view current print edition




CDC study clears tomatoes as cause of 2008 salmonella outbreak

by Joan Murphy | February 23, 2011

WASHINGTON - It's the news the produce industry has been waiting to hear for years: Tomatoes were never the source of the Salmonella outbreak in 2008 but were mixed in with the Jalapeño and Serrano peppers, the items that ended up causing the outbreak.

Researchers at the Centers for Disease Control & Prevention have authored a long-awaited analysis of the 2008 Salmonella Saintpaul outbreak that is slated to appear in the March 10 issue of the New England Journal of Medicine.

The study, "2008 Outbreak of Salmonella Saintpaul Infections Associated with Raw Produce," combs through the results of the case-control studies designed to identify a food that was causing the outbreak that sickened at least 1,500 people and may have caused two deaths between April and August of 2008.

In the study, CDC researchers join the state outbreak team in determining that tomatoes were thought to be the vehicle because one of the epidemiological studies showed a strong association between illness and consumption of raw tomatoes. Tomatoes have been cited in past salmonella outbreaks. Another item that fueled speculation that tomatoes were the problem: new cases dropped once the tomato alert was issued.

The agency issued a nationwide advisory June 7, 2008, that not only warned consumers to avoid certain tomatoes but also devastated the tomato industry and left the produce industry questioning whether tomatoes were ever the source of the illnesses. It wasn't until July 9 that FDA issued an advisory for Jalapeño peppers.

The epidemiological studies may have identified tomatoes because they were often eaten with hot peppers and because they were more easily identified than peppers as ingredients, the study said.

In the meantime, tomato tracebacks "did not converge on any one geographic location, supplier or growing area, and the FDA analyses of tomato samples did not identify salmonella," the study said. "The results of multiple investigations indicate that Jalapeño peppers were the major vehicle for transmission, and Serrano peppers were also a vehicle."

"We think it's very important that the report finally shows tomatoes were not the cause of the outbreak," said Tom Stenzel, president and chief executive officer of United Fresh Produce Association. The study shows why tomatoes were suspected and why it wasn't really the case, he added.

"For the industry, it's a very, very big deal," said Mr. Stenzel, adding that there are still consumers and others who believe tomatoes caused the outbreak and that it's important to set the record straight.

The industry is not trying to "beat anyone up," he said, but it's an important lesson for experts who are faced with making a definitive call on an item without all the facts.

FDA conducted 12 tracebacks of raw Roma and red round tomatoes, and analyzed 183 tomato samples and 113 environmental samples at tomato operations in Florida and Mexico.

Investigators isolated the outbreak strain from agricultural water and Serrano peppers collected on a Mexican farm, and Colorado officials detected the outbreak strain from a Jalapeno pepper collected at the home of an ill consumer.