Introduction
Coffee is one of the most widely consumed beverages worldwide, with an estimated annual intake of about 500 billion cups. Roasting is a key step in coffee processing that develops the desirable color, flavor, and aroma, but it also promotes the formation of acrylamide through the Maillard reaction. Acrylamide is classified as a probable human carcinogen and has attracted increasing attention due to its occurrence in a variety of heat-treated foods. Given the growing popularity of coffee among the Iranian population, determining acrylamide levels in espresso and assessing the associated health risks are of public health importance. Therefore, this study aimed to determine acrylamide levels in commercially available espresso coffees and assess the related cancer and non-cancer risks in adolescents and adults.
Materials and Methods
In this study, a total of 35 espresso coffee samples were collected from the market. Of these, 26 samples were obtained from coffee shops (ES-C), and 9 were prepared at home from commercial coffee powders using a household espresso machine (ES-H), following common local preparation practices. Acrylamide concentrations in all samples were determined using HPLC-DAD with a mobile phase composed of water/acetonitrile (97:3, v/v) at a flow rate of 0.7 mL/min and a detection wavelength of 202 nm.  The average daily intake (ADI) of acrylamide (μg/kg body weight/day) was estimated for adolescents and adults based on the measured acrylamide concentrations and the available consumption data. Health risk assessment was performed by calculating the margin of exposure (MOE) for carcinogenic effects, estimating the incremental lifetime cancer risk (ILCR), and evaluating the non-carcinogenic risk using the target hazard quotient (THQ). The obtained MOE values were compared with the reference value of 10,000. In addition, carcinogenic and non-carcinogenic risks were evaluated against internationally accepted benchmarks, including those established by the United States Environmental Protection Agency (USEPA).
Results and Discussion
Acrylamide was detected in all analyzed espresso samples. The concentration of acrylamide in ES-C ranged from 2.15 to 9.16 μg/100 mL and was consistently higher than that observed in ES-H, which ranged from 0.93 to 4.00 μg/100 mL. Despite the presence of acrylamide in all samples, the estimated dietary exposure via espresso consumption was relatively low. The EDI of acrylamide from espresso was calculated to be 0.004 μg/kg bw/day for adolescents and 0.007 μg/kg bw/day for adults. For all samples and both age groups, the MOE values were greater than 10,000, indicating a low level of concern and a low priority for risk management regarding carcinogenic effects. The incremental lifetime cancer risk attributed to acrylamide exposure from espresso consumption was estimated at 0.244 × 10^-5 for adolescents and 0.221 × 10^-5 for adults. Since both values were below the 10⁻⁵ benchmark proposed by the United States Environmental Protection Agency (USEPA), the associated carcinogenic risk was considered to be low. Non‑carcinogenic risk indices were 0.0019 for adolescents and 0.0026 for adults, clearly below the threshold of 1, suggesting that non‑cancer effects are unlikely at the observed exposure levels. For all evaluated parameters, acrylamide exposure and the associated health risks were higher in adults than in adolescents. This difference can be attributed to higher consumption rates and greater body weight-adjusted intake among adults.
Conclusion
This study shows that acrylamide was present in all espresso coffee samples collected from the market, with coffee shop espresso generally containing higher levels than household espresso coffees. Nevertheless, acrylamide exposure through espresso consumption alone does not appear to pose a serious health risk to the studied adolescent and adult populations. The high MOE values, low estimated cancer risks, and non‑carcinogenic indices well below 1 collectively support a low level of concern. However, espresso is considered only one contributor to total dietary acrylamide intake, as acrylamide can also be formed in other thermally processed foods. Therefore, evaluation of combined exposure from various dietary sources and further investigation of cumulative health risks are recommended to provide a more comprehensive risk assessment.