In the production conditions, in ecologic farms, the effect of the bacterial starter culture supplemented with the mineral and vitamin mix on the stimulation of development of lactic fermentation process and on inhibition of moulds development, including toxigenic ones, during the silaging of meadow grass, had been tested. The starter culture of the bacterial preparation comprised selected strains of the species as follows: Lactobacillus plantarum, Lactobacillus buchneri and Lactobacillus brevis; the mineral and vitamin additive comprised calcium, phosphorus, manganese, magnesium and zinc compounds and beta-carotene (allowed for application in ecologic production). Silages from meadow grass produced with the addition of the bacterial, mineral and vitamin preparation were characterised with higher quality, nutritive value, extended oxygen stability (up to 11 days) and the number of mildew units j.t.k. in 1 g of silage lower by two grades as compared to the silages produced without this preparation. The control (reference) silages were contaminated with moulds focuses which, after isolating and cleaning, were identified - according to their morphologic properties - as a toxigenic species Aspergillus flavus. On the basis of the model experiments in laboratory conditions it was stated that the isolated moulds Aspergillus flavus produced aflatoxin B1 and total aflatoxins.