Is it safe to eat nuts after expiration date?
No I dont recommend eating anything after the Expiration date
Is it safe to eat canned food past expiration date if the can were exposed to summer heat and freezing in the winter?
That depends how long after the expiration, how it has been stored and the condition of the can. Usually, canned food has a "best by", not an "expiration". If the "expiration" is recent and the can has been stored properly and is in good condition, the contents could be safe. Whether or not to use it would be your decision.
If you are talking about shelf stable canned crab meat, the date on the can is likely the 'best by' date and not an expiration. If the can is unopened, has been stored properly and is not swollen or damaged, it is likely safe to eat, but the palatability of the crab meat will deteriorate over time. The processor will not guarantee the product beyond the recommended 'use by' date.
Possibly, but it is not worth the risk. Cheese tends to develop mold after it reaches the expiration date, and the mold is not always easily visible. The manufacturers put the expiration dates on foods for the safety of consumers, so please, don't ever eat any food past the expiration date - it simply is not worth the risk. Food borne illnesses kill many people in the US every year.
When the expiration date has passed on food or dairy products when it's still on the shelves of a supermarket, it should be considered to be unsafe for eating or drinking. In some cases a food label will say. "best to eat after the food opened 10 days or less " for example, this is an item purchased before its expiration date. Once it's opened the above notice on the label should be followed.