Resumen

SANDOVAL T., Luigi. Application of the immunomagnetic separation technique for Escherichia coli O157:H7 isolation in milk samples.. Rev. Soc. Ven. Microbiol. [online]. 2004, vol.24, n.1-2, pp.50-58. ISSN 1315-2556.

The application of Immunomagnetic Separation (IMS) technique, previous to the standard culture in Mac Conkey-Sorbitol (MK-S), was studied to detect E. coli O157:H7 in milk and to determine the influence of samples dilution, incubation time, number of washings and immunobeads volume, over the growth of E. coli O157:H7 on MK-S post-immunoseparation. Incubation time and immunobeads volume were not determinant when applying the technique with UHT and crude milk. It was found differences in the recovery of microorganisms when applying samples dilution factor and number of washings. The previous IMS to the culture on MK-S, is an effective, fast, and easy application technique to detect E. coli O157:H7 in milk. It is recommended to make 4 dilutions and at least 4 washings in crude milk. The IMS accompanied by MK-S seeding allows milk identification of E. coli O157:H7 in 18 hours.

Palabras clave : Immunomagnetic separation; microbiology; rapid tests; Escherichia coli O157:H7.