Effect of Heating on the Stability of Quinolones in Milk

Abstract

Nowadays, the possible public health risk associated with the presence of quinolone residues and other antibiotics in milk is well-known, but there is a lack of information about the effect milk processing temperatures have on the presence of antimicrobial residues. The aim of this work was to determine the effect of different temperatures and heating times on the concentration of quinolones in milk by employing liquid chromatographic equipment analysis with fluorescence detection. In order to determine the thermo-stability of these compounds, the first-order kinetic model was applied, and the activation energies, half-lives, and percentages of degradation of each compound were calculated. Results showed that quinolones are very resistant to different heat treatments with maximum losses of concentration of 12.71% for ciprofloxacin and 12.01% for norfloxacin at 120 degrees C and 20 min. The high stability of quinolones represents a significant risk to human health because the residues of these antibiotics can remain in milk after heat treatment and, therefore, can reach the dairy industry and consumers.

Thermodynamic analysis of the thermal stability of sulphonamides in milk using liquid chromatography tandem mass spectrometry detection

“…The activation energy values of SAs in skimmed milk (Table 5) were similar than those calculated by Roca et al (2010) for the thermal degradation of quinolones (between 27.90 kJ/mol for flumequine, and 63.42 kJ/mol for norfloxacin) and beta-lactam antibiotics, with values ranging from 50.30 kJ/mol for cefquinome to 88.84 kJ/mol for cefoperazone (Roca et al, 2011). It should be emphasised that there are no values for the kinetic parameters (Ea and ln A) of SAs in the reviewed literature, even in aqueous solutions.…”

“…The values of the ''k 1 '' parameters obtained (Table 3) were slightly higher than those reported by Roca et al (2010) when studying the thermal stability of quinolones (ciprofloxacin, enrofloxacin, flumequine, norfloxacin and oxolinic acid) in skimmed milk at different temperatures (80, 90 and 100°C). Nevertheless, these coefficients were similar to those calculated by Roca et al (2011) in a study into thermal degradation of penicillins (amoxicillin, ampicillin, cloxacillin and penicillin), but lower than those determined for cephalosporins (cefoperazone, cefquinome, cephalexin, cephalonium, cephapirin and cephuroxime) at the same temperatures.…”

“…In previous studies (Roca, Castillo, Marti, Althaus, & Molina, 2010;Roca, Villegas, Kortabitarte, Althaus, & Molina, 2011), kinetic models of degradation to study quinolones and beta-lactam antibiotics in milk at various temperatures were established employing chromatographic methods. In both works, the results show that the analyzed substances are resistant to the pasteurisation (72°C; 15 s) and Ultra High Temperature sterilisation (140°C; 4 s), except for some cephalosporins which substantially degrade under the effect of these heat treatments.…”

The Bovine ATP-Binding Cassette Transporter ABCG2 Tyr581Ser Single-Nucleotide Polymorphism Increases Milk Secretion of the Fluoroquinolone Danofloxacin

“…Milk residues of fluoroquinolones are particularly relevant, since these antibiotics are drugs with considerable stability when subjected to thermal treatments and cooking procedures. Consequently, they can remain in milk after dairy processing, and can thus reach consumers (Roca et al, 2010) if the withdrawal times are not fulfilled. Likewise, intermittent exposure of consumers of dairy products to low levels of fluoroquinolones can produce hypersensitivity reactions or affect the intestinal microflora via food intake (Normanno et al, 2005).…”

Microbial screening for quinolones residues in cow milk by bio-optical method

“…In order to eliminate the interference of natural flora in raw milk, and considering the thermal stability of quinolones [23], blank and spiked raw milk samples were heated in water bath at 83 • C for 5 min, immediately cooled down and kept at 4 • C until the assay. Blank and spiked pasteurized milk samples were kept at 4 • C until the assay.…”