The "best before date" represents the time when the product is past its best. It represents the quality of the item, not the safety of eating it.
When past the date, it does not mean the food is harmful. It just means the product might have lost some flavour or texture or colour. Therefore, the "best before date" is just a suggestion. It is only a guideline about the quality of the product. It does not have to be adhered to.
Hope this helps