In order to ensure the safety of infant formula powder in China,a rapid and sensitive detection method for food-borne bacteria is urgently needed.We have developed a reliable immunoassay based on nuclear magnetic resonance for the specific detection of Enterobacter sakazakii in dairy samples with biofunctionalized magnetic nanoparticles.This method is able to detect Cronobacter sakazakii in milk powder and cheese samples at 1.1 to 11 MPN using the most-probable-number (MPN) assay,within an incubation period of less than 2 h.Longer incubation time (>4 h) or higher pH (>7) will decrease the sensitivity of this method.This method does not fit for the detection of bacteria at higher concentrations (>1100 MPN).This method has great potential to becomea useful tool for the rapid detection of bacterial contaminations in food,environmental and agricultural samples.
Immunoassay Magnetic nanoparticles Cronobacter sakazakii Magnetic relaxation
Yu Zhao Yuting Yao Ming Xiao Yan Chen Charles C.C. Lee Li Zhang Kelvin Xi Zhang Shiping Yang Ming Gu
Department of Life and Environment Science College,Shanghai Normal University,100 Guiling Road,Shang Department of Life and Environment Science College,Shanghai Normal University,100 Guiling Road,Shang School of Environmental and Life Sciences,University of Newcastle,Singapore 169567,Singapore Howard Hughes Medical Institute,Department of Pathology and Laboratory Medicine,David Geffen School Young Drive South,Los Angeles,CA 90095,USA Shanghai Entry-Exit Inspection and Quarantine Bureau of the People’s Republic of China,1208,Mingshen