The beneficial effects of high-temperature pre-heating of the milk before spray drying constitute the main features which emerged from previous experimental work (1). The bacteriological advantages became obvious during the experimental period, and high-temperature pre-heating at 190°F. was introduced as standard practice following the experimental runs. Further observations have been made during two complete drying seasons, in ordinary commercial operation wherein the milk was collected once daily without special selection and pre-heated to 190°F. without preliminary clarification. This work has afforded opportunity to discover any possible practical difficulties, and also to examine a much wider range of samples than was possible during the experimental period.