Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6609810 | Electrochimica Acta | 2015 | 7 Pages |
Abstract
Detection of pathogenic bacteria in dairy farms and processing plants is important for milk quality control. In this study, a simple in situ method for determining the bacterial concentration in milk was developed with an interdigitated microelectrode sensor. This method was based on a punctual measurement of the electrode-milk interface impedance change due to bacterial metabolism in the milk. The interface impedance varied predominately at low frequencies, attributed to the change on the double-layer capacitance. The detection time TD, defined as the time required to attain a â10% impedance change at 10Â Hz, became a practicable means for the estimation of initial E. coli concentration in milk samples. Regression analysis resulted in a third-order polynomial relationship between the detection time and the logarithm of the initial E. coli concentration (N0, cells/ml) in a milk sample, i.e., log N0Â =Â 11.48Â -Â 2.33 TDÂ +Â 0.288(TD)2Â -Â 0.0154(TD)3 with R2Â =Â 0.9988. The sensor was able to detect E. coli in milk of initial concentrations as low as 7Â cells/ml. The proposed impedance sensor is suitable for determining bacterial contamination at dairy farms and processing plants.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Chemical Engineering (General)
Authors
Jen-Tsai Liu, Kalpana Settu, Jang-Zern Tsai, Ching-Jung Chen,