Evaluation of Tetracycline Antibiotic Level in Raw Milk using Infrared Fourier Transform Spectrum

Due to the consumption of milk in the daily diet of humans as one of the main food groups, the health of this product is of particular importance. In this study, FTNIR and FTMID were used to evaluate the amount of tetracycline in raw milk and compared with the reference HPLC method. Forty milk samples were prepared with different concentrations of tetracycline 0, 50, 100 and 150 ppb. Also, by comparing the control sample with the samples containing tetracycline, the most changes in the near-infrared spectrum occur in the wavelength range of 5200 to 5000 and 7000 to 6800 and the changes of the middle infrared spectrum occur in the wavelength range of 700 to 600, 1700 to 1500 and 3400 to 3200 cm-1. Using these predictions, the amount of tetracycline was predicted by NIR and MIR methods with correlation coefficients of 0.99 and 0.90 and RMSEP error rates of 18.60 and 20.06, respectively. Although the correlation coefficient of both methods is high, but the error rate of the prediction method is high for both methods, especially the MIR method. But the results of the NIR spectrum are closer to the reference method (HPLC) and can replace this method. Due to the lower error rate of NIR and the advantages of this identification method compared to High Performance Liquid Chromatography, this method can be introduced as a suitable alternative to destructive methods of measuring tetracycline in milk.