Stability of cefacetrile in milk samples with various fat content

The consumers should have access to food that is safe and free of contaminants. Unfortunately, the wide use of antibiotics in livestock, not only for medicinal purposes but also as illegal feed additives, may be the reason for emergence of the antibiotic residues in foodstuffs of animal origin. Milk is one of the most essential nutrients for humans during their lifetimes. Failure of the withdrawal periods, or what is highly prohibited but in spite of this increasingly practiced, addition of the antibiotics to milk in order to prolong its freshness, may lead to occurrence of their residues. Cefacetrile is a first generation cephalosporin that is commonly use for the treatment of bovine mastitis. The aim of this work was to determine the stability of cefacetrile in milk samples of different fat content, that is, 0 , 2 , 3.2 % UHT, 2 % pasteurized and ~3.9 % raw cattle milk, for 5 days. Two chromatographic methods were applied and compared for this purpose, that is, thin-layer chromatography and high-performance liquid chromatography. According to the results coming from HPLC-UV analysis, the stability of cefacetrile increase with the increase in the fat mass content in UHT milk. The cefacetrile level in pasteurized and raw cattle milk is similar to that in 3.2 % UHT milk. For the TLC method, this relation can be observed only in the second day of the analysis. The spiked milk samples analyzed by HPLC were deproteinized with MeCN and stored for 5 days of the experiment. Whereas, in the TLC-UV method, the spiked milk samples prepared in the first day of experiment were analyzed directly, without deproteinization. The lower stability of cefacetrile in milk samples observed from the TLC analysis can be related to its partial enzymatic decomposition.