Electronic tongue for fresh milk assessment A revisit of using pH as indicator

This paper reports an investigation about using pH as an indicator of milk freshness. The objective is to develop a means to distinguish between fresh milk and spoilt milk. An electronic tongue (e-tongue) with a pH sensor has been implemented together with a graphic user interface. The definition of fresh milk was established and the e-tongue was used to measure both pasturised and non-pasturised milk in different conditions (fresh/spoilt). Based on the experimental results, we conclude that the pH parameter is not suitable as a sole indicator of milk freshness. Additional measurement using e.g. carbon dioxide sensor is required.