Was slicing tomatoes from our menus worth it?

More than 1,200 people in 42 states now have been sickened by a rare strain of salmonella bacteria carried on tomatoes … or maybe hot peppers. Or maybe both.

Federal investigators on Thursday said they still aren't sure but declared all tomatoes now on the market safe to eat.

Americans have continued to get sick – at a rate of about 20 people per day – even after the Food and Drug Administration's June 7 warning to not eat three popular types of tomatoes drove restaurants, distributors and grocery stores to dump tomatoes by the crate at an estimated cost of $100 million to $250 million.

Produce industry leaders, furious over the muddled investigation, are demanding the government be more certain the next time it banishes tons of vegetables to the garbage. Congressional hearings have been set for the end of the month.

"They have this zero-tolerance policy, and it really doesn't make much sense," said Jim Prevor, a produce industry consultant and editor of Produce Business magazine. "They ignore all of these cases, but on the odd chance they get knowledge of (an outbreak), they become like Ahab pursuing the whale."

Epidemiologists say the kind of certainty the industry seeks is beyond the reach of their science. Investigators often must rely on the ability of outbreak victims to recall details of meals eaten weeks in the past. The Centers for Disease Control and Prevention employs some of the world's best food-safety investigators, but their conclusions are often somewhat uncertain and occasionally flat wrong.

"We have to do the right thing based on the evidence we have, even if it's not great evidence," said Tim Jones, the Tennessee state epidemiologist and a veteran outbreak investigator.

"You hate to hurt an industry and cause $100 million in damage. On the other hand, I don't think any of us could sleep if we … didn't say something and then a kid died the next day."

On Thursday, Robert Tauxe, the lead investigator for the CDC, said the government is less sure about the source of the outbreak than it was on June 7. The government added raw jalapeño and serrano peppers to its list of suspects last week.

Field investigators still have not found one salmonella bacterium of the type tied to the outbreak, despite thousands of laboratory tests on tomatoes, peppers and other salsa ingredients.

"The fact that we cannot prove that they were contaminated is going to stay with us forever," said David Acheson, the FDA's food-safety chief.

Tom Nassif, chief executive of the Western Growers Association, a powerful industry group, suggested agencies be required to find a piece of produce carrying the pathogen linked to an outbreak before they issue a major food-safety warning.

"If they're going to do that kind of economic damage to a commodity group, then they should have a very firm foundation for making that determination," he said.

Nassif's group and others are asking Congress to compensate farmers, packers and others who lost money following the tomato warning.

About 40,000 salmonella infections are reported in the United States annually, according to the Global Infectious Disease and Epidemiology Network. Between 20 and 40 deaths per year are blamed on the bacteria, according to the latest figures available. The CDC estimates as many as 1.2 million salmonella infections go unreported each year.

Nearly all strains of salmonella bacteria originated in the guts of animals. A vegetable contaminated with salmonella has come into contact with feces or feces-tainted water.

"One way or another, poop got somewhere it didn't belong," Jones said.

But finding evidence of that contamination on a piece of produce is often impossible.

Fresh produce has a short shelf life. In most cases, weeks pass before a cluster of illnesses is identified and linked to a possible culprit. Once investigators arrive at a grocery store or farm, often nothing remains of the fruits or vegetables likely to have caused the outbreak.

So public health teams are left to work from interviews with victims – whose memories are imperfect.

In May and early June, interview data pointed to three types of tomatoes: red round, red Roma and red plum. The FDA felt confident enough in that conclusion to issue a strong, nationwide alert on June 7.

Subsequent interviews with many more people in outbreak areas, however, pointed instead to hot peppers and possibly other salsa ingredients. But the new evidence isn't conclusive, either.

"Neither tomatoes nor jalapeños explain the entire outbreak at this point," said Tauxe, the CDC official.

The FDA's warning about hot peppers, reiterated Thursday, is weak. Only Americans with compromised immune systems are alerted to avoid raw jalapeño peppers or raw serrano peppers.

"That is a reflection of the certainty we feel about the issue," Tauxe said.

It's unusual, but not unprecedented, for the target of a food-safety investigation to change after a public warning has been issued.

During a multistate outbreak in 1996 of the intestinal parasite cyclospora, investigators first fingered California strawberries. A number of natural-gas industry executives, among others, had fallen ill. The executives remembered eating strawberries in a dessert served at a meeting in Houston.

The food-safety scare that followed cost the California strawberry industry $15 million to $20 million, according to media accounts at the time.

But as the outbreak spread and investigators interviewed more victims, it became clear not all had eaten strawberries. Other evidence also suggested another culprit. Three weeks after issuing the strawberry warning, health officials announced Guatemalan raspberries as the source of the outbreak.

These, it turned out, had been served in the Houston dessert as well – but the strawberries had been more memorable.

Call The Bee's Jim Downing, (916) 321-1065.