The CFU assay is labor intensive and time-consuming with some
standardized procedures requiring up to 7 days (de Boer and
Beumer, 1999). Immunological assays require expensive materials
and involve labeling and multiple washing steps (Beumer and
Brinkman, 1989; Palumbo et al., 2003). The nucleic acid probebased
technique is expensive and requires specialized facilities
(Cai et al., 2014). Moreover, nonviable cells and single naked DNA,
extraction and degradation of nucleic acids, and/or the direct inhibition
of the PCR may lead to false positive/negative responses
(Wilson, 1997). Except for the CFU assay, most methods cannot
differentiate live/dead bacteria.