What is the shelf life of PHA?

I'm curious, can you elaborate on the shelf life of PHA? How long can it be stored for while maintaining its quality and efficacy? Are there any specific storage conditions that need to be met in order to preserve its longevity? I'm particularly interested in this information as it pertains to the food and pharmaceutical industries, where PHA may be used as a biodegradable packaging material or a drug delivery vehicle. I would appreciate any insights you can provide on this topic.