What does “sell by” really mean when it’s stamped on the canned goods and perishable foods we buy?

On most dairy and processed foods, the freshness will remain several days after the given date, particularly if they have not been opened.

Most canned goods have a shelf life of several years stamped on their tops. When that date has passed, toss. They mean what they say. Also, discard cans with dents. If you find the dent when you come home from the store, take it back to replace with a perfect can.