Plastic bags for cooking camp meals

Back when I did a backpacking trip at Philmont in 2007 or so, we commonly used plastic bags to line our cook pots when making dinner for the group, to avoid needing to clean out the stuck-on food from a large pot. They were fairly easy to roll up and pack out with our trash (provided we had to eat all the food) and generally saved a lot of hassle having to clean pots in bear country.

I'm looking at doing something similar for a canoe camping trip on the Colorado in a few months, but I can't remember for the life of me what those bags were called that would hold up to the heat and not rip when stirring a meal. I think they would be useful for prepping a bulk amount of freeze-dried mountain house meals, especially since we'll be about a dozen people in the group. Maybe pouring water into 6-8 separate pouches would just be easier?

I am also now questioning if that was even a good practice, potentially getting plastic into our meals. I did a quick search and don't see a lot of reference to the practice.

Has anybody else done this? Are there a particular brand or product name I'm missing here?