What is difference between best before date and use by date?
Yes I believe you are correct. It is important to understand the dates are guides and should be used along with common sense. For example chicken and a use by date is more prevalent than a packet of crisps and a best before date. Ignoring the date on the former could lead to food poisioning whereas the latter will only result in a soft crisp.
Both the terms are used by the food manufacturers only as a guideline by which time the food must be consumed. For example if a food article bears a date best before 11 May 2009 it means that it must be consumed well before that date. I doesn’t mean that exactly on that date the food becomes unfit for consumption. It also doesn’t mean that the food is totally consumable a day earlier. It only a cautionary indicator. If you find that a food reaches its expiry 6 months from the date of manufacture we must be cautious enough to consume it by say 4 months.