When I buy spinach from the supermarket, it comes in a sealed plastic bag. There is always quite a lot of moisture inside the bag on the leaves. I used to find that spinach would last about 3 days in the fridge inside this bag, and then go mushy and bad.
I realised recently that the moisture is the problem. If I open the bag and spread the spinach out to dry for a couple of hours before putting it in the fridge, I find it lasts for up to 2 weeks. Given that the spinach lasts so much better this way, it seems strange to me that the supermarket does not put holes for ventilation in the bag, to keep it from getting so wet.
So, why does spinach from the supermarket come in an airtight bag?
(I live in the UK, and have only ever seen spinach in bags like this. I would also be interested to hear if people have experiences of different types of spinach packaging in other places)