Dangers of PLA Containers Made from GMO Corn

Leaching from a container depends on a couple of variables related to solubility of the leachant in question: heat can promote leaching (the corn PLA is not recommended for temperatures above 110 so this is probably a significant factor) and the liquid into which the substance must leach has to be compatible and able to solubilize it (oil vs water vs ethanol etc). Gradients play a role in leaching, too.

Bt toxins are proteins. Get your kids to do a leaching project for the science fair, filling PLA containers with different liquids /at temperatures/ and measuring what is leached and whether Bt toxin is part of it. Bt toxin is not considered toxic to humans or mammals (allergy is a different matter). It's not the same as a chemical pesticide. But the transfection issues could be a health risk, if the gene was taken up by friendly bacteria that live in your gut, for example. That could upset your internal ecosystem, I'm guessing. There are a lot of different variations on the Bt corn. Some are not recommended for humans to eat. Whether they would be used in a package I dont know. How much Bt is present in the corn used, is another variable, unknown.

The sugarcane plastics sound like a tasty alternative. Not widely GMO afaik, and the packages are way more heat tolerant - even microwave.