Temperature Control This section is about how to kill germs with heat during cooking and how to stop their growth by keeping the food hot or cold. This is called temperature control, and you need thermometers to check food temperatures. There are special thermometers to check foods; there are also special thermometers to check refrigerator temperatures. The "Danger Zone" Bacteria, or other germs, need time, food and moisture (or wetness) to grow; but they won't grow when the temperature of the food is colder than 45º F (7º C) or hotter than 140º F (60º C). The temperatures in between 45º and 140º are in the "Danger Zone." Keep potentially hazardous foods out of the "Danger Zone!" For example, when food is left in the "Danger Zone", bacteria can grow fast, and make poisons that can make your customers and family very sick. Preparing Food
  • Wash your hands.
  • No barehand contact. Use barriers such as tongs, papers, spoons or gloves to prepare and serve ready-to-eat foods.
  • Get the food to be fixed from storage, the stove, the cooler or freezer. Take a little food out at a time, and keep the rest hot or cold until you are ready to work with it. Prepare potentially hazardous foods just before you need them.
  • Don't let the temperature of the food stay in the "Danger Zone."
Cooking Food Use a metal stem thermometer to check temperatures while cooking food to make sure that it gets done all the way inside. Different foods have to reach different temperature degrees to be done or safe. The metal stem thermometer measures the inside, or internal, temperature of the food. A thermometer that works best shows a range of 0° F to 220º F (0º C to 104º C). The only way you can be sure that the food is cooked enough is to use a metal stem thermometer placed in the center of the food, even if you also use a thermostat to control the temperature in the oven. When is the food cooked safe? Here are a few examples of potentially hazardous food and how hot they must be to be safe. They can be hotter, but they must be at least this hot to kill germs:
  • Poultry and Stuffing: 165º F (74º C)
  • Pork: 150º F (66º C)
  • Beef, Lamb and Seafood: 140º F (60º C)
  • Rare Beef: 130º F (54º C)
  • Hamburger (ground beef): 155º F (68º C)
You must place the thermometer in the thickest part of the meat or in the center of the food to get a true reading. (Do not touch a bone with the stem of the thermometer.) All poultry, all food made from poultry, all stuffed meats, and the stuffing in them must reach 165º F or hotter to destroy Salmonella and other bacteria. Hamburger (ground beef) must be cooked to 155º F. This includes all kinds of hamburger such as taco meat and meatloaf, as well as hamburger patties. Pork and all foods made from pork must cook to at least 150º F to prevent trichinosis, a very serious illness. Fish, seafood's, all foods made with seafood, and all other meats, such as beef and lamb, must be cooked to 140º F or hotter to kill the bacteria that cause foodborne illness. Some people like rare beef, and this is the one meat that can be cooked to only 130º F if it is served right away. No raw meat is really safe to eat. Never cook large roasts, turkeys or stuffed turkeys while they are still frozen. Their big size keeps the insides from cooking to a safe temperature. You must thaw them first so the heat can reach the center of the meat faster. Microwave ovens do not cook evenly; you must stir and turn the food while it cooks to make sure it cooks to the same temperature in every part. Check the food with a metal stem thermometer before you serve it. (Do not keep the thermometer in the food while it is cooking in the microwave oven.) How cold is cool? How hot is warm? Between the time you cook the food and you put away the cooked food in a cooler or freezer, its temperature can fall into the "Danger Zone." You will learn about how to keep cooked foods hot, hot holding, and how to reheat cold food. You will also learn how to get cooked foods cool, and how to keep food cold, cold holding. We begin with cooling hot food the right way. Cooling You always take a chance when you have to cool down food. The best way to have safe food is to make it fresh each day, just before you serve it. If you have food that is leftover or made in advance, you must cool it and store it safely. The first rule to remember about cooling: Cool hot food as fast as you can to 45º F (7º C) or below, past the "Danger Zone." Food that is not cooled fast enough is one of the leading causes of food borne illness. Cooling solid and soft foods Here are the six steps to cool solid and soft foods such as meats, refried beans, rice, potatoes, casseroles, stews, chili and thick soups or chowders:
1. Wash your hands. 
2. Before you put away any food, you must place it in shallow metal pans, with the food no more than 2inches deep. For very thin soups or stocks you may cool foods in pans 4 inches deep. 
3. Cut large roasts and turkeys into pieces no larger than 4 pounds. 
4. Put all meats and other hot food in the cooler or refrigerator as quickly as you can, right away; do not let the food sit at room temperature for more than 30 minutes. 
5. Do not stack pans; leave space for air to move around them.
6. Wait until the food has cooled to below 45º F before you cover it. 
Cooling liquid foods When you cool thin soup, sauces and gravy, you can use shallow 4-inch metal pans, or you can use the ice and water method, called an "ice bath". Remember, you want the food to cool as fast as possible to below 45º F. For shallow pan cooling, quickly put the hot food in metal pans that are wide with low sides; the food must be no more than 4 inches deep. Do not cover the food until it has cooled to 45º F in the refrigerator. It may be hard to carry a shallow pan with thin soup in it. The ice bath method works well for this job. Here are nine steps you take to cool food with an ice bath:
1. Wash your hands. 
2. Close the drain in a large sink. Place the metal pot or pan of hot food in the sink. 
3. Fill the sink with ice up to the level of food in the pot. 
4. Add cold water to the ice. 
5. Stir the soup or sauce often so that it cools all the way to the center.
6. Add more ice as the old ice melts. 
7. Check the food temperature with the metal stem thermometer. (Clean the thermometer stem after each use.) 
8. Be sure you have cooled the food from 140º F to under 45º F in less than 4 hours. 
9. Put the cooled foods into the refrigerator or freezer. 
Each refrigeration unit, cold table or cooler must have its own thermometer that gives a true measure of how cold the air is, but you must also check the food with a metal stem thermometer. Air in the cooler must be able to move around the food, so the pans and dishes need to have space between them; do not crowd them. Cold holding For cold holding, do not let food stand at room temperature because that will allow germs to grow. Store foods in a refrigerator, refrigerated display case, in ice, or other approved method. Always cold hold foods at 45° F or less. Fish, shellfish, poultry, milk and red meat will stay fresh longer if you cold hold them below 40° F (4° C). Use the metal stem thermometer to check the food in cold holding, for example, in salad bars, areas where you prepare food, and in coolers. If you use ice to keep the food cold on a salad bar or food display, be sure that the ice comes up to the level of the food that is in the pan or dish. Food must be colder than 45° F when you put it in the ice. Cold hold foods at 45° F or less. Thawing frozen food There are only three safe ways to thaw foods, and you must plan ahead to allow enough time to do it right:
1. Thaw food in the refrigerator; it may take a few hours or a few days. This is the best and safest way. Be sure to put meat in a container to catch the meat juices and to keep them from dripping on the food below.
2. Hold the food under cool, running water, never under warm or hot water.
3. In a microwave oven; you must then cook it or serve it right away. 
Never thaw food at room temperature, on a counter or in warm water. These methods let harmful bacteria grow to high numbers (the "Danger Zone"). Some special rules for cold salads and sandwich spreads You have learned about potentially hazardous food, and how the bacteria grow very easily in them. These foods must not be left at room temperature for even a short time. Foods like potato salad; pasta or macaroni salad egg salad and chicken salad has to be cold enough to keep germs from growing. When you make these foods, start with cold ingredients.
  • Wash your hands before handling the salad ingredients.
  • Make cold salads with cold cooked foods such as potatoes, pasta, chicken and eggs; all ingredients should be chilled to 45° F. 
If you wonder about keeping something cold, keep it cold while you check with a supervisor, the boss or the Health Department. Hot holding After the food is cooked and ready to serve, keep it warm enough to stop any germs from growing. There is special equipment for this. You must turn on steam tables, soup warmers, and heated surfaces before you need them so that they will be hot enough when you put the cooked food into them. Set the temperature control a little above 140° F, and then check the food with your metal stem thermometer to make sure the food stays at least at 140° F at all times. Stir liquid foods (like soups and gravies) so they don't get cold on top. Covers on the pans will help to keep the heat in and the food warm enough. Do not try to heat cold foods in these warmers. Hot hold food above 140° F. Reheating Food that is cooked and then cooled may need to be heated again. When you must reheat food, do it very quickly (within one hour) to 165° F (74° C). The right way to do this is on the stove burners, or in microwave ovens, convection ovens, or double boilers. Do not use anything that will heat the food slowly, because it takes too long to pass the "Danger Zone." Stir the food to be sure that all parts of it are hot. Then use your metal stem thermometer to check the temperature. Reheat foods to 165° F. What about food left at the table? When a customer leaves food on a plate or at the table, you must throw it away. If you have food like chips, rolls and bread and some of it is left over, you cannot serve it again. Unopened packages of crackers, jelly, candy or sugar may be served again. When the equipment breaks down or power goes off If something goes wrong with the stove, the refrigerators, the freezers, the steam tables, salad bar or display coolers, any equipment that keeps the food safe to serve, you must think and act quickly:
  • Be sure potentially hazardous hot foods stay hot (at least 140° F or more).
  • Be sure potentially hazardous cold foods stay cold (at least 45° F or colder). 
If a refrigerator does not work right, the temperature of the food in it can reach the "Danger Zone." Before you move the food to another cooler check its temperature with the metal stem thermometer. If it is still colder than 45° F (7° C), move it quickly to a cooler or refrigerator that is OK. If a freezer lets food thaw, check the food temperature with a metal stem thermometer. You can prepare the food, if it is still colder than 45° F. If hot holding equipment like a steam table or soup warmer fails, measure the temperature of the food it was holding. If the food is still hotter than 140° F (60° C), you have two choices:
  • Move the hot food to equipment that is OK and that will keep it hot.
  • Cool the food quickly using shallow metal pans or an ice bath.
You must throw out food that has gotten warmer than 45° F or cooler than 140° F. Do not serve it and do not give it to staff, family or shelters. Call your local Health Department office for help and advice. All information is general in nature and is not intended to be used as a substitute for appropriate professional advice. Source: Public Health - Seattle & King County Website