Rapid Detection ofBifidobacterium bifidumin Feces Sample by Highly Sensitive Quartz Crystal Microbalance Immunosensor

In this work, a quartz crystal microbalance (QCM) sensor has been fabricated using immunoassay for sensitive determination ofBifidobacterium bifidum. Au nanoparticle has been used for amplifying sandwich assays. The proposed immunosensor exhibited a linear detection range between 10(3)and 10(5)CFU/mL with a limit of detection of 2.1 x 10(2)CFU/mL. The proposed immunosensor exhibited good selectivity forB. bifidumsensing with low cross reactivity for other foodborne pathogens such asLactobacillus acidophilus, Listeria monocytogenes, andEscherichia coli. In addition, the proposed immunosensor has been successfully used forB. bifidumdetection in feces samples and food samples. The frequency decreases of 12, 17, and 10 Hz were observed from the milk samples consisting of the mixtures ofL. acidophilus, L. monocytogenes, andE. coli. The frequency decreases of 8, 15, and 7 Hz were observed from the feces samples consisting of the mixtures ofL. acidophilus, L. monocytogenes, andE. coli.