An inter-laboratory validation of a multiplex dipstick assay for four classes of antibiotics in honey

In this paper, we report the inter-laboratory validation (ILV) of a recently developed indirect competitive multiplex dipstick (Bee4sensor®) which is capable of the simultaneous detection of residues of some of the most frequently detected antibiotic residues in honey: sulfonamides, tylosin, fluoroquinolones and chloramphenicol. The multi-sensor dipstick can be interpreted via visual observation or by an instrumental measurement of four test lines. Statistical analysis of the ILV data demonstrated that the multi-sensor can reliably detect the presence of sulfathiazole at 25 μg kg(-1) and tylosin at 10 μg kg(-1), which fully meet the 'recommended concentrations' of the EU. Ciprofloxacin and chloramphenicol can be detected at 25 and 5 μg kg(-1) in honey, respectively. Whilst the concentration for chloramphenicol is above the EU minimum required performance limit of 0.3 μg kg(-1), this part of the multiplex test may still be of use to both the industry and enforcement authorities, to provide an early warning of contaminated honey. The estimated false-negative and false-positive rates for this easy-to-use and robust assay were less than 5%.