Determination of Antibiotic Residues in Milk

Milk and dairy products are of great importance from the perspective of food safety, and the presence of antibiotic residues in their composition may pose a potential risk to human health. The widespread therapeutic use of antibiotics in livestock practice can lead to the occurrence of these residues in milk when withdrawal periods before milking are not properly observed. Therefore, the detection and quantitative assessment of antibiotic residues in milk is considered a relevant scientific problem.

This study was designed as an experimental laboratory investigation in which 30 raw milk samples obtained from different sources were analyzed. High-performance liquid chromatography (HPLC) was applied as a confirmatory method for the detection and verification of antibiotic residues. Within the study, antibiotics belonging to the β-lactam, tetracycline, and sulfonamide groups were identified on the basis of retention time agreement and chromatographic peak characteristics, and their concentrations were calculated using calibration curves. The obtained results were compared with internationally accepted maximum residue limits (MRLs).

According to the analytical results, antibiotic residues were detected in 60% of the milk samples (18 samples), while in 4 samples (13.3%) the antibiotic concentrations were close to or exceeded the MRL values. The HPLC method demonstrated high sensitivity, selectivity, and repeatability, confirming its reliability for quantitative determination of antibiotic residues in complex matrices such as milk.

The novelty of this study lies in the quantitative assessment of antibiotic residues in milk under local conditions using a modern confirmatory instrumental method and in the evaluation of milk safety by comparing the obtained data with international MRL requirements. The results scientifically justify the need to strengthen veterinary control and introduce regular laboratory monitoring throughout the milk production chain.

Antibiotic residues, milk safety, high-performance liquid chromatography (HPLC)

Reig, M., Toldrá, F., & Mora, L. (2014). Antibiotic residues in milk and dairy products: A review. Food Chemistry, 150, 154–160. https://doi.org/10.1016/j.foodchem.2013.12.035

Ghidini, S., Zanardi, E., Varisco, G., Chizzolini, R., & Ianieri, A. (2003). Validation of a high-performance liquid chromatography method for the determination of antibiotic residues in milk. Food Control, 14(6), 421–427. https://doi.org/10.1016/S0956-7135(03)00016-7

Kaya, S. E., & Filazi, A. (2010). Determination of antibiotic residues in milk samples. Journal of Food and Drug Analysis, 18(2), 142–146.

European Commission. (2010). Commission Regulation (EU) No 37/2010 on pharmacologically active substances and their classification regarding maximum residue limits in foodstuffs of animal origin. Official Journal of the European Union, L15, 1–72.

Codex Alimentarius Commission. (2018). Maximum residue limits (MRLs) for veterinary drugs in foods. FAO/WHO, Rome.

Kaufmann, A. (2012). Analytical strategies for residue analysis of veterinary drugs in food. Journal of Chromatography A, 1217(3), 402–412. https://doi.org/10.1016/j.chroma.2011.06.060

Turnipseed, S. B., Andersen, W. C., & Karbiwnyk, C. M. (2014). Multiresidue confirmation of veterinary drugs in milk using HPLC and LC–MS/MS. Journal of Agricultural and Food Chemistry, 62(47), 11793–11802. https://doi.org/10.1021/jf503553c

Stolker, A. A. M., & Brinkman, U. A. T. (2005). Analytical strategies for residue analysis of veterinary drugs and growth-promoting agents in food-producing animals. Journal of Chromatography A, 1067(1–2), 15–53. https://doi.org/10.1016/j.chroma.2004.10.020

World Health Organization. (2017). Evaluation of certain veterinary drug residues in food. WHO Press, Geneva.

Mitchell, J. M., Griffiths, M. W., McEwen, S. A., McNab, W. B., & Yee, A. J. (1998). Antimicrobial drug residues in milk and meat: Causes, concerns, prevalence, regulations, tests, and test performance. Journal of Food Protection, 61(6), 742–756. https://doi.org/10.4315/0362-028X-61.6.742

Granelli, K., & Branzell, C. (2007). Rapid screening and confirmation of antibiotic residues in milk using HPLC. Analytica Chimica Acta, 586(1–2), 289–295. https://doi.org/10.1016/j.aca.2007.01.038

Roca, M., Castillo, M., Martí, P., Althaus, R. L., & Molina, M. P. (2011). Effect of heat treatments on stability of beta-lactam antibiotics in milk. Journal of Dairy Science, 94(3), 1155–1164. https://doi.org/10.3168/jds.2010-3780