Pan-frying and deep-frying have been very popular and ancient methods of food preparations for more than 4000 years. Pre-fried and fried food products like potato crisps, fish fingers or French fries have become a main component of our diet. It is estimated that the total usage of frying fats and oils in restaurants, commercial frying and households is about 20 million tons a year.

During the last international symposium on Deep Fat Frying in Germany in March 2000, experts reaffirmed that there are no health concerns associated with consumption of frying fats and oils that have not been abused during normal frying conditions. In contrast, used cooking oils, containing high levels of degradation products, lead to a loss of organoleptic quality and a decrease in the nutrition value in fried foods, and cause strong foaming. Consumers also sometimes suffer from gastrointestinal distress after consuming food fried with such oils. Attempts by some frying establishments to bring about savings in frying oil costs have resulted in various improper practices such as the over use of frying oils, frying for too long a time, and recovery and reprocessing of spent frying oil for use in animal and poultry feeds which led indirectly to the Belgian catastrophe in which animal feed based on spent frying oil became accidentally contaminated with industrial transformer oil containing PCBs and dioxin.