A rapid and selective method for monitoring the growth of coliforms in milk using the combination of amperometric sensor and reducing of methylene blue

Yuan Geuy Lee, Hung Yi Wu, Chuan Liang Hsu*, Hong Jen Liang, Chiun-Jye Yuan, Hung Der Jang

*Corresponding author for this work

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

A novel method for monitoring the growth of coliforms in milk was developed based on measuring the current change in an amperometric sensor. The sensor consists of a circuit with a homemade potentiostat and a pair of electrodes. The electrode was immersed in milk samples containing methylene blue with various concentrations of bacterial inoculums. The microbial metabolism led to the reduction of methylene blue resulting in a change of current. The time required to identify readily detectable change (detection time, DT) provided an approximate measurement of the amount of microorganisms in the initial inoculums. The sensor system used in this study has the selectivity towards coliform bacteria such as Escherichia coli and Enterobacter aerogenes. The calibration curve of DT against concentration of coliform showed a linear correlation coefficient (R2 = 0.9192) over the range of 102-108 CFU/mL. The sensor was able to detect the coliform bacteria at initial concentrations of 105 CFU/mL within 6 h, making it suitable for use in real-time monitoring of bacterial growth. This system has potential application in the detection of coliform concentration in milk at dairy farms when a proper selective media is designed.

Original languageEnglish
Pages (from-to)575-580
Number of pages6
JournalSensors and Actuators, B: Chemical
Volume141
Issue number2
DOIs
StatePublished - 7 Sep 2009

Keywords

  • Amperometric sensor
  • Coliforms
  • Detection time
  • Methylene blue

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