The salmonella outbreak that began in April and was linked to raw tomatoes was the largest of about a dozen such outbreaks since 1990, sickening more than 800 people in 36 states and the District of Columbia as of late June.
The outbreak involved consumers of raw red plum, red Roma or red round tomatoes suspected of carrying the rare "saintpaul" strain of salmonella bacteria. As many as 20,000 cases of illness may have gone unreported, according to the Centers for Disease Control and Prevention. News of the outbreak prompted many consumers, restaurants and markets to shun tomatoes. A Food and Drug Administration (FDA) probe eventually focused on tomatoes grown in Mexico and Florida, though they could have become contaminated almost anywhere from field to market.
Salmonella bacteria normally inhabit the digestive tract of wild and domestic animals; when people ingest the bacteria, symptoms can range from cramps to diarrhea. A common source of produce contamination is runoff waste from livestock and poultry farms. Salmonella that infect a tomato blossom can flourish inside the growing fruit. The bacteria can stick to the skin or seep inside a harvested tomato through the stem scar if the water in which it's rinsed harbors the pathogen and is colder than the fruit itself.
Consumers can't be blamed for feeling alarmed. There has been a rise in outbreaks linked to tainted produce, with 639 between 1990 and 2004, according to the Center for Science in the Public Interest. Some of that increase is due to better monitoring, but industry watchdogs say it also reflects lax oversight by the FDA, which regulates produce. In June, a Government Accountability Office report faulted the FDA for not strengthening food-safety programs. The FDA says it doesn't have the people or resources to keep tabs on every farm and shipper. In 2007, the agency launched the Tomato Safety Initiative in Florida and Virginia, areas linked to previous outbreaks.
Big produce growers estimate the outbreak may cost the industry $100 million. Meanwhile, advocates of locally produced food say the crisis only underscores the dangers of the industrialized food supply. In any event, there's reason to believe this summer's outbreak won't be the last. "Zero risk in an open environment like a field isn't really realistic," says Michelle Smith, a scientist in the FDA's food safety division.