A slow cooker is certainly convenient, but if not used correctly there is the potential for food-safety hazards. Temperatures between 40° and 140°F fall into the so-called “Danger Zone” since bacteria thrive in these temperatures. When using a slow cooker be sure to take precautions that keep food from being in the Danger Zone for too long.
Choose dishes with high moisture contents, such as soups and stews, for slow cooking. The moisture generates steam which facilitates cooking and helps raise the temperature above the danger zone quickly.
Do not put frozen ingredients in the slow cooker; defrost meat and poultry thoroughly in the refrigerator before slow cooking.
Refrigerate any prepped ingredients in separate storage containers prior to cooking. Do not refrigerate uncooked ingredients in the slow cooker insert because the cold insert will take too long to reach cooking temperature.
Cut meat and poultry into chunks or small pieces to ensure thorough cooking. Do not attempt to cook a whole chicken or large roast in a slow cooker. The slow cooker cannot heat the large piece of meat quickly enough to avoid a food-safety risk.
Don’t overfill your slow cooker. Fill it no less than half full and no more than two-thirds full.
If you’re cooking meat and poultry on low, the USDA suggests that you start the dish on high for the first hour, then switch to low for the remainder of the cooking time. However, since this may not always be practical, we advise you to bring liquids to a simmer before adding them to the slow cooker on low, thereby jump-starting the creation of heat.
Avoid lifting the lid during cooking because it can cause the slow cooker to lose heat and will also affect cooking time. Do so only toward the end of cooking to check doneness.
Do not reheat food in the slow cooker—it takes too long to reach a safe temperature. Use the stovetop or microwave for reheating. However, you can use a slow cooker to keep food hot up to 2 hours before serving.
Lastly, follow everyday food-safety procedures: Start with clean equipment. Keep all perishables refrigerated until preparation time. Place leftovers in shallow containers, so they will cool quickly, and then refrigerate within 2 hours.