Food came from an unapproved source, was missing required date marks or labels, or was past its use-by date. Knowing where food came from and how old it is helps prevent illness.
Food was not kept cold enough, hot enough, cooled fast enough, or cooked or reheated to the right temperature. Bacteria grow quickly in the "danger zone" between 41°F and 135°F, which makes this one of the most important food-safety checks.