There are two sets of minimum temperatures at work here. The FDA Food Code (and CalCode in California) requires 155-deg. internal for ground beef. However, because meatloaf is a mixture of ingredients, it should be taken to 165-deg. or higher. I've noticed that most temperature charts designed for the home market, including those printed by supermarkets, add 5 degrees to the FDA minimums.
9/18/14 at 6:29pm