Bacteria multiply rapidly in the Danger Zone — temperatures between 40 and 140 °F (4.4 and 60 °C). To keep bacterial levels low, store ground beef at 40 °F (4.4 °C) or below and use within 2 days, or freeze. To destroy harmful bacteria, cook ground beef to a safe minimum internal temperature of 160 °F (71.1 °C).hange the water every 30 minutes. Cook immediately. Do not refreeze raw ground meat thawed in cold water or in the microwave oven unless you cook it first. Never leave ground beef or any perishable food out at room temperature for more than 2 hours (1 hour at 90 °F and above).