The aim of the study was to contribute to scarce literature data on the content of selected vitamins and iodine in mare’s milk. The study focused on the content of selected lipophilic vitamins (A, E), hydrophilic vitamins B1, B2, B6) and iodine in milk samples obtained from 8 mares during 6 months of lactation. The content of micronutrients was evaluated according to the stage of lactation. Vitamins B2 and B6 were determined using ion-pair reversed phase high performance liquid chromatography with fluorescence detection, vitamin B1 by fluorescence detection by reversed-phase liquid chromatography, vitamins A and E by the ultra-high performance liquid chromatography method with ultraviolet and fluorescence detection and iodine by the spectrophotometric method. Mean concentrations of vitamins A (0.06 ± 0.08 mg/l), E (0.083 ± 0.14 mg/l), B1 (256.24 ± 44.19 µg/l), B2 (111.40 ± 81.88 µg/l), B6 (0.30 ± 0.12 mg/l) reached lower values in mare’s milk compared to cow’s milk. The mean value of iodine in mare’s milk reached 44.48 ± 54.45 µg/l. Lactation stage proved to be a significant factor for vitamin B6 and iodine.

Yoghurts from cow, goat and sheep milk were produced and stored under defined conditions to monitor the influence of various factors on the benzoic acid content as determined by Ultra High Performance Liquid Chromatography (UHPLC). The highest level of benzoic acid was found in sheep yoghurt (43.26 ± 5.11 mg kg−1) and the lowest in cow yoghurt (13.38 ± 3.56 mg kg−1), with goat yoghurt (21.31 ± 5.66 mg kg−1) falling in between. Benzoic acid content did not show statistically significant variation until the second and third weeks of storage, and the dynamics of this variation varied depending on the type of yoghurt. The yoghurt culture containing different strains of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus also affected the contents of benzoic acid. Further, the different storage temperatures (2 and 8 °C) as well as the temperatures used to milk heat treatment before yoghurt production (80, 85 and 90 °C) affected the amount of benzoic acid in different types of yoghurts.

In this study, we determined four sulfonamide compounds (sulfadiazine, sulfadoxine, sulfamethoxazole, and sulfathiazole) in honey marketed in the Czech Republic (Brno). The content of these compounds was monitored in 50 honeys with different botanical and geographical origin. Preanalytical treatment included acidic hydrolysis with 10% trichloroacetic acid (TCA) and double extraction with acetonitrile and dichloromethane. Chromatographic analysis was performed by ultraperformance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) using a triple quadrupole (QqQ) in positive ionization mode (ESI+). For separation, the mobile phase was a 0.05% aqueous solution of formic acid (A) and 0.05% formic acid in methanol (B) with a gradient elution of 0–3 minutes: 10% B; 3–3.6 min: 90% B; and 3.6–5 min: 10% B, flow rate 0.30 ml/min. Three positive samples (6%) were found containing sulfadiazine (232.88 and 618.87 μg/kg) and sulfamethoxazole (62.64 μg/kg). According to the country of origin, two of these honeys were from European Union (EU) countries, and one was labeled as a blend of honey from EU and non-EU countries.