Spectroscopic Studies of Tetracycline Interaction with Milk

The critical importance of controlling antibiotic residues in milk for human health necessitates advanced monitoring methods, as these residues can induce allergies, contribute to bacterial resistance, and disrupt gut microflora. Milk safety is key to preventing human health risks worldwide. The aim of the work is to identify consistent patterns and search for informative parameters and ranges in spectral diagnostics of tetracycline interaction with milk.

The absorption and luminescence spectra of milk were measured using a CM2203 spectrofluorimeter. Initial milk parameters were assessed with an “Expert Profi” ultrasonic analyzer, and antibiotic content was verified using “BIOEASY 4in1 BSCT” test kits.

Analysis of milk contaminated with tetracycline across the 230-600 nm range revealed four distinct absorption peaks at 290, 324, 360, and 445 nm, with the peak at 445 nm exhibiting twice the intensity of the others. The integral and statistical parameters of the spectra were calculated, leading to the derivation of approximate dependencies of these parameters on antibiotic concentration. This process enabled the proposal of specific informative ranges and parameters for detecting and quantifying tetracycline. While the complex matrix of cow's milk renders the 230–310 nm and 310–340 nm ranges ineffective for analysis due to minimal parameter changes, the constructed dependencies identified two key diagnostic ranges: 340-400 nm and 400-520 nm.

Approximate dependences of the spectrum parameters on the concentration of the antibiotic are obtained. Informative ranges and parameters for diagnosing the presence and tracking the concentration of tetracycline in milk are proposed.

These findings confirm that the 340-400 nm range (associated with nucleotide, protein, and flavonoid absorption) and the 400-520 nm range (associated with riboflavin absorption) are diagnostically informative, with the latter enabling qualitative detection of tetracycline based on parameters H, As, and Ex. The results pave the way for developing rapid, spectral-based methods for dairy product safety monitoring.