Yes- depending on the packaging. If it's in a plastic container that's vaccuum sealed it will stay good for 2 days. If it's in a styrofoam tray with saran-wrap covering- cook or freeze within 24 hours of purchase.
No, hamburger that is not cooked to 160°F could harbor pathogenic bacteria.
Providing it was properly stored in the refrigerator promptly after preparing, possibly yes. Seven days is a bit of a stretch though ... maybe five days would be a better max.
Assuming it has remained constantly frozen for the three years hamburger is probably safe to eat. But, it may or may not taste good.
No.
Yes, assuming that your refrigerator is set at 40°F. or colder.
Food left out of the refrigerator is okay to eat for about 2 hours. If the temperature is under 80 degrees. The longer a food stays in the danger zone the more risk you take eating that food. Foods should either be kept hot or kept cold before eating to be really safe.
Yes, it should be perfectly safe, if the bananas are not rotten.
To be safe you should cook it within 24 hours and then eat within 24 hours of cooking.
No. Stew left out overnight would not be safe to eat, covered or not - unless where it was left out was as cold as a refrigerator.
Only if the car was as cold as a refrigerator. Otherwise, the food would not be safe to eat.
If the sealed pan was kept in the refrigerator, it should be OK. If it was left out at room temperature, then it should be discarded.
Depending how the raw hamburger has been packaged and handled, it might not be safe to use. Only you, the consumer, can determine whether you should use it. If the hamburger has been handled and stored properly and looks, smells and feels acceptable, then it is probably OK to cook. Unless it has been stored in a super chill drawer, it is probably starting to turn. It may even have a vinegary fragrance or tang to it due to bacterial growth. You'll have to decide whether it is worthwhile using.