The E. coli O104 IMS beads are immunomagnetic separation beads designed for the rapid and selective concentration of Escherichia coli serogroup O104 to help with their confirmation on selective confirmation agars. The E. coli O104 IMS beads should be used as part of the USDA-FSIS test protocol described in the USDA-FSIS Microbiology Laboratory Guidebook (MLG) Chapter 5B “Detection, Isolation and Identification of Top Seven Shiga-Toxin Producing Escherichia coli Strains (STEC) from Meat Products and Carcass and Environmental Sponges”. The IMS beads provided in the kit are coupled to antibodies against E. coli serotype O104. The E. coli O104 IMS beads should be used as part of the USDA-FSIS test protocol described in the USDA-FSIS Microbiology Laboratory Guidebook (MLG) Chapter 5B “Detection, Isolation and Identification of Top Seven Shiga-Toxin Producing Escherichia coli Strains (STEC) from Meat Products and Carcass and Environmental Sponges”. The MLG utilizes sample enrichment in modified tryptic soy broth, followed by multiplexed Real Time-PCR assays targeting stx1, stx2 and eae genes and the wxz gene in the O-antigen gene clusters of the six serogroups, and then immunomagnetic separation (IMS) followed by plating onto Rainbow Agar (mRBA). Colonies are then tested for specific O antigens using latex agglutination and positive colonies are purified on Sheep Blood Agar (SBA) and confirmed using PCR and biochemical identification.