RE: Use by dates?
Best before - means you can use after the date but it wont be at its best
Useby means what it says -useby or it will have started to spoil
If you did get sick eating past a useby date you have no comeback on where the food came from as you disregarded the instructions.
Personally If something is getting near its use by i will cook it and put it in the fridge which gives me another couple of days at least