ABSTRACT
The study was concerned with ambient air and heat-transfer medium levels of benzo(a)-pyrene (BP) and N-nitrosoamines (NA) measured at the input and output of the drying chamber of two milk dryers using different systems of heat generation. Said concentrations were ascertained in the dried product (casein), too. One installation used electricity-heated ambient air, while the other--air-diluted products of natural gas combustion. No significant difference was registered for both dryers between ambient-air and heat-transfer medium concentrations of BP and two NAs detected--NDMA and NDEA. There was no significant difference between BP levels in the casein produced on those installations, the raw material coming from the same lot. The study registered reverse changes in NDMA and NDEA concentrations, with ambient air being heated in the heat generator and heat-transfer agent cooled in the drying chamber.
