the skin of fish can be cooked at high temperatures after the sous vide to make the skin crisp. Safety Food safety is a function of both time and temperature; a temperature usually considered insufficient to render food safe may be perfectly safe if maintained for long enough. Some sous vide fish recipes, for example, are cooked below . People with compromised immunity should never eat food that has not been properly pasteurized. Women eating food cooked sous vide while pregnant expose themselves and their fetus to risk and thus may choose to avoid unpasteurized recipes. Clostridium botulinum bacteria can grow in food in the absence of oxygen and produce the deadly botulinum toxin, so sous vide cooking must be performed under carefully controlled conditions to avoid botulism poisoning. Generally speaking, food that is heated and served within four hours is considered safe, but meat that is cooked for longer to tenderize must reach a temperature of at least within four hours and then be kept there for sufficient time, to pasteurize the meat. Pasteurization kills the botulism bacteria, but the possibility of hardy botulism spores surviving and reactivating once cool remains a concern as with many preserved foods, however processed. For that reason, Baldwin's treatise specifies precise chilling requirements for "cook-chill", so that the botulism spores do not have the opportunity to grow or propagate. Pasteurized food can then be stored for up to two weeks around sealed within the vacuum pack. Exposure to air also inactivates spore growth. Endocrine disruptors Most plastics release estrogenic chemicals that act as endocrine disruptors when heated. The degree of danger posed is controversial. Also, some evidence shows that heterocyclic aromatic amines and bisphenol-A migrate from the plastic container into the food in sous vide cooking. Uses The sous vide method is used in many high-end gourmet restaurants by chefs such as Heston Blumenthal, Paul Bocuse, Michael Carlson, Thomas Keller, Grant Achatz, Ferran Adrià, Joël Robuchon, Philippe Rochat, Alessandro Stratta, Charlie Trotter, Michael Mina and Joan Roca. Amtrak also uses this method for meals served on their trains, including the Acela Express. Sous vide has become common on cooking TV shows such as Iron Chef America and Top Chef, and in restaurants such as Panera Bread. It has also been used to quickly produce significant quantities of meals for hurricane evacuees. Nonprofessional cooks are also beginning to use sous vide cooking. Initially, enthusiasts