Immunomagnetic separation of Escherichia coli O26, O111 and O157 from vegetables

Aims: Raw fruits and vegetables have been increasingly associated with huma n infections caused by Shiga toxin-producing Escherichia coli. This study e valuates the isolation and detection of E. coli O26, O111 and O157 from veg etable samples using immunomagnetic particles. Methods and Results: Standard cultivation and immunomagnetic separation (IM S) procedures were compared. It was found that immunomagnetic particles cou ld efficiently concentrate E. coli cells, detecting significantly more bact eria than with standard cultivation procedures. Conclusions: Bacteria were detected in 93-100% of the inoculated samples us ing the IMS procedure, but only 36-93% samples tested by standard cultivati on procedures were found to be positive. Significance and Impact of the Study: The results indicate that E. coli O26 , O111 and O157 immunomagnetic particles can be a very useful and efficient tool for the detection of E. coli strains in raw vegetables, and could pro bably be used with samples of animal origin.