Sifting through the hundreds of news reports on the current salmonella outbreak is like flipping the pages of a Sherlock Holmes story. From a mysterious onslaught of sickness and crack investigators following the contamination trail to pinpointing the Peanut Corporation of America as the culprit, this media mega-story gets more interesting with every page.

In November 2008, several reports of Salmonella Typhimurium were recorded across the United States and picked up by the Centers for Disease Control. By the end of month, forty-one cases had been reported. After the past year’s tomato- and jalapeño-related salmonella outbreaks, the media did not hesitate to jump on this story. As U.S. and Canadian authorities traced contaminated products back to Peanut Corp. of America, readers followed along, with articles regularly providing fresh insights to the evolving investigation—the infections, the lab tests (and cover-ups), the recalls, the Congressional hearings, Peanut Corp.’s decision to file for bankruptcy, impacts on food industry sales, soup kitchens and food pantries having to throw out tainted products. The coverage was widespread and gripping.

For all the excellent stories about the epidemiology, politics, and business of food, however, many reporters failed to proceed from whodunnit and where-they-dunnit to how-they-dunnit. Except for the initial news reports three months ago, most stories have omitted any quick, simple explanations about what salmonella is. And, ever since authorities identified Peanut Corp. of America as the source of outbreak, most articles have also failed to explain why the plant’s products are contaminated. As the story progresses, politicians and health groups are calling for better protections and inspection guidelines. The how is central to that effort.

Several articles have reported that inspectors found roaches, mold, and a leaking roof in the Blakely, Georgia and Plainview, Texas plants. A Los Angeles Times piece, published February 7, reported that inspectors at the Georgia plant found “roaches; mold on the walls and ceiling and in the storage cooler; dirty utensils and equipment used in food preparation; and gaps in the roof, allowing for wet conditions that could cause salmonella contamination.” But here’s the thing: salmonella does not come from mold or leaky roofs. Other articles in the Washington Post, Newsday, and the Chicago Tribune either make the wrong assumptions about the correlation between leaking water and salmonella or made no attempts to explain the basic science at all.

A dirty, poorly maintained plant might be disgusting, but dirt and disrepair don’t cause salmonella outbreaks.

Salmonella Typhimurium is an anaerobic bacteria (meaning that it does not live or grow in the presence of oxygen) that exists in the intestinal tracts of humans and animals, including birds. The bacteria can thrive in some animal species without causing any disease symptoms. Once inside humans, it can cause diarrhea, fever, and abdominal cramps. Humans usually become infected when they eat foods contaminated by animal feces.

The main salmonella sources at the Peanut Corp. of America plants were not mold or leaky roofs, but the bird feces littering the roofs, which was being washed into the plant during rainstorms. The press barely made the feces-salmonella connection even after the former Peanut Corp. of America Texas plant manager Kenneth Kendrick told “Good Morning America” that “Water, particularly anything leaking off a roof, and this is where things get a little disgusting, is bird feces washing in.”

As a result of this investigation, government officials and health groups are demanding revamped national and state inspection systems. In a story with such potentially far-reaching impacts, people need to know exactly what happened in the salmonella progression in order to react appropriately.

It is very important for the media to realize that correlation does not always imply causation. Despite Kendrick’s nationally televised explanation of the major contamination source, hundreds of news outlets failed to include the explanation in their articles and readers were left to make the connection. So, take out your freshman year Biology book. Call a scientist. Google salmonella. Make an effort to understand the science behind the subject of your reporting.

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Katherine Bagley is a science, environment and health journalist based in New York City. She is currently working as a reporter for Audubon Magazine.