farm Bureau, said the state's farmers had a good record for food safety.

"We want to assure people that New Jersey-grown tomatoes are safe, fresh, and good for you," he said. "They're produced with a lot of care and food safety in mind."

What consumers need is information, said Troxell, of the Pennsylvania Growers Association.

"If we can get the word out that tomatoes are safe, that might help the greenhouse sales," Troxell said.