(June 27, 4:29 p.m.) As the number of reported illnesses climbed past 800, public health officials acknowledged that the unidentified source of a Salmonella Saintpaul outbreak linked to fresh tomatoes could still be putting contaminated product into the marketplace.

“We’re still getting reports of people becoming ill,” said Patricia Griffin, chief of the enteric diseases epidemiology branch at the Centers for Disease Control and Prevention. “Whatever this produce item is, it’s possibly still out there making people sick.”

Griffin said during a June 27 media briefing that there were 810 reported illnesses in 36 states and Washington, D.C. The onset dates of the illnesses ranged from April 10 to June 15.

Griffin said it can take more than two weeks from the time of onset for an illness to be reported to public health officials. The outbreak is still ongoing, she said.

The FDA has advised consumers not to eat roma or round red tomatoes unless they are sourced from areas approved by the agency. The FDA dispatched investigators June 20 to Florida and Mexico after traceback led them to farms in those areas.

However, David Acheson, FDA associate commissioner for foods, has said that no growers have been implicated and contamination might have occurred somewhere else in the supply chain.

Acheson said June 27 that FDA has tested about 1,700 samples, mostly of tomatoes, and all had been negative. Investigators also are taking water and environmental samples from farms, packing sheds, repacking operations and distribution centers.

Acheson said up to 90% of tomatoes in the U.S. supply chain are repacked.

“It’s a very, very common practice,” he said. “It makes tracing extremely difficult.”

As an example, Acheson said some domestic tomatoes are sent to Mexico for repacking and are exported back to the U.S.

Acheson reiterated that investigators might never be able to pinpoint the source of the outbreak. He said contaminated product might still be entering the supply chain from a repacking operation or some other source.

“That raises questions about something that’s still out there,” he said of the June 15 onset date. “It doesn’t fill anybody with comfort at FDA or CDC that new cases are still coming in.”

Griffin said this is the largest salmonella outbreak that has been linked to produce.

The FDA based its consumer advisory on epidemiology. Victims reported having eaten tomatoes, but the agency has not yet had a positive test for Salmonella Saintpaul in tomatoes.

Griffin said that though there is a “strong association to consumption of tomatoes,” she is keeping an open mind about source of outbreak.

“It’s frustrating to all of us to be this far along in the investigation and not have an answer,” she said.

Griffin declined to comment on what other foods might be suspect, and Acheson downplayed the idea that something other than tomatoes could be the cause.

Contaminated tomatoes may still be in supply chain
David Acheson, FDA associate commissioner for foods, says repacking complicates traceback efforts. He says up to 90% of tomatoes in the U.S. supply chain are repacked.