Immunochemical determination of fluoroquinolone antibiotics in cattle hair: A strategy to ensure food safety

• Hair analysis is a non-invasive alternative to control misuse of drugs in calves.
• Hair offers a wider time window for drug detection due to its low metabolic activity.
• Fluoroquinolones (FQs) can be easily extracted from hair after by using alkaline pH.
• ELISA can detect FQs residues without purification steps with low detection limits.

Enrofloxacin (ERFX) is a synthetic antibiotic of the fluoroquinolone (FQ) family, which is commonly administered in veterinary medicine. ERFX and its metabolite, ciprofloxacin (CPFX), have been reported to accumulate in hair of treated animals. Therefore, hair analysis is an attractive non-invasive alternative to control misuse of such antibiotic and to ensure food safety by preventing such food derived products arrive to the consumer. In this context, an immunochemical analytical protocol has been established to detect ERFX and CPFX residues in cattle hair samples. Unpigmented and pigmented hair were collected from ERFX-treated and non-treated calves, and the aqueous NH4OH extracts were directly analyzed by ELISA, being possible to achieve limits of detection in the range of 10–30 μg kg−1. A good concordance between HPLC and ELISA measurements was observed. The results demonstrate the potential of the immunochemical procedure reported here to rapidly screen and quantitate FQ residues in hair samples.

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