I made mmf this week and I was wondering if I kept wrapped and in a ziploc bag if it could be used next week?

I would say absolutely! I had some left over and just put it in the microwave for 10 seconds to soften it up again...

just make sure that the air is out of the bag and if you double bag it that should really ensure that the air wont creep in....when I do this I never have to microwave it stays soft! I have had it stay this way way 3-4 weeks ......after a point I just throw it out but once I forgot and had some green for 4 months and it was still soft! When I found it I was like wow thats still here, I opened and tasted it tasted good but didnt want to chance so I threw it out...

Does anybody really no the shelf life....someone in a bakery would probably know the actual length it can be kept.

Great!