Mineral oil hydrocarbons (MOH) are complex mixtures of saturated hydrocarbons (MOSH) which bioaccumulate in human tissues, and aromatic hydrocarbons (MOAH) which include genotoxic and carcinogenic substances. This work aimed to investigate these emerging food contaminants in basil pesto from the Italian market, and ingredient contribution to the final product contamination. Twelve market samples and 4 additional samples (and related ingredients) produced in a pilot plant, were analyzed by on-line high-performance liquid chromatography (HPLC)- gas chromatography (GC), preceded by matrix-tailored sample preparation. Method performance was good with recoveries from 94% to 109%, residual standard deviations (RSD) less than 10%, and a limit of quantitation (LOQ) of 0.5 mg/kg (for total MOAH). Vegetable oils, followed by cashews, which showed a similar contamination profile to foods transported in jute bags, were the major contributors to contamination, while cheese and basil contribution was negligible. Sunflower oil alone accounted for more than 80–85% of the total contamination. Samples from the Italian market had an average of 5.6 and 0.6 mg/kg of MOSH and MOAH, respectively, and a contamination profile that confirmed that the main contributors to total contamination were sunflower oil and cashews. Mitigation actions should be directed toward careful control of these two ingredients.
