Detection of staphylococcal enterotoxin B (SEB) with surface plasmon resonance biosensor

An automated and rapid method for detection of staphylococcal enterotoxins is needed by the food industry. We have developed a biosensor Sandwich Assay using a surface plasmon resonance (SPR) biosensor for the detection of Staphylococcus aureus enterotoxin B (SEB). The assay is based on the immobilization of SEB antibody, capturing the SEB from the standard solutions or samples, and followed by the capture of the second SEB antibody by the sensor surface. The assay conditions were optimized to detect SEB in Hepes buffer and in ham extracts. The results indicated that SEB can be detected at 2.5 ng/mL of HBST buffer or in ham tissue extract. The calibration lines in 8 replicate analyses were determined from SEB spiked in ham extract and resulted in a mean R-2 of 0.982 (SD = 0.026) and 0.995 (SD = 0.005) from SEB spiked in the supernatant of the centrifuged ham extract. Analysis of 10 and 20 ppb SEB inoculated on the surface of ham slices resulted in recoveries of 70 and 87%, and 62 and 86%, respectively, but at lower doses of 2.5 and 5 ppb SEB, the recoveries were 53, 0 and 65 and 16%, respectively. The extraction procedure can be improved to increase recoveries and the utilization of a more specific antibody can also improve the detection sensitivity. The Biacore method of analysis is semiautomated and can be developed for multi-toxin detection in foods.