Stainless steel and glass containers are safest for storing foods and liquids.
Plastic containers may release harmful chemicals, such as Bisphenol A (BPA), when placed under heat stress or when scratched and damaged. These chemicals have been linked to health effects that include cancer and reproductive harm.
If you must use plastic containers, do not heat the containers. Instead, transfer food to a glass or ceramic dish while heating it in the oven or microwave. Only use plastic containers that are designated by the manufacturer as food-grade. For maximum safety, do not repurpose non-food-grade plastics to store food.