Measurement of ampicillin residue levels in chicken eggs during and after medicated feed administration by LC-MS/MS

Abstract

A simple and sensitive LC-MS/MS method was developed and validated for the determination of ampicillin (ABPC) in chicken eggs. Residues were extracted by reverse-phase solid-phase extraction. Chromatographic separation was performed using a reverse-phase column with an elution gradient. The limits of detection and quantification were 0.01 and 0.1 ng g(-1), respectively. For the 0.1-50 ng g(-1) concentration range, mean recovery and accuracy values were 93.9-98.5% and 100.2-118.0%, respectively. ABPC residue concentrations in eggs before, during and after 7 days of medicated feeding of maximum dosage (40 mg kg(-1) body weight day(-1)) of ABPC were determined with the LC-MS/MS method. The maximum concentration of ABPC in eggs was 3.6 ± 1.7 ng g(-1) (mean ± SD) on the last day of the administration period. Residue concentrations of ABPC in eggs during and after ABPC administration were not over the Japanese maximum residue limit of 0.01 mg kg(-1).

Prevalence and antimicrobial resistance of <i>Campylobacter</i> and <i>Salmonella</i> in layer flocks in Honshu, Japan

“…The use of antimicrobials is not allowed during the laying period in Japan due to residual contamination in eggs. However, ampicillin is excluded from this ban because the concentration of ampicillin residue in chicken eggs during and after administration does not exceed the maximum allowed (0.01 mg/kg) [ 10 ]. Therefore, ampicillin can be used in layers more easily and safely than other antimicrobials, which in turn may favor the selection of ampicillin-resistant C. jejuni in layer farms [ 33 ].…”

<i>Campylobacter</i> spp. prevalence and fluoroquinolone resistance in chicken layer farms

“…Although the maximum residue level (MRL) of ampicillin in chicken eggs is set at 0.01 mg/kg in Japan, residue concentrations of ampicillin in chicken eggs during and after administration do not exceed the MRL, and no withdrawal period has been established [7]. Therefore, ampicillin can be used more easily and safely in grower and layer flocks than other antimicrobial agents, including fluoroquinolones, tetracyclines, and aminoglycosides.…”