Defrosting ground beef in the refrigerator is a timely process that takes a minimum of 24 hours for every 5 pounds of meat. If your meat isn't thawed and you're trying to get dinner on the table, take a shortcut by cooking the partially thawed hamburger meat. Although cooking meat from a semi-defrosted safe is generally safe, take certain precautions to reduce your risk of food-borne illnesses.
When cooking partially thawed hamburger meat, have a meat thermometer handy. Measure the internal temperature of the ground beef to determine when it reaches a safe temperature. The U.S. Department of Agriculture -- or USDA -- recommends a temperature of 160 degrees Fahrenheit for ground beef.
Cooking food from a frozen state increases cooking time by approximately 50 percent, according to the USDA. For example, if it normally takes 20 minutes for thawed hamburgers to be fully cooked, you'll need about 30 minutes to cook hamburger meat that is still frozen. If you are in a time crunch, finish thawing the beef in cold water. Submerge the meat while enclosed in a package in a pot of cold water. Small packages of hamburgers should finish thawing in less than an hour.
If you have portions of the hamburger meat that you do not plan to use, it is safe to refreeze them from a thawed or partially thawed state. Also, after cooking the meat, you may refreeze it to use at a later time. However, because the meat loses moisture during thawing, the quality of the hamburgers may be compromised.
Avoid thawing the hamburger meat at room temperature. Thaw meat in the refrigerator or in cold water where temperatures are below 40 degrees Fahrenheit. If ground beef is exposed to temperatures above 40 degrees Fahrenheit for more than two hours without cooking, this increases the risk of bacteria growth. Signs that the meat has spoiled includes an acrid smell and sticky texture on the surface of the meat.