Non-Specific Reactions during Immunomagnetic Separation of Listeria

Jarmila Vytřasová¹*, Iveta Zachová¹, Libor Červenka², Jana Štĕpánková² and Marcela Pejchalová<sup>1

1</sup>Department of Biological and Biochemical Sciences, Faculty of Chemical Technology, University of Pardubice, Štrossova 239, CZ-530 03 Pardubice, Czech Republic
²Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, nám. Čs. legií 565, CZ-532 10 Pardubice, Czech Republic

Article history:
Received August 25, 2004
Accepted April 18, 2005

Key words:
immunomagnetic separation, immunomagnetic particles, non-specific reactions, Listeria

Summary:
Problems occurring during the immunomagnetic separation (IMS) of Listeria using immunomagnetic particles Dynabeads^® anti-Listeria (Dynal Biotech, Norway) were specified. Characteristics of these particles were compared with anti-Listeria spp. magnetite particles (Quantum Magnetics, USA). Pure cultures of Listeria innocua, Arthrobacter spp., Bacillus subtilis, Citrobacter braakii, Escherichia coli, Enterobacter aerogenes, Enterobacter cloacae and Staphylococcus aureus were used to evaluate non-specific reactions during IMS. Gram-positive microorganisms, especially Staphylococcus aureus and Arthrobacter spp., were found to be responsible for non-specific reactions in most cases. The capacity of Dynabeads^® anti-Listeria particles was determined to be about 10 % of the initial pure cultures of Listeria spp., after 10 min of incubation. Non-specific reactions during IMS of Listeria were examined on the artificially inoculated food samples in which Gram-positive bacteria showed the highest percentage of capture. Influence of washing in two buffers was also studied.

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