The use of plastic bags is, of course, to store foods. However, using plastic
bags for boil-in-bag cooking (picture above) is the recent trend,
which foods are packed in plastic bags and boiled. In Japan the cooking
method is called "pack cooking" or "pouch cooking".
Our bags endure temperatures from -30℃ (-22℉) at lowest to 110℃ (230℉)
at highest, so this is the best choice for it.
Warning: when you try this, please lay down a heat-resistant dish and don't
let bags directly touch to pots.