Free fatty acid levels in New Zealand raw milk

Raw milk samples (590) were collected from farm vats and analysed for free fatty acids (FFAs) using the Bureau of Dairy Industries method to obtain pr eliminary data about typical FFA levels in New Zealand raw milk. Milk suppl ies from three geographically separate regions were sampled in the autumn, whereas milk supplies from a fourth region were sampled in the autumn and a gain in the following spring, Supplementary samples were also collected fro m this fourth region in the following autumn. FFA levels were typically in the range 0.3-1.1 mmol/100 g fat with a small proportion (<1%) of samples e xceeding 1.5 mmol/100 g fat (flavour threshold). The FFA levels of spring m ilk were significantly lower than those of the autumn milk. Analysis of all the results in terms of the farm dairy equipment showed that elevated milk transport lines, but not milk vat filling position (top filling versus bot tom filling), were significantly correlated with increased FFA levels. Howe ver, the single most important factor appeared to be related to milking mac hine design, with the lowest FFA-containing milk being produced using machi nes in which the milk and air were transported separately.