Whether cooked in sauce or otherwise, ground meat such as meatballs should be heated to 160 degrees Fahrenheit, according to the U. S. Department of Agriculture. To check the internal temperature of a meatball, gently push a cooking thermometer into the center of one of the larger balls. If the thermometer doesn't reach 160 F after a few seconds, cook them for longer. Unlike meat cuts such as steak or chops, ground meat doesn't need a rest time after cooking.

Cooking meatballs directly in tomato or other pasta sauce is usually not the best or safest way to make a delicious dish. Instead, shallow-fry meatballs in a little hot oil. This helps sear the meatballs on the outside and prevents them from falling apart when heated in the sauce. This also helps avoid undercooked, pink meatballs -- particularly because you can check the meat before mixing the balls in with sauce.

Cooking times depend on the size of the meatballs. For example, UK TV chef Jamie Oliver suggests cooking small meatballs in a pan for eight to 10 minutes. He also recommends cutting one of the meatballs in half to check for any sign of pinkness before adding to the pasta sauce. Meatballs larger than a golfball may need 20 to 30 minutes to cook.

frozen meatballs need longer to cook, whether cooked in sauce or fried. Slow cooker recipes that heat the meatballs gradually in the sauce work for fresh and thawed meat only. Avoid frozen meatballs in slow cooker sauces altogether. If cooking in tomato sauce, or sauce with red coloring, it can occasionally make the meat look pink. In this case, always use a thermometer to check if the meat is ready.