Testing of Raw Milk for Tetracycline Residues

Abstract

Navrátilová P., Borkovcová I., Dračková M., Janštová B., Vorlová L. (2009): Occurrence of tet-racycline, chlortetracycline, and oxytetracycline residues in raw cow's milk. Czech J. Food, Sci., 27: 379-385. The objective of this study was the detection of tetracycline, chlortetracycline and oxytetracycline residues in raw cow's milk. When analysing bulk milk (n = 57) and tanker trailer'a (n = 113) samples, two methods were used simultaneously: a specific rapid test Milk Tetrasensor Kit and high performance liquid chromatography (HPLC) with ultraviolet detection and isocratic elution. For HPLC analysis, Breeze (Waters, USA), a liquid chromatographic system, was used. The samples underwent solid phase extraction before the HPLC analysis. The Nova Pack C8 column (3.9 × 150 mm, 4 μm, Waters) and mobile phase (0.8 ml/min) consisting of acetonitrile, methanol, and 0.05 mol/l of oxalic acid in a 13:13:74 ratio were used. None of the samples analysed with the use of the specific rapid test displayed the presence of tetracycline antibiotics. In all of the samples analysed by means of HPLC, low concentrations of tetracycline antibiotics residues were detected. None of the samples displayed the presence of chlortetracycline. All of the analysed samples displayed residues of tetracycline. Oxytetracycline residues were detected only in 50.6% of analysed samples.

Investigations on the amalgamation of gold nanorods by iodine and the detection of tetracycline

“…[28]. Milk was heated for 10 min at 80℃ and centrifuged at 10000 r/min for 25 min to separate protein and grease.…”

“…Besides, their degradation products are also toxic to some degree [17] . Furthermore, because of the complexation of tetracycline with Ca 2+ [18] , relatively high level of antibiotic residues enrich in the animal bones when animals are bred with tetracycline in a long period [19] , as well as in fish [4,20] , meat [21][22][23] , eggs [24][25][26][27] and milk [28,29] . Therefore, the detection of tetracycline is closely linked to human life.…”

Suitability of the charm HVS and a microbiological multiplate system for detection of residues in raw milk at EU maximum residue levels

“…The false-positive results of the Charm HVS test for tetracyclines may be related to the fatty acid content of raw milk samples (2,5). In an earlier study (15), it was shown that tetracycline residue concentrations found with the Charm test at levels below 150 ng/ml should be considered with reservation. Moreover, we clearly demonstrated that UHT and/or Charm reference milk is not suitable for use as the reference blank sample for Charm HVS tests for tetracyclines ( Table 2).…”

Aplicación de métodos microbiológicos en la detección de residuos de antimicrobianos en la leche de oveja.

“…El "Sistema Microbiológico Multiresiduo o Multiplaca" (SMMP) que ha sido descrito por Nouws et al (1998Nouws et al ( , 1999a, consiste en la preparación de 7 placas de Petri (140 mm de diámetro) con 6 microorganismos cuyas características aparecen reflejadas en el Cuadro 15. En este cuadro se muestra con detalle los microorganismos empleados (formas esporuladas y vegetativas), su concentración, la composición y pH de los medios de cultivo, la temperatura y tiempo de incubación, así como los residuos objeto de detección en las distintas placas.…”

“…También, Nouws et al (1998) cuando utilizan Bacillus cereus ATCC 11778 como sensor biológico, observan halos de inhibición mayores para muestras que contienen 10 µg/kg de doxiciclina (32,3 mm) o clortetracilina (29,9 mm), que en muestras enriquecidas con 30 µg/kg de oxitetraciclina (22,2 mm) o tetraciclina (22,6 mm), poniendo de manifiesto la mayor sensibilidad de este microorganismo para detectar residuos de doxiciclina y clortetraciclina en leche que el resto de tetraciclinas.…”