Russian biologists have developed testing systems for quick measuring antibiotic concentration in various milk products. New testing systems, based upon immuno-assay technologies, are highly sensitive and specific.

Antibiotics have become an integral part of modern livestock farming. These chemical substances are used for preventing and treatment of various infectious and parasitic diseases, for growth stimulation and etc, and that is why antibiotics can be found in almost all products of animal origin, including meat ant milk.

When antibiotics enter human organism, they may be the cause of many health disorders, like so-called dysbacteriosis (imbalance of proper microbial fauna of an organism) or allergies. Presence of antibiotics in milk can be a serious problem for production of various cultured dairy products. Antibiotics, when used without a serious reason, can promote formation of drug-resistance in microorganisms. Many countries of the world, including Russia, have special regulations for antibiotic concentration in food products, thus content of these substances in food should be under stiff control.

Institute of Vaccines and Serums suggest measuring antibiotic concentration in milk by means of immuno-assay technology. The technique is based upon an immunological response of a tested substance and an antibody, specific to this substance Moreover, the technique can not only say whether tested substance is present in milk or not, it can also measure its concentration. Scientists synthesized specific antibodies to various antibiotics and developed testing systems for following eight antimicrobial agents: laevomycetin, cortin, bacitracin, enrofloxacin, ciprofloxacin, gentamicin, neomycin, and kanamycin.

 

 

Testing systems, described above, were used for testing 106 samples of milk and cream of both domestic and foreign origin and fat content between 0.1% up to 35%. Tests revealed that fat content had no effect on analysis results, and that is why no specific sample preparation is required for this analysis. Moreover, antibiotic concentration can be measured both in raw (unpasteurized) milk and in boiled milk.

New testing systems appeared to be very useful, because a large number of milk samples has shown positive reaction on antibiotics, and concentration of these chemical substances was often above permissible level.

An antibiotic, most often detected in milk and cream, is called tetracycline, and every fourth sample of milk and cream contained impermissible concentration of this antibiotic. Some samples contained a combination of various antibiotic agents, and researchers worry that in this case their cumulative effect would be negative, even if concentrations of separate antibiotics do stay within permissible limits.

Russian scientists believe that they have created a convenient technique for testing quality of milk products. Immuno-assay technologies proved to be effective, sensitive and able to detect individual antibiotic agents in the presence or absence of other antimicrobial products.

Source:
      Science News

Kizilova Anna