Abstract:Immunochromatography assay (ICA) was established in this study by using fluorescent microspheres (FMs) as the probe to obtain a rapid, sensitive and specific method for the detection of Salmonella typhimurium (ST). Anti- ST immunomagnetic beads (IMB) was prepared by coupling magnetic carboxyl-microspheres with antibodies, and FM-ICA was combined with IMB for enrichment and detection of ST in three food samples. Under optimal conditions, the linear range of FM-ICA was 3.16×106 ~ 2×109 CFU/mL with the recovery of 80% ~ 120%, and the coefficient of variation was less than 5%. The results showed a cross-reaction with Salmonella when the concentration of bacteria was more than 1×108 CFU/mL , and the test results of other 12 non-target bacteria were negative when the concentration was less than 1×108 CFU/mL.. The recoveries of three simulated foods by FM-ICA+IMB were 38%~55%. Thetomato samples had little effect on the recovery while eggs and pork showed significant effectson the recovery. In addition, the sensitivity of the combined method could be 1×105 CFU/mL, which was a 30 times higher than that of FM-ICA method, and the detection process could be completed within 2 hours. The combined method established in this study was of great significance for rapid screening of Salmonella typhimurium.
