Technically, adequately made LDPE and HDPE bags/containers are safe for food storage and consumption. Recycled materials and unsafe additives/colors, etc. must not be added.For instance, LDPE bags are more transparent in nature than HDPE, so it ideal for clear zip-lock sandwich bags. HDPE is tougher and opaquer (UV protection of sensitive foods), so used for milk bottles. Consider factors like barrier, toughness, seal ability before making your purchase.