monitoring of edible oils quality in restaurants and fast food centers using peroxide and acid values

Continuous surveillance and monitoring of used materials in food processing is a tool for achieving to food safety assurance. peroxide and acid values are common indicators to detect fat oxidation, frequent and longtime heating and usage of edible oils in cooking or frying of food. this study aimed to quality assessment of used edible oils in restaurants and fast food centers (sandwich centers) of zanjan, iran by determination peroxide value (pv) and acid value (av). a total 60 oil samples were collected randomly from restaurants (27 samples) and fast food centers (33 samples) based on cluster sampling plan of the zanjan city. titration methods were used to determine peroxide and acid values according to iran national standards protocols no. 4179 and 4178. peroxide value in 22 (81.48%) and 24 (80%) of oil samples and acid value in 22 (81.48%) and 30 (90.9%) of samples taken from restaurants and fast food centers were higher than standard limit, respectively. present investigation has shown that high pv and av in used edible oils of many restaurants and fast food centers in zanjan, iran. high range of peroxide and acid values indicate an improper use of oils in food preparing centers and presence toxic compounds in used oils and foodstuffs which threaten food consumers' health. therefore, continuous surveillance and monitoring of restaurants and food preparing centers and training of chefs, food operators in order to apply proper methods of cooking and frying food is very important and necessary.