BIODAM: Biosensor development for the rapid detection of antibiotics in milk

• Forschungsstelle: EU FRP
• Projektnummer: 96.0206-1
• Projekttitel Englisch: BIODAM: Biosensor development for the rapid detection of antibiotics in milk

Schlüsselwörter (Englisch)

Antibiotics residues; milk; immunoassay; evanescent wave sensin

Alternative Projektnummern (Englisch)

EU project number: FAIR3-CT96-2059

Forschungsprogramme (Englisch)

EU-programme: 4. Frame Research Programme - 4.3 Biomedical/Health research

Kurzbeschreibung (Englisch)

See abstract

Partner und Internationale Organisationen (Englisch)

Rhône-diagnostics technologies (F), Central Science Laboratory (UK), IMAG-DLO (NL), RIKILT-DLO (NL), ATO-DLO (NL), Dairygold (IRL)

Abstract (Englisch)

Antibiotics are used for the prevention and the treatment of cows having bacterial infections of the udder (mastitis). Residues of antibiotics will occur in the milk from the treated cows so the procedures for using antibiotics should be strictly observed to prevent contaminated milk reaching the consumer. Milk is examined for antibiotics residues because they pose a hazard to consumers, possibly causing allergic reactions and the development of bacterial resistance. It also has an inhibitory effect on starter cultures of bacteria used to make fermented milk products, which causes financial losses in the dairy industry. The main objective of the project is to develop an improved method to detect antibiotics in milk.
A prototype of sensor system for the detection of antibiotics was designed, fabricated and tested. It comprises a laser at 635 nm wavelength, a moving mirror attached to a flexible mechanical structure, which changes the angle of incidence of the laser beam without changing the incident position on the waveguide. Fluorescent light is detected with a PIN silicon photodiode and a lock-in amplifier and the signal is recorded as a function of mirror position (incidence angle). Software controls the instrument and displays the results.
Photobonding with Optodex was used for the immobilisation of molecules on the sensor surface. Optodex reduces non-specific binding and allows the parallel deposition of different molecules on the same sensor. Several assay were developed for the instrument. An inhibition assay scheme was implemented. The chip is separated in two regions; one for doing a reference immunoreaction (mouse IgG and Cy5-antimouse-IgG), the second one for the antibiotic-specific immunoreaction, and the comparison between the responses on the two regions determines the contamination level. Each antibody developed by the project partners was tested and one (antibody against sulphadimethoxine) was considered for validation in real measurement. Commercially available sulfadimethoxine was bought at a veterinary office and it was injected into the necks of several cows at the experimental farm of IMAG. The milk was collected for up to 8 milkings after the injection and the milk samples were measured with the biosensor system. After 5 milkings the contamination level is under the maximum residue limit. Cross-checked measurements made by RIKILT give a correlation coefficient of 0.97 (comparison with other immunoassay based analysis).
The biosensor was demonstrated for antibiotics measurement in raw milk with a sensitivity compatible with the current European rules. New applications like antibiotics in other matrices or other drug or pesticides will now be investigated.

Datenbankreferenzen (Englisch)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 96.0206-1