Sell by is entirely unrelated to quality though. It's just how often they think they can get away with. Like the recommendation on a box of baking soda... Put it in your fridge and change it every 30 days. No thanks.
Pretty sure that’s the recommendation to deodorize your fridge, not related to the baking soda’s shelf life. The other side of the box says “keep in a cool and dark place”.
It does seem to go “flat” after a few months regardless, even when the expiry date is 2 years in the future.
I think it all makes sense when you consider that the sell by date is the date at which they’ll stop accepting responsibility. And the “best before” dates are just guidelines.
