Detection of <Emphasis Type="Italic">Salmonella typhi</Emphasis> using four developed kits of ELISA for cleaning in place purification

Lack of reliable knowledge to detect antigen of Salmonella typhi in water samples was our reason to modify ELISA method by alteration ratio of buffer-carbonated solution as new kits. Our study was assigned as six groups based on the different concentrations of S. typhi, 10⁴, 10⁶ and 10⁸ cells mL^?1 of S. typhi, one negative control, two positive controls and different buffer-carbonated solutions at dilution of 1:1000, 1:2000, 1:4000 and 1:8000 as our kits. The ODs of S. typhi were measured with the kits and compared to each other. GLM multivariate statistical analysis also was used for selecting more appropriate ELISA kit to measure more precise ODs of the bacteria concentrations. The closest calculated value to the OD value of 4 (positive control) was dedicated to kit 4 measured for positive control 1 (3.49 ± 0.00), positive control 2 (3.75 ± 0.00) and relatively similar (p > 0.05) to that of positive control 2 (3.27 ± 0.00) measured with kit 1. On the other hand, our results showed that great coefficient variations were measured with kit 1 as well as kits 2 and 3 for all groups except for negative controls. It is concluded that buffer-carbonated solution at dilution of 1:8000, as kit 4 is more capable of detecting S. typhi in water samples using ELISA method.