This has been looked into but not very extensively due to the carbonation levels of the product. This is why most of the packaging is rigid. A bag in the box concept would have issues since you would have expansion thus possibly burst. Another issue you would face is refrigerated transport. Since the product is non-pasteurized, it would require a constant cold environment to prevent spoilage.
Scott Zuhse, Instructor
Micro Matic Dispense Institute