A semi-homogeneous amperometric immunosensor for protein A-bearing Staphylococcus aureus in foods.
A semi-homogeneous amperometric immunosensor specific to the protein A of Staphylococcus aureus was developed using direct electrochemical detection of phenol produced by alkaline phosphatase from phenyl phosphate. The immunosensor could reliably detect strains of protein A-bearing S. aureus in pure cultures at ca. 10(4) cfu/ml, and at ca. 10(5) cfu/g or ml in various food samples. Due to its semi-homogeneous nature, the system was very simple, easy to operate, and labour-saving. The good correlation between the amperometric current generated by the immunosensor and plate counts illustrated the potential usefulness of this simple system. It proved to be a reliable 24-h detection method for food samples containing very low numbers of protein A-bearing S. aureus after pre-enrichment, as it was able to detect cells that could not directly be enumerated by plate counts.
Department of Microbiology, AFRC Institute of Food Research, Reading Laboratory, Berkshire, UK.
B
B
Mirhabibollahi
J L
JL
Brooks
R G
RG
Kroll
D015374:Biosensing Techniques; D015169:Colony Count, Microbial; D004563:Electrochemistry; D005504:Food Analysis / Q000379:methods; D005516:Food Microbiology; D013205:Staphylococcal Protein A / Q000032:analysis*; D013211:Staphylococcus aureus / Q000032:analysis*
D013205:Staphylococcal Protein A