By Annys Shin
Washington Post Staff Writer
Saturday, June 28, 2008
Tomatoes carrying a rare form of salmonella that has sickened more than 800 people may still be on the market, federal officials said yesterday, two weeks after they first warned consumers about the risk.
Investigators are considering the possibility that other produce may be spreading the bacteria.
"We continue to see a strong association with tomatoes, but we are keeping an open mind about other ingredients," said Patricia Griffin, a top epidemiologist with the Centers for Disease Control and Prevention.
The FDA has not changed its guidelines that it is safe to eat Roma, red plum and red round tomatoes not attached to a vine that were grown in certain areas. All cherry tomatoes, grape tomatoes and tomatoes attached to the vine are also okay. (For a list of safe areas, go to http://www.fda.gov.)
A total of 810 people in 36 states and the District have fallen ill from the bacteria known as salmonella saintpaul. The last confirmed illness began June 15. Symptoms include bloody diarrhea, abdominal pain and fever.
Many of the cases date to mid-May, and public health officials had previously attributed the surge in the number of illnesses over the past week to states paying closer attention to salmonella cases and confirming old ones.
With reports of more recent cases coming in daily, investigators are questioning some of their working assumptions about the likely source of the outbreak.
"We have to re-examine the whole thing," David Acheson, a top food safety official with the Food and Drug Administration said. "We are concerned there is something out there still exposing people to this salmonella saintpaul strain."
The FDA issued a warning about tomatoes more than two weeks ago. The warning was based on interviews with people who had gotten sick. Many had eaten tomatoes in dishes such as salsa or guacamole.
"Nothing that Dr. Griffin said indicates that we should be taking a serious look at anything else, but rightly that question is being asked," he said. "We need to be looking at all possibilities."
Investigators have focused their attention on Southern Florida and Mexico, the main suppliers of tomatoes to the United States when the outbreak began in mid-April.
Teams including microbiologists and other experts have spent the past week in both places, scouring farms, packing sheds and warehouses for evidence of the outbreak strain. They have collected more than 1,700 samples from fields, irrigation wells and storage containers, Acheson said, but so far none have tested positive.
Acheson said the investigation has proved especially difficult because of the timing of the outbreak and a common industry practice called repacking. The illnesses began just as the main source of tomatoes shifted from Mexico to Florida.
After they are picked, tomatoes are often repacked to meet the customer specifications. In the process, tomatoes from many farms are combined, making it harder to trace a shipment to a particular restaurant, for example, back to where it was grown.
In the spring, tomatoes from Mexico are shipped to Florida for repacking and vice versa. Acheson said they have no evidence linking the outbreak to the mingling of tomatoes from those places.