Sous vide

French for under vacuum, sous vide is a food-packaging technique pioneered in Europe whereby fresh ingredients are combined into various dishes, vacuum-packed in individual-portion pouches, cooked under a vacuum, then chilled. Sous vide food is used most often by hotels, restaurants and caterers, though it's expected to become increasingly available in supermarkets.

For more details see http://sousvide.wikia.com/wiki/Main_Page