Veggies are great for you, so long as they're clean first.

Each year, one American in six gets a case of food poisoning. Now, the Center for Disease Control has given us some new information on which foods seem to be causing the problems. Surprisingly, the single most common cause are leafy green vegetables, fruits and nuts.

The single most common place for contamination of these foods is in restaurant kitchens. One contaminated food handler with bad hand-washing habits can spread norovirus to dozens or even hundreds of people.

The second most common source of contamination is your own kitchen. They recommend that you be very careful if you use a cutting board for meat or poultry and then follow that up with the vegetables on the same counter or cutting board. Fix the vegetables first, then handle the meat. Meat and poultry do cause illnesses. But because people are aware of that risk, they tend to be more cautious in food preparation and cooking.

So the surprising take away is that those fruits and vegetables are healthy only as long as they’re clean.