In this study, a rapid immuno-chromatographic assay was developed to detect Salmonella Typhimurium. This assay was based on the lateral flow immunoassay. Two different anti-Salmonella polyclonal antibody (Pab) are used in this strip assay for the double antibody sandwich immunoassay method. The strip sensor was composed of sample pad, conjugation pad, membrane, and absorbent pad. For the optimal conjugation between nano-gold and anti-Salmonella Pab, the pH value of colloidal gold solution was determined to 8.4. To prevent non-specific binding between nano gold and anti-Salmonella Pab, sample pad and membrane was treated with PBS buffer, included 2% BSA and 10% sucrose. The control and detection zones were visually detected according to antigen-antibody binding. The detection limit of the developed strip assay was 105 CFU/mL within 10 min, and improved until 104 CFU/mL after 12 hr.

This study was performed to develop and optimize a rapid strip kit for the dual-detection of Aflatoxin B1 (AF) and Ochratoxin A (OTA). The strip kit is composed of sample pad, conjugation pad, nitrocellulose membrane, and absorbent pad. Manually spotted mycotoxin-BSA conjugates and anti-mouse IgG on nitrocellulose membrane were used as the test line and the control line, respectively. Conditions for rapid and easy detection of mycotoxins, conjugation between toxin-MAbs and nano Au particles, pretreatment method of pads, and composition of standards solutions were optimized. Feasibility of the strip kit to detect AF and OTA were evaluated with standard samples. Test results were acquired in 10 min and the detection limits were 100 ppm for AF and OTA, respectively.