Scientific journal

49 2010

Journal of Food and Nutrition Research
Summary No. 1 / 2010

Utilization of B. cereus and B. subtilis strains in plate diffusion methods for the detection of tetracycline residues in milk
Journal of Food and Nutrition Research, 49, 2010, No. 1, s. 37-44

Pavlína Navrátilová, University of Veterinary and Pharmaceutical Sciences Brno, Faculty of Veterinary Hygiene and Ecology, Department of Milk Hygiene and Technology, Palackého 1–3, CZ – 612 42 Brno, Czech Republic. E-mail:

Summary: The reference method for the detection of residues of antimicrobial substances in raw materials and foods of animal origin is the plate diffusion method both in the Czech Republic and the European Union (EU). The aim of the study was to verify the suitability of the plate diffusion method with strain B. cereus CCM 869 (= ATCC 11778) that is recom¬mended by EU guidelines (the STAR protocol) for the detection of residues of tetracycline antibiotics (chlortetra¬cycline, tetracycline and oxytetracycline) in milk, and to compare its sensitivity with that of strain B. subtilis CCM 4062 (= BGA) that is recommended for the detection of antibiotics according to the guidelines of the Czech National Reference Laboratory. Chlortetracycline was the only substance reliably detected by the methods tested at levels equal to the maximum residue limit (MRL) of 0.1 mg•kg-1. The sensitivity of the assay with B. cereus for tetracycline and oxytetracycline were six and eight times the MRL, respectively. The sensitivity for tetracycline was higher when using the discs of a diameter of 12.7 mm. The assay with B. cereus facilitated detection of tetracycline at a concentration of 0.5 mg•l-1 and oxytetracycline at a concentration of 0.7 mg•l-1. Neither of the methods reached the required sensitivities for tetracycline and oxytetracycline, respectively.

Keywords: antibiotic; residue; agar diffusion; tetracycline

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