Contamination means exposing food to filth, toxic substances, manual contact during service or preparation if such food will not be subsequently cooked prior to service, rodent or insect contact or infestation, or any condition which permits introduction of pathogenic microorganisms or foreign matter. Potentially hazardous foods held at temperatures between 45 degrees Fahrenheit (7.2 degrees Celsius) and 140 degrees Fahrenheit (60 degrees Celsius) for a period of time beyond that required for preparation are considered to be contaminated. Sufficient hot and cold storage facilities are to be provided and used to maintain potentially hazardous foods at required temperatures during storage. Each facility is to have a thermometer, accurate to plus or minus two degrees Fahrenheit, indicating the temperature therein.