Probe characterisation, design and evaluation for the real-time quality Indication of milk

[摘要] In order to rapidly detect, monitor and predict changes in milk as it ferments, sensors would need to bedesigned specifically for milk. To this end, invasive surgical stainless steel probes were investigated andthe probe impedances were characterised according to measurements made in various saline concentrations.Based on these findings, specific probes were designed that were robust and easy to use in milk.To measure multiple probe sensors continuously and accurately, an automatic measurement device wasdesigned and manufactured. The device was self-sustaining, portable and calculated and stored all probeimpedance data internally, allowing experimental runs to take place in controlled laboratory environments.The probes designed in this thesis were consequently tested in various milk fermentation experimentsand it was found that surgical stainless steel probes were effective at detecting and monitoring fermentationchanges. The probe impedance changes also lead the pH changes in milk, giving it a predictive element.The probe sensor studies provided enough data so that studies could be done into potential non-invasivesensors. Therefore, capacitive sensors were investigated and a fringe field capacitor was presented as apotential non-invasive milk fermentation sensor.

[发布机构] Stellenbosch University