An investigation into whether tainted tomatoes caused more than 850 people to get sick from salmonella is broadening instead of narrowing, prompting consumers and food safety officials alike to express frustration today.
"The pace of this investigation has been frustratingly slow," said Dr. David Acheson, associate commissioner for food at the Food and Drug Administration, Tuesday.
Food safety officials with the FDA and the Centers for Disease Control and Prevention said salmonella has left 869 people ill since April, up from 851 illnesses recorded this weekend. They also said that while tomatoes are the "lead suspect," they aren't yet certain tomatoes are to blame for the illnesses.
"Before you can say it's an outbreak and stop eating tomatoes, there should be certain evidence that that's exactly true, and until that's done, they should reserve judgment," said Tom Nassif, CEO of the Western Growers Association in Irvine, Calif., Tuesday.
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Federal officials first announced the salmonella illnesses months ago, centering their investigation on certain types of raw tomatoes. Since then, food safety inspectors have traveled to tomato farms in Mexico and Florida as the number of sick people continued to rise.
But instead of homing in on what caused the illnesses over the past few months, inspectors now say that they aren't so sure that tomatoes are the culprit.
Several illnesses among people who ate at restaurants in Texas and other states have forced investigators to re-examine their initial assumptions, the CDC explained in a Monday update.
"These clusters have led us to broaden the investigation to be sure that it encompasses food items that are commonly consumed with tomatoes," the CDC update stated.
As a result, officials are retracing their steps and talking to sick people to find what else could be causing the illnesses.
Texas has seen the most cases of salmonella, with more than 300 people sick. New Mexico and Illinois have had reports of nearly 100 illnesses from the outbreak, according to numbers from the CDC.
In the meantime, tomato farmers want a congressional investigation into the matter, as the industry stands to lose hundreds of millions of dollars over the tomato scare.
"All of these people are losing money because of this blanket statement that tomatoes should not be consumed," Nassif said.
Acheson said Tuesday, "The investigation will continue to focus on the entire production chain, from farm to consumer."
According to the CDC, no deaths have been officially attributed to the salmonella outbreak, though a patient in Texas who recently died from cancer was also sick with salmonella at the time of his death.
Symptoms of salmonella include diarrhea, fever and abdominal cramps within one to three days of infection, the CDC said. The illness typically lasts for four to seven days.
Food safety experts are still advising people to limit the amount of tomatoes they eat, and to stick to types of tomatoes they've deemed salmonella-free. Those they've concluded are safe include cherry and grape tomatoes, and tomatoes sold on the vine.
ABC News' Brian Hartman and Randy Gyllenhaal contributed to this report.