Here is a bit of information on "Best Before" dates.
I called the Health Department on Thursday about a store across the street from me that has probably 90% of their products on the shelf months after the "Best Before" date.
The Health Department told me that "Best Before" is not an expiry date and that the product does not cease to be edible/consumable as soon as the "Best Before" date has been reached.
The "Best Before" date is simply a guideline that manufacturers put on their packages to let the consumer know when the product is the freshest. It's still edible/consumable after that date, and therefore there is no law that says a store can't sell stuff that is beyond the "Best Before" date.
I frequently have eggs in my fridge that go weeks and months past the "Best Before" date, so I asked about eggs. I was told that eggs can be consumed months after the "Best Before" date provided that you have cooked them well. Cooking eggs well goes for fresh eggs too because raw or partially raw eggs can lead to Salmonella. However, if the egg smells bad, of course you wouldn't want to eat it, but if it looks ok and smells ok, it's fine to eat.
As I mentioned earlier, the Best Before date is simply a guideline that the manufacturer places on the package to let us know when it's the freshest. Months/years after that date it is probably still edible, but it's not the freshest. For example, cookies bought before "Best Before" date will still have it's proper texture IE: crunch or chewy. 8 months after that date they cookies are still edible, but the texture may have changed and won't be as crunch or chewy as they would be if they were fresher.
Tea is simply dried leaves in a bag and therefore do not go "bad", but they can become stale and lose their potency if they aren't kept in an air tight container. But they're still good to use