This question already has an answer here:
When there is some food (like cheese or ham) that has roughly a week "use by" date, I assume that it's safe to eat it a day after it's "use by" date.
For other food that has approx. half year "use by" date (like olives in glass or pesto) I think it's safe to eat it for anything up to a month or so.
And for canned foods having years it should be safe to eat few months after "use by" date.
My thinking is that it's harder to pinpoint the exact date the further the date is in the future. I would even expect that "use by" dates are something around the half time the food is still actually edible.
Am I correct in this line of thinking? Do you know of any reliable resources on this? I couldn't find anything.