Bioplastics based on potato starch not necessarily compostable

You may assume that bioplastics made from potato starch can be composted. However, that is not necessarily the case.

In the picture you see a supposedly biodegradable fork and spoon after 60-90 days in San Francisco's commercial composting operation (Picture from myplasticfreelife.com)

Taterware, the manufacturer of the items in the picture, states that its utensils are made from GMO free potato sources. But while the material used is purportedly a green one,  Taterware itself doesn’t claim all it’s products are compostable. They do make an ASTM D6400 compliant line, but these are visually almost indistinguishable from their non biodegradable varieties. As such,  it’s easy to see why commercial composters may be compelled to remove all utensils from the compost stream, because even when they are made from the same material, it’s no guarantee they are equally designed to break down. This identifies the other key problem, that  too many non-biodegradable  items are mis-sorted by consumers which commercial composters cannot recognize.