In-house validation of PremiTest, a microbiological screening test with solvent extraction, for the detection of antimicrobial residues in poultry muscles.

PremiTest, a microbial inhibition test for the screening of antimicrobial residues, was validated according to the criteria established by Decision 2002/657/EC. Sensitivity, detection capability (CCß), specificity, selectivity, robustness and applicability were evaluated. The methodology involves the technique of solvent extraction, which increases the detection capability of the test for a wider range of antibiotics. The following CCß values in poultry muscle were found: penicillin G ≤ 12.5 µg kg(-1), total sulfonamides ≤ 75 µg kg(-1), erythromycin 75 µg kg(-1) and lincomycin 50 µg kg(-1). The detection capability of chlortetracycline was equal to its maximum residue limit (100 µg kg(-1)) and the method did not detect gentamicin (1000 µg kg(-1)), for which no MRL is established in poultry muscle. Specificity evaluated in relation to different analytes and matrices did not detect any interferences in the tests results; whilst the robustness showed that the pH neutralisation point of the extract affects the analytical results and the kits' performance. Only the screening of tetracyclines requires the analysis of extracts without pH neutralisation. The results of the validation process showed that this method is acceptable for screening ß-lactam, sulfonamide and macrolide antimicrobial groups in the National Residues and Contaminants Control Programme (PNCRC), and that for this it is fit for purpose.

Occurrence of antimicrobial residues in Brazilian food animals in 2008 and 2009.

Brazil is one of the most important countries as a producer and exporter of cattle and poultry. In 2009 cattle accounted for 30% of the export market and 41.4% for poultry meat. The Brazilian National Residues and Contaminants Control Plan (PNCRC) follows the guidelines set by the Codex Alimentarius Commission and checks compliance maximum residue limits (MRLs) to ensure the quality of these commodities. Kidney samples (n = 2978) were analysed between January 2008 and December 2009. Fifteen antibiotics of the macrolide and aminoglycoside groups (clindamycin, eritromycin, lincomycin, tylmicosin, tylosin, amikacin, apramycin, dihydrostreptomycin, gentamycin, higromycin, kanamycin, neomycin, spectinomycin, streptomycin, tobramycin) were determined by a microbiological screening method (FAST) and confirmed/quantified using liquid chromatography (LC-MS/MS and UPLC-MS/MS). In 2008, 1459 samples were analysed by a screening test and liquid chromatography with only one sample (0.07%) exceeded Brazilian legislation limits (>MRL). In 2009, 1519 samples were analysed and none exceeding Brazilian legislation limits (>MRL). The slaughterhouses of 16 states were monitored during the year of 2008, and 18 states were monitored in 2009, being the major producing states most sampled by the PNCRC.

Semileaky waves in dielectric chirowaveguides.

The occurrence of semileaky waves in dielectric chirowaveguides is investigated. It is shown that a thinfilm dielectric chiroslabguide with an achiral superstrate and in which both the film and substrate are chiral can support semileaky modes radiating energy into the substrate, provided that the chirality parameters are properly chosen.