title: Rapid enumeration of Staphylococcus aureus in foods by direct demonstration of enterotoxigenic colonies on membrane filters by enzyme immunoassay.
abstract: Based on enzyme-linked immunosorbent assay, a convenient method has been devised for the direct demonstration of enterotoxin B production by Staphylococcus aureus colonies grown for 24 h on membrane filters. The problem of false-positive reactions due to binding of immunoglobulin G to protein A was turned to advantage by conjugating horseradish peroxidase directly to protein A, which then mediated the labeling of the antitoxin. The test requires 3 h to complete and yields a purple stain at the site of enterotoxin B-producing colonies, thus allowing direct enumeration of confirmed S. aureus in foods within 27 h. The method should be applicable to other enterotoxins of S. aureus.
mesh_terms: D001665:Binding Sites; D004768:Enterotoxins / Q000032:analysis* / Q000096:biosynthesis / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005516:Food Microbiology; D007074:Immunoglobulin G / Q000378:metabolism; D008722:Methods; D013205:Staphylococcal Protein A / Q000378:metabolism; D013211:Staphylococcus aureus / Q000378:metabolism
chemical_list: D004768:Enterotoxins; D007074:Immunoglobulin G; D013205:Staphylococcal Protein A; C031818:enterotoxin B, staphylococcal