Though every meatloaf recipe has its own personality and quirks, they all have a few things in common -- including the fact that they should always be fully cooked. The ingredients that are consistent across recipes, such as ground beef and egg, mean you can't settle for an undercooked entree, or else you risk contracting a foodborne illness. While your recipe may provide an estimate based on factors such as weight, you should always check your meatloaf to make sure it's done.

Even though meatloaf consists primarily of ground beef, its cooking specifications are unlike other ground beef recipes, such as hamburgers. While you can cook food like a hamburger to a rare, medium-rare or medium temperature, your meatloaf shouldn't be served with any pink in the middle. This isn't just because of the risk of foodborne illness originating from the meat itself, though. Meatloaf is often made with binding agents like egg, which is just as important to cook thoroughly as the meat. If your meatloaf isn't brown all the way through the middle, it isn't safe.

The type of meat that you choose for your meatloaf can impact the amount of time it takes to cook -- and its quality when it's finished. Lean ground beef, for example, takes longer to cook than beef with a higher fat content, and it also tends to dry out more. For a relatively shorter cooking time and a moister finished product, choose ground beef with as much as 30 percent fat. With less than 20 or 15 percent fat content, your meatloaf may dry out from both the lack of moisture-trapping fats and the longer cooking time.

Meatloaf should cook at a temperature between 375 and 400 degrees Fahrenheit. This temperature ensures that the loaf cooks all the way through while developing a relatively chewy crust on the outside -- a staple of the dish. A two-pound meatloaf takes about one hour to cook, so if yours weighs in at 1.6 pounds, take it out of the oven after about 45 minutes to check whether it's done. It may require a little extra time, but you're better off checking it too soon rather than too late -- otherwise, it could be scorched on the outside and dried out on the inside.

Because of the fluctuations between recipes, ovens, baking pans and other factors, there is no fool-proof way of predicting the cooking time for your meatloaf, no matter how much it weighs. This doesn't, however, mean that there's no way of telling when it's done. When you pull your meatloaf out of the oven, take its temperature by inserting a meat thermometer into its center. If it's around 155 to 160 F, it's safe to serve. Let it sit for a few minutes so that its juices can settle before you slice it.