Background and Aims: Extensive oxidation as a dire consequence of oil overheating leads to increasing peroxides as well as volatile compounds. Such materials can cause free radicals in humans, body and consequently result in cancers, inflammatory diseases, and atherosclerosis. According to harms of hydrogen peroxide and overconsumption of fast food by people, it is necessary to determine health factors of it in terms of food safety. Materials and Method: in this descriptive study, according to standard number 493 of Institute of Standards and Industrial Research of Iran, 128 samples of the most heated oils in peak hours were prepared with census from all fast food shops of Ramsar town (64 cases) in 2016. Having transported samples to laboratory and determined peroxide number according to standard number 4179, samples were analyzed. Data were analyzed with statistical software SPSS version 20 through tests T and Mann–Whitney .Results: 46 samples (36%) of all were unusable and 82 samples (64%) were usable (p=0.012). Minimum number of peroxide was 1.2 miliequivalent per kilogram (MEq kg) and maximum number of peroxide was 62.5 MEq kg. Furthermore, there was a significant difference between usable and unusable oil samples in two shops (p≤0.001). Conclusion: Results revealed that peroxide concentration in most samples were more than permitted amount. Obviously, ways of using oils in studied shops were inappropriate. Therefore, it is suggested teaching owners of these shops and supervising them regularly owing to dire consequencesof high peroxide on health.
