Federal health officials have been warning since early June against eating certain types of tomatoes, and they again refused to rule out the possibility that tomatoes may be responsible for the largest foodborne outbreak in at least a decade.
Tomato growers have complained for weeks that tomatoes are not the cause, and some state health officials suspect tomatoes aren't responsible because they have a limited shelf life and the number of illnesses keeps rising despite the nationwide warning.
The latest government advisory warns against eating jalapeno and serrano peppers, which officials said are often confused with jalapenos. The warning applies to infants, the elderly and those with impaired immune systems.
The new developments are likely to intensify criticism of the government food safety system, after a string of foodborne outbreaks and with the current investigation now in its second month without a clear culprit.
In a hastily scheduled conference call with reporters late yesterday afternoon, officials acknowledged that their investigation had shifted away from tomatoes and toward jalapenos.
"The strategy here is to aggressively pursue the tracebacks of jalapeno peppers," said Dr. David Acheson, associate commissioner for foods at the Food and Drug Administration. That means looking for contaminated jalapenos on farms, at processing plants and in distribution centers, he said.
The shift was prompted by new evidence, accumulated during interviews with those sickened by the Salmonella saintpaul strain since June. Many said they had eaten jalapenos, while a smaller number reported eating tomatoes.
Investigators have yet to find a contaminated tomato or jalapeno.
"We are clear that jalapeno peppers caused some of the illnesses in the outbreak. It is not clear they explain all of the illnesses," said Dr. Robert Tauxe, deputy director of foodborne diseases at the Centers for Disease Control and Prevention.
The acknowledgment that tomatoes are no longer the lone, lead suspect is likely to intensify criticism of the FDA and CDC.
Those federal agencies have been leading the investigation, which is being carried out in conjunction with health departments in Texas, New Mexico and other states.
Tomato growers and sellers have estimated their losses at $100 million so far, while critics in Congress have complained about delays in identifying the source of the outbreak.
There have been repeated calls for an overhaul of the nation's food safety system and the implementation of better methods for tracking produce.
"I've never seen a situation like this," William Marler, a Seattle lawyer who litigates food-borne illness claims, said in a recent interview.
A mistaken focus on tomatoes would be a "black eye" for investigators, he said, while acknowledging that produce investigations are difficult.
Jalapenos are grown mostly in Mexico and, to a lesser extent, in California, Florida and Texas. At the time the outbreak began, Mexico would have been the main supplier but Texas farms would also have been harvesting, said James Ditmore, international marketing specialist at the New Mexico Department of Agriculture.
A 2003 study found that one salmonella strain grew at higher rates on peppers compared with other fresh produce, but the spicy peppers haven't been implicated in many outbreaks. Unlike leafy greens, jalapenos grow well above ground, limiting several normal causes of contamination, food scientists say.
Because jalapenos have a long shelf life - they can be stored in refrigerators for weeks - it's possible that a consumer or restaurant may still have a tainted jalapeno that can be tested for salmonella, food scientists say.
Since people began experiencing fever, diarrhea and abdominal cramps in April, the government has confirmed 1,017 cases of Salmonella saintpaul, including 29 in Maryland.
More than 200 people have been hospitalized.
In issuing a new warning about jalapeno and serrano peppers, officials said they were limiting their caution to the people most vulnerable to infection, though that could change as the investigation evolves.
Officials are still warning consumers to avoid eating raw red plum, red Roma and red round tomatoes unless they came from cleared regions, such as Maryland and more than 40 other states.
The new warning doesn't apply to salsa, even though significant numbers of the infected ate salsa at Mexican restaurants.
Tomatoes and raw jalapeno peppers are key ingredients in salsa.
Though some state health officials say it's unlikely that tomatoes are responsible, federal officials said again that they couldn't rule out tomatoes and implicate jalapenos as the lone cause.
"There is plausible evidence it could be both products," Tauxe said.