According to the University of Minnesota Extension, it is not safe to leave food in the slow cooker with the power turned off. Once the food is done, serve it right away or, if you're not ready to eat yet, refrigerate it until everyone is ready to eat. When you're ready, reheat it; and do so in the microwave, oven or on top of the stove -- it is not safe to reheat food in the slow cooker because it may allow bacteria to multiply.

Keep your food refrigerated before you put it in the slow cooker. Don't allow uncooked food to sit at room temperature because this allows bacteria to grow. Since the slow cooker does not get hot very quickly, this can give bacteria even more time to grow before the food cooks. You can reduce this problem by using the slow cooker's high setting for the first hour of cooking, which allows the crock to heat up more quickly. Although it is tempting to stir your slow cooker meal while it cooks, avoid it unless the recipe specifically calls for it. Each time you lift the lid, the temperature drops in the crock. Your food will take longer to cook, and you run the risk of the food hitting a temperature where bacteria multiply.

After you are done eating, it is important to put the food away within two hours, says the Canadian Partnership for Food Safety Education. After being cooked in the slow cooker, your food may still be warm, even after two hours. It is safest to spoon hot leftovers into shallow containers to allow for rapid cooling, and to refrigerate right away. Refrigerating hot food in deep containers could allow the food in the center to remain warm enough for bacteria to multiply.

Allowing food to sit in the slow cooker for several hours could put your family at risk for developing food poisoning. Telltale symptoms are vomiting, diarrhea, nausea and stomach cramps. You may also develop a fever or muscle aches. If you or your children develop these symptoms, keep yourself hydrated by drinking plenty of clear fluids. Call the doctor if you experience persistent vomiting, can't keep down any fluids or if diarrhea lasts more than a couple of days.