Aluminium is used for packaging as it is highly malleable: it can be easily converted to thin sheets and folded, rolled or packed. Aluminium foil acts as a total barrier to light and oxygen (which cause fats to oxidise or become rancid), odours and flavours, moistness, and germs, and so it is used broadly in food and pharmaceutical packaging, including long-life packs (aseptic packaging) for drinks and dairy goods, which allows storing without refrigeration. Aluminium foil containers and trays are used to bake pies and to pack takeaway meals, ready snacks and long life pet foods.
Aluminium foil is widely sold into the consumer market, often in rolls of 500 mm (20 in) width and several metres in length. It is used for wrapping food in order to preserve it, for example, when storing leftover food in a refrigerator (where it serves the additional purpose of preventing odour exchange), when taking sandwiches on a journey, when baking, or when selling some kinds of take-away or fast food. Tex-Mex restaurants in the United States, for example, typically provide take-away burritos wrapped in aluminium foil.