Hi Richard, I'd just use it any way coz it doesn't know.
But seriously a month is here nor there if its still in a sealed pack, and TBH a lot of the "Best Before" date are made up by manufacturers they don't want you using older stuff they want you to chuck it and buy more. This doesn't apply to "Use By" dates though; Re sausages, milk etc. "Yuk".
Its all down to the natural degradation of the product and spray dried or dried stuff lasts a long time including Sugars, if kept sealed ,cool , dark, et al.
Tins are best -100yrs found on a US civil war boat -Perfect!
Hope this rests your mind.
Barnie.
