Microbiological method using Bacillus megaterium with fusidic acid for detection of macrolides in milk

[EN] The microbiological method to attain a sensitive detection of macrolides using Bacillus megaterium in agar medium with fusidic acid was designed. To this aim, Mueller-Hinton medium fortified with glucose at pH 8.0, a combination of redox indicators (brilliant black and toluidine blue) and different concentrations of fusidic acid were tested. The addition of fusidic acid in the culture medium improves the sensitivity of this bacteria test and decreases the detection limits of bioassay. The addition of 200 μg/l of fusidic acid detects 35 μg/l of erythromycin, 58 μg/l of tylosin, and 57 μg/l of tilmicosin in milk. This microbiological bioassay could be used as an alternative method of commercial screening test for detecting macrolides in milk, in order to maintain food safety. Partly supported by the Universidad Nacional del Litoral, Santa Fe, Argentina, CAI+D-11 Projects PI 501 201101 00575 LI, H.C.D. Resol 205/13, and Agencia Nacional de Promocion Cientifica y Tecnologica, PICT 2011-368 Res. No. 140/12. Tumini, M.; Nagel, OG.; Molina Pons, MP.; Althaus, RL. (2016). Microbiological method using Bacillus megaterium with fusidic acid for detection of macrolides in milk. Czech Journal of Food Sciences. 34(1):9-15. https://doi.org/10.17221/307/2015-CJFS