Development of electrochemical method to detect bacterial count, Listeria monocytogenes, and somatic cell count in raw milk

作者：Huang Yi Ming; Hsu Hung Yu; Hsu Chuan Liang^*

来源：Journal of the Taiwan Institute of Chemical Engineers, 2016, 62: 39-44.

DOI：10.1016/j.jtice.2016.01.030

• Bacterial count
• Listeria monocytogenes
• Somatic cell count
• Detection time
• Lactate dehydrogenase
• Mastitis

Bacterial count, Listeria monocytogenes detection and somatic cell count (SCC) are generally recognized as indexes of raw milk quality which could affect the price and the shelf-life of dairy products. This research was aimed at developing an easy, low-cost and rapid quantitative electrochemical detection method for measuring the three indexes simultaneously. Through the electrochemical sensor, bacterial count or L monocytogenes detection was determined by evaluating the electric-current originated from microbial activity. SCC was determined by measuring current signal produced by the expression of lactate dehydrogenase (LDH) activity, a biomarker also for diagnosing mastitis. The research indicated that the appropriate conditions for applying the biosensor to bacterial count detection ranging from 10(2) to 10(8) CFU/ml within detection time (DT) of 1-10 h are 35 degrees C at 1 V and that the optimal conditions for L. monocytogenes detection are 37 degrees C at 1 V, under pH 9.4, associated with a Fraser selective broth. The optimal conditions for SCC detection ranging from 350 to 780 thousand SCC/ml (R-2 = 0.907) within 60 s (DT) are 42 degrees C at 0.5 V, under pH 9.0. The biosensor is shown to be a promising approach for the detections in raw milk.

• 出版日期2016-5