Material suggestions for Flexible food pouch

[doctorplastic]

I would appreciate some suggestions as to a suitable material for manufacturing a semi-flexible food pouch for containing liquidised food. The pouch material should be resistant to microwave heating, needs to comply with FDA directives, and needs to be resilient enough to be refillable. It also needs to facilitate the attachment/detachment of a rigid moulded lid at the open end of the pouch.

Any ideas?