Smart phone based immunosensor coupled with nanoflower signal amplification for rapid detection of Salmonella Enteritidis in milk, cheese and water

Abstract Salmonella is a standout amongst the most foodborne pathogens causing harmful disease. To protect consumers from food poisoning due to Salmonella infection, it is important to develop a quick, simple, reliable and sensitive method, which can detect Salmonella in foods at low concentration in a timely manner. We have effectively established a novel magnetic nano biosensor with high sensitivity for the visual and quantitative detection of S. Enteritidis from milk, cheese and water. Milk, cheese and water samples inoculated with different concentrations of S. Enteritidis have been tested using anti S. Enteritidis streptavidin magnetic beads and biotin labeled antibody as capture platform and coupled with nanocomposite (detecting antibody-HRP enzyme and inorganic nanoflower), where the signal amplification based on HRP enzyme which is enhanced by the action of nanoflower and produce visual color easily detected by the smartphone device at a very low concentration. The developed assay was able to detect S. Enteritidis in tap water, milk and cheese, with a detection limit of 1.0 CFU mL−1 and 1.0 CFU/g, respectively. Recoveries percentages of spiked milk, cheese and tap water samples with102, 103 and 104 CFU mL−1 from live Salmonella were 98.2, 96.1 and 95.4 (in milk), 94.3, 98.6 and 99.5 (in cheese) and 95.8, 101.2 and 97.8 (in water) using designed device, respectively. The effective application of this innovation in milk and cheese indicates the possibility of its application in various food products.