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.  These pouches have become increasingly available in supermarkets.   Watch out for high preservatives in grocery store products.  They are meant to last a shelf life akin to Superman.