Total Bacterial Count in Soft-Frozen Dairy Products by Impedance Biosensor System

In order to guarantee product safety in the dairy industry, the microbial concentration of food must be ultimately evaluated by means of the standard plate count (SPC) technique, reliable but also slow and difficult to implement in automatic form. On the other hand, detection of bacterial concentration by means of classic impedance microbiology is very attractive due to faster response time (4-14 h versus 24-72 h for the SPC) and easy implementation in industrial machines. Recently, an impedance technique for the detection of bacterial concentration has been introduced that avoids diluting media, thus resulting much simpler to implement in automatic form than existing alternatives. In this paper, various soft-frozen dairy products of different composition and producers have been tested to study the correlation between conventional SPC and such a new impedance technique. It is shown that this later is suitable for real industrial applications.