Federal health officials yesterday warned consumers most at risk of severe infections to avoid eating fresh jalapeno and serrano peppers, in addition to certain types of raw tomatoes, as the investigation into a nationwide salmonella food poisoning outbreak widens.

Now spanning three months, the salmonella outbreak has become the largest incidence of food-borne illness in more than a decade. The most vulnerable are the elderly, people with weak immune systems and infants.

Since April, there have been 1,017 confirmed cases — all with the same rare genetic fingerprint in the salmonella bacteria — in 41 states, the District of Columbia and Canada, according to the Centers for Disease Control and Prevention. At least 203 people have been hospitalized.

One death, of a Texas man in his 80s, has been linked to the outbreak. Another Texas man, in his 60s, who died of cancer, was infected with the outbreak strain.

The outbreak far surpasses what had been considered the largest of the past decade — 715 salmonella cases linked to peanut butter in 2006, according to the CDC.

TEXAS WORST HIT

Last week, officials started testing peppers for Salmonella saintpaul, but did not issue a warning yesterday. Health officials targeted the jalapeno warning at a smaller segment of the population than in the one previously issued for tomatoes because they have not linked specific jalapeno varieties to the outbreak.

"We thought of this as our way of protecting those at greatest risk as more information develops about jalapenos," said Robert Tauxe, a top official with the CDC. The CDC is leading the probe along with the Food and Drug Administration.

The tomato recommendation — to avoid red plum, roma and vineless red round tomatoes grown outside certain areas — remains in effect for all consumers.

Texas has reported 384 salmonella-related illnesses, followed by Illinois with 100 and New Mexico, where the outbreak was first detected, with 98.

The new recommendation is not likely to have as broad an economic impact as the tomato warning because jalapenos are not consumed as widely, but it is likely to add to the woes of growers and importers whose shipments have been held in recent days for testing by the FDA.

Investigators added jalapenos, cilantro and serrano peppers to the list of suspects last week based on a new round of interviews with people who got sick in June. Officials began considering other types of produce after people continued to fall ill despite the June 7 warning to avoid certain tomatoes.

The jalapeno warning was based on the results of recent investigations of three large clusters of illnesses involving restaurants, the CDC said. A cluster is when at least two people get sick after eating in the same location within a brief period of time.

ECONOMIC IMPACT

The impact of the jalapeno warning rippled through the food industry yesterday.

"We are going to put a hold on our raw jalapeno inventory," said Mark Palmer, spokesman for Sysco, the largest food distributor in North America.

The company will stop distributing as well as receiving the peppers.

Jalapenos cannot be the sole culprit — because many of the ill insist they didn't eat hot peppers or foods like salsa that contain them, CDC food safety chief Dr. Robert Tauxe said. As for serrano peppers, that was included in the warning because the two peppers are difficult for consumers to tell apart.

MORE THAN ONE CULPRIT

In some clusters of illnesses, jalapenos "simply were not on the menu," Tauxe said. "We are quite sure that neither tomatoes nor jalapenos explain the entire outbreak at this point. ... We're presuming that both of them have caused illness."

That has FDA inspectors looking hard for farms that may have grown tomatoes earlier in the spring and then switched to pepper harvesting, or for distribution centers that handled both types of produce.

Also still being investigated is fresh cilantro, because a significant number of people who got sick most recently say they ate all three — raw tomatoes, jalapenos and cilantro.

"I understand the frustration" that after weeks of warnings, the outbreak isn't solved, Tauxe said. "But we really are working as hard and as fast as we can to sort out this complicated situation and protect the health of the American people."

Tauxe said the concern about peppers does not include salsa in jars that consumers purchase in stores.

MYSTERY UNSOLVED

It's possible that officials may not be able to trace the source of the outbreak, acknowledged David Acheson, the U.S. Food and Drug Administration's food safety chief.

"We've got a lot of horses working this. ... It's just been a spectacularly complicated and prolonged outbreak," Acheson said.

He said that the FDA is not warning consumers against eating jalapeno and serrano peppers, but that a warning could come as the investigation continues.

Officials continue to caution consumers to limit tomato consumption to specific types of tomatoes and sources that have been deemed safe. The safe tomatoes include cherry tomatoes; grape tomatoes; tomatoes sold with the vine still attached; tomatoes grown at home; and red plum, red roma and round red tomatoes from states listed at the FDA's site (www.fda.gov/oc/opacom/hottopics/tomatoes.html).

McClatchy-Tribune News Service, the Washington Post and Associated Press contributed to this report.