If the ground beef is uncooked you can keep the uncooked ground beef in the refrigerator for up to 4 days at most.
If you want to keep the ground beef longer than 4 days you should freeze it instead and the frozen ground beef should last up to around 6 months to a year.
Ground beef that has gone bad will usually become slimy or have a bad smell to it and should be thrown out.
But as long as you use the ground beef within 4 days of it being refrigerated it should be just fine.