Background: Frying is one of the most popular methods of food preparation. Since in fast food restaurants the oil is heated for prolonged and repeated periods of time, toxic compounds in oils likely go up to very high concentrations. In this study, we investigated chemical quality of oils that was used for frying in fast food restaurants.
Methods: Oil samples were collected from 42 fast food restaurants located in Shiraz, Iran. Samples were obtained from oils that were being heated in fryers at the peak of fast food restaurant activity between 10:00 and 12:00 PM. Acid and peroxide values and total polar compounds were measured according to standard procedures.
Results: Acid and peroxide values of 27 samples (64.3%) were higher than the permitted values for oil health (Table 1). This number for total polar compounds was 19 (45.2%).
Conclusion: In many fast food restaurants of Shiraz, Iran, oils that are in use contain high levels of toxic materials that may imperil consumers as well as restaurant workers. Strategies that can be used by restaurant staff to improve the condition are discussed.