Investigation of salicylic acid in milk in the Republic of Croatia: occurrence, exposure, and risk assessment*

Salicylic acid is a non-steroidal anti-inflammatory drug and plant hormone widely used in pharmaceutical, cosmetic, and medical applications. This study analysed its presence in cow's, goat's, and sheep's milk from farms in the Republic of Croatia, as well as in fresh pasteurised and long-life (UHT) milk from supermarkets. A total of 240 samples were analysed during 2023 and 2024. Sample preparation included hydrolysis, acetonitrile extraction, and solid-phase extraction (SPE) clean-up followed by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. Salicylic acid was detected above the limit of quantification (LOQ) in 47.9% of the samples and above the decision limit (CCα) in 21.7%. The highest concentration was found in cow's milk (411.3 µg kg^-1). No statistically significant differences were observed among cow's, goat's, and sheep's milk, or between fresh pasteurised and UHT milk. The estimated daily intake (EDI) values ranged from 0.004 to 0.64 μg kg^-1 bw day^-1, and the hazard index (HI) from 0.0006 to 0.10. The HI remained below 1 for all consumer groups, indicating no potential health risks.