Leafy Greens Cause the Most Illnesses—Mushrooms, the Least

Photograph by Phil Ashley

Sometimes a diet of Tang and chewing gum seems the only safe option left. A new Centers for Disease Control and Prevention study finds that leafy greens—for example, lettuce, spinach, kale, and arugula (or “rocket,” as some Canadians call it)—cause more illnesses than any other food. Anxious herbivores need not worry themselves sick, though: Mushrooms were associated with the fewest cases of illness among all foods.

Together, fruits, nuts, and vegetables accounted for 46.1 percent of food borne illnesses from 1998 to 2008. Leafy greens accounted for 2.1 million cases, or 22.1 percent of the total, often by carrying viruses. Fungi were responsible for only 4,542 cases, due mostly to toxins produced by the food and to chemicals such as pesticides.

People often cook mushrooms, rather than eat them raw, and they consume them less frequently than leafy greens. It’s also rare that people eat poisonous mushrooms, CDC spokesperson Candice Hoffmann wrote in an e-mail.

The study did not measure how much of each food is typically consumed. (This might explain why there were few incidents—only 9,097 cases—of illness associated with game such as venison and bear.) The average American eats only 4 pounds of mushrooms each year, compared to 30 lbs. of lettuce.

Also, greens such as lettuce and spinach cause illness more frequently because they are consumed more often, not because they are grown or harvested in a riskier way than other vegetables, says Scott Horsfall, chief executive officer of the California Leafy Green Products Handler Marketing Agreement, a program under the state’s Department of Food and Agriculture.

In fact, the problem with leafy greens has less to do with farming than with handling. Many were tainted with norovirus, which causes stomach flu, and “were most often contaminated during preparation or service by a sick food handler,” the report found. Infected persons are contagious “from the moment they begin feeling sick until at least three days after they recover” and can spread the virus through vomit and stool, according to the CDC.

Before sadistic meat eaters start chuckling at the fates of some health-focused, leaf-eating counterparts, they should consider this: While leafy greens may have caused the greatest volume of sickness, poultry accounted for the most deaths, at 19 percent. Pass the portobello mushrooms, please.

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