Detection of mastitic milk using a gas-sensor array system (electronic nose)

Milk from mastitic and healthy reference quarters of dairy cows with acute clinical mastitis, and milk from healthy cows, were analysed using a gas-sensor array system (electronic nose) in two experiments using different incubation temperatures. Volatile components in the milk were also analysed by dynamic headspace gas chromatography-mass spectrometry (GC-MS). The results indicated that mastitic milk from cows with acute clinical mastitis could be separated from healthy milk using gas metal oxide semiconductive field effect transistors sensor array technology in combination with a CO2 sensor. The discrimination between samples was better when incubating the samples at 60 °C than when incubating at 40 °C. The GC-MS identified the volatile substances in mastitic milk mainly as sulphides, ketones, amines and acids, while both milk from healthy reference quarters in mastitic cows and milk from healthy cows was characterised by products of lipid oxidation.