Dietary Exposure to Nitrosamines via Fast Food Consumption in Tehran: An Analysis of Determinants and Public Health Implications

This study aimed to quantify N-nitrosamine concentrations in fast foods sold in Tehran, Iran, and to identify the key factors influencing their formation, in order to inform safer food production practices and reduce dietary exposure risks. A cross-sectional analysis was conducted on 120 fast food samples (burgers, sausages, and kebabs) collected from 40 outlets (20 international chains, 20 local vendors) between March and June 2025. Seven volatile N-nitrosamines were analyzed using gas chromatography–mass spectrometry (GC-MS). Data on cooking methods, meat percentage, sodium nitrite use, and storage conditions were obtained through structured questionnaires. Statistical analyses, including ANOVA and multiple linear regression, were performed to identify significant predictors. Sausages exhibited the highest total nitrosamine levels (10.78 ± 3.60 µg/kg), followed by burgers (7.88 ± 2.58 µg/kg) and kebabs (6.30 ± 2.15 µg/kg). Local vendors showed higher levels (9.45 ± 3.15 µg/kg) than international chains (7.25 ± 2.30 µg/kg). Cooking temperature (β = 0.412, p < 0.001) and sodium nitrite use (β = 0.387, p = 0.002) were the strongest predictors of nitrosamine concentrations, with grilling producing the highest levels. Elevated nitrosamine levels in Tehran’s fast foods, particularly sausages, highlight the need for regulatory measures to limit nitrite use and optimize cooking practices. Future research should address potential confounding factors, such as pH or storage duration, and explore natural inhibitors like ascorbic acid to further mitigate nitrosamine formation.