Use of Immunomagnetic Separation to Detect and Isolate Shiga Toxin-producing Escherichia coli O157 and the Big Six Non-O157

An article by Calle et.al was published in Food Protection Trends (vol 38, p178-185) assessed the effects of Immunomagnetic separation (IMS) beads in the detection of STEC O157 and non-O157. Most serogroups (O157, O103, O26, O145, O45, and O121) required 3.0 log CFU/ml for accurate detection. However, E. coli O111, IMS required at least 5.0 log CFU/ml of the microorganism to be present in the sample. The data suggest that anti-O111 beads do not capture the target cells as efficiently as the other O groups. Ground beef samples inoculated STEC O157 showed a detection limit of 2.0 log CFU/ ml. Their research also showed that reducing the IMS bead volume by 50% did not impact the recovery. @ http://www.foodprotection.org/files/food-protection-trends/may-jun-18-calle.pdf