Water activity of multicomponent food mixture was analysed and measured. Samples of dry fermented sausages with two different starter cultures (Pediococcus pentosaceus + Staphylococcus carnosus and Staphylococcus carnosus + Staphylococcus xylosus + Lactobacillus farciminis) were tested during ripening (21 days) and storing (91 days). The basic raw materials were the same for all samples: lean beef meat, lean pork and pork fat in equal parts, nitrite salt mixture (2.5 %), and sugars (1.0 %). The method used for water activity tests was indirect manometric in a static environment. Moisture content of samples was measured using halogen dryer. The course of water activity and moisture content of sausages was variable during ripening and steady during storage. Diagrams showed gradual decrease of both parameters. Mathematical models of water activity and moisture content for storage of dry fermented sausages were developed and statistically verified. The influence of starter cultures was not significant.

The objective of this study was to determine the changes in water activity and moisture content in the dry fermented sausages Herkules, a typical multicomponent food, during ripening and storage. The sausages were made with lean beef, lean pork, pork fat, nitrite salt mixture, and sugars, and fermented with two starter cultures (Pediococcus pentosaceus + Staphylococcus carnosus and S. carnosus + S. xylosus + Lactobacillus farciminis). The samples were taken and tested during ripening (21 days) and storage (91 days). The water activity was measured by indirect manometric method in a static environment, the moisture content by halogen dryer. The water activity and moisture content decreased considerably, but very irregularily during the ripening, whereas they declined only slowly and linearly during the storage. The decrease during the storage was expressed by mathematical equations describing the changes of water activity and moisture content in function of the time. The use of different starter cultures had no influence on the two variables studied.