Development of a flow immunoassay system for the detection of salmonella typhimurium

A flow immunoassay system has been developed for the detection of Salmonella typhimurium by immobilization of antibody to Salmonella onto tygon tubing by adsorption and onto polyethylene tubing, by covalent binding. After liquid containing Salmonella cells or Salmonella antigen was allowed to interact with the immobilized, antibody, glucose oxidase labeled antibody to Salmonella was injected to the system. The bound antigen was quantified by electrochemical detection of H₂O₂ produced from the enzymic oxidation of glucose to gluconic acid. In view of the low non-specific binding, sensitivity and reusability, the polyethylene immanoreactor provided a better performance. The system was capable of detecting as low as 10⁵ - 10⁶Salmonella cells/ml in less than 10 minutes. The immunoreactor could be regenerated forat least 50 times during one month of the experiment. The detection limit of the tygon immunoreactor was somewhat higher (10⁶ -10⁹ cells/ml). Even though the anti-Salmonella antibody was easily immobilized on the tygon tubing, the system was not reusable and exhibited a very high non-specific binding.