I bought some Parmesan for risotto. But when I was in the supermarket I looked at the information on each of the different Parmesan options, (whole pieces, flakes and ready grated). They all say that when once opened, they should be used within 5 days, or within 7 days, depending on which one.
The only option that will last longer is a tub of 'grated hard cheese', which contains preservative in the ingredients, and lasts a month, according to the details.
I'm quite surprised that a rectangle of Parmesan doesn't last longer than that, if it's true. So I was wondering what other people do with all that Parmesan to eat it all within five days? Or should I just buy the generic tub of grated hard cheese that has preservative in it?
I'd steer clear of the little tubs of ready grated long life stuff if I were you it's vile. I just buy a normal wedge and keep it in the fridge till it's been used and that could be months. Apart from soft cheeses I never take any notice of sell by dates
It's laughable that it has been aged for 24 months and is then labelled that it must be consumed in a matter of days! It is hardly likely to become toxic or spontaneously combust once opened, a classic case of daft H&S replacing common sense.
I use my eyes and nose, and even then I trim off any mouldy bits should they appear.