I know this might not be a question to ask on here but was hoping maybe someone might be in the deep frying industry and could help since I've been on hold for over 1 hour and nothing yet.  Does anyone know how long oil can sit in a industrial fryer? 500gallons approx. If i use the oil to fry and then shut it down, do i have to clean it every night or is it possible to leave the oil in the fryer. Again I really apologize for asking a USDA related question. 
The actual USDA recommends that you let your oil cool down, strain it and store it in an air-tight, light-proof container if you plan on using it again. Refrigeration is not mandatory, but highly recommended.   These precautions are in place to prevent your oil from oxidizing and giving a rancid smell to your food.   165 degrees Fahrenheit is the minimal internal temperature your poultry needs to reach in order to be safe to eat, it has nothing to do with oil temperature in the fryer.  