Many people ask why grocery stores like Amazon do not take back these bags and reuse them. There are a few reasons:

• Hygiene - used bags may not be clean. Even bags that don't have food waste may be moldy because, in the tropics, even just condensation can encourage the growth of mold. 
• Cost of sterilisation. Returned bags would need to be sterilised. it is unlikely the grocery stores have such facilities and doing so might not only be expensive but could damage the bags making them less suitable for reuse.
• Cost of logistics. Collecting the bags back and getting them to sterilisation facilities would cost money and this expense would likely have to be passed on to customers

Are these problems impossible to solve? Certainly not. But they would cost money and grocery stores are under no pressure to reduce this waste. It is therefore, for now, up to you as a consumer, to figure out how to minimise the impact of these bags.

The easiest way, of course, is to avoid them altogether by doing your grocery shopping at a physical store!

^{Wrapping a present with an Amazon cold bag and some ribbon saved from a past gift.}