Safety Factors

Working with vacuum-packed foods increases the health dangers caused by anaerobic and facultative bacteria—that is, bacteria—that can grow without oxygen. Because cooking temperatures are so low, there is danger that bacteria will not be killed if cooking is not carefully done. Salmonella, E. coli, listeria, and botulism bacteria are the most serious risks.

For these reasons, chefs and health officials are especially cautious about sous vide cooking and have instituted strict guidelines. The following steps summarize the most important aspects of these safety rules:
  1. Know the rules for sous vide set up by your local health department, and follow them carefully. Health departments usually require that you establish a HACCP system for sous vide cooking. To satisfy HACCP requirements, you must keep detailed records of every step in the production process for each item, including cooking and storage times and temperatures.
  2. Use only the freshest, most wholesome foods from reputable purveyors.
  3. Chill all foods thoroughly before vacuum packing. If you sear a food item before packing, chill it after searing and before packing.
  4. After packing, cook the food at once, or immediately refrigerate it at 38°F (3.3°C) or lower—or, even better, freeze it.
  5. After cooking, serve the food immediately, or chill it as quickly as possible in an ice bath or a blast chiller.
  6. Thaw cooked food frozen in its package in the refrigerator.

Sous vide cooking involves complex procedures, and the above summary is only a short introduction to its techniques and safety factors. Entire books have been written on the subject, some of which are listed in the Bibliography. Later in this text, you will find recipes illustrating some of these techniques, including a recipe for long cooking of a tough meat, for short cooking of fish, meat, and poultry, and for cooking vegetables. Once again, these are only examples that can help you begin to understand the nature of sous vide.

Finally, using the proper equipment, especially a chamber vacuum packager and an immersion circulator, is important. Home-style vacuum packers might be useful for experimenting, but only a chamber packer can achieve the vacuum pressures chefs find they need. Furthermore, home machines are not able to pack liquids, so they can’t pack meats with marinades. Most important, precise temperature control is critical when you are cooking at such low temperatures, and you need appropriate equipment for cooking sous vide.