2. Chipotle closes 43 restaurants following E. coli outbreak

Chipotle Mexican Grill temporarily closed 43 restaurants in the Pacific Northwest in November after more than 20 people became ill with E. coli. The case count rose to as many as 53 people in nine states. In December, the Centers for Disease Control and Prevention began investigating another, more recent outbreak of E. coli linked to the burrito chain that resulted in five illnesses in three states. Read the full story.