As discussed in the Dev Blog's post on the new Experimental Changes, my suggestion to solve the problem of having stackable food within the new system of food spoilage: I would think one solution to supporting food spoilage and keeping stackable amounts would be as it is implemented in Don't Starve. That is, an indicator bar that shows an 'average' level of freshness/spoilage in the stack, and you by default consume the least fresh item first. So each individual item could still have a freshness level, but still be stackable together with others of different levels. Stack splitting could break stacks apart, so you could also dump the least fresh half of the stack, etc.
