According to the Centers for Disease Control and Prevention, Norovirus is one of the most common causes of foodborne-illness in the United States. And the Mexican-food chain Chipotle is now facing a federal criminal investigation for an outbreak at a Simi Valley restaurant that sickened more than 100 customers and employees. This is just one of several instances of Chipotle customers getting food poisoning in various states. So what’s going on? Chipotle is supposed to be the healthy fast food.