title: Development of a rapid multiplexed assay for the direct screening of antimicrobial residues in raw milk.
abstract: Antimicrobial residues found to be present in milk can have both health and economic impacts. For these reasons, the widespread routine testing of milk is required. Due to delays with sample handling and test scheduling, laboratory-based tests are not always suited for making decisions about raw material intake and product release, especially when samples require shipping to a central testing facility. Therefore, rapid on-site screening tests that can produce results within a matter of minutes are required to facilitate rapid intake and product release processes. Such tests must be simple for use by non-technical staff. There is increasing momentum towards the development and implementation of multiplexing tests that can detect a range of important antimicrobial residues simultaneously. A simple in situ multiplexed planar waveguide device that can simultaneously detect chloramphenicol, streptomycin and desfuroylceftiofur in raw dairy milk, without sample preparation, has been developed. Samples are simply mixed with antibody prior to an aliquot being passed through the detection cartridge for 5 min before reading on a field-deployable portable instrument. Multiplexed calibration curves were produced in both buffer and raw milk. Buffer curves, for chloramphenicol, streptomycin and desfuroylceftiofur, showed linear ranges (inhibitory concentration (IC)20-IC80) of 0.1-0.9, 3-129 and 12-26 ng/ml, whilst linear range in milk was 0.13-0.74, 11-376 and 2-12 ng/ml, respectively, thus meeting European legislated concentration requirements for both chloramphenicol and streptomycin, in milk, without the need for any sample preparation. Desfuroylceftiofur-contaminated samples require only simple sample dilution to bring positive samples within the range of quantification. Assay repeatability and reproducibility were lower than 12 coefficient of variation (%CV), whilst blank raw milk samples (n = 9) showed repeatability ranging between 4.2 and 8.1%CV when measured on all three calibration curves. Graphical Abstract MBio SnapEsi reader and cartridge.
authors.affiliation: Institute for Global Food Security, School of Biological Sciences, Queen's University, David Keir Building, Stranmillis Road, Belfast, BT95AG, UK, terry.mcgrath@qub.ac.uk.
authors.forename: Terry F
authors.initials: TF
authors.lastname: McGrath
authors.forename: Laura
authors.initials: L
authors.lastname: McClintock
authors.forename: John S
authors.initials: JS
authors.lastname: Dunn
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Husar
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lochhead
authors.forename: Ronald W
authors.initials: RW
authors.lastname: Sarver
authors.forename: Frank E
authors.initials: FE
authors.lastname: Klein
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Rice
authors.forename: Katrina
authors.initials: K
authors.lastname: Campbell
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Elliott
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis; D000890:Anti-Infective Agents / Q000032:analysis*; D002417:Cattle; D002511:Cephalosporins / Q000032:analysis*; D002701:Chloramphenicol / Q000032:analysis*; D005504:Food Analysis / Q000191:economics / Q000379:methods; D005506:Food Contamination / Q000032:analysis*; D057230:Limit of Detection; D008892:Milk / Q000737:chemistry*; D015203:Reproducibility of Results; D013307:Streptomycin / Q000032:analysis*; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D002511:Cephalosporins; C063324:desfuroylceftiofur; D002701:Chloramphenicol; D013307:Streptomycin