USE - BY & BEST BEFORE
Provided voluntary by the manufacturer to let you know how long the will remain at it's absolute best. The product is still edible after this date but the taste may decline.
Found on perishable like meat and dairy. This is a guide for stores to know how long they can display the product. You can eat the product beyond this date as long as it is stored properly.
SELL - BY
This is usually found only on baby food or other products the government regulates with regard to dating. Do not consume past this date.