Fermentation of vegetables and fruits is a traditional preservation technique, e.g. in Eastern Europe. Although usually spontaneous fermentation processes are applied, the addition of lactic acid bacteria (LAB) starter cultures could accelerate processing and improve the consistency and quality of the end-products. The application of Lactobacillus plantarum IMDO 788 as a starter culture strain for cauliflower and mixed vegetable fermentations resulted in accelerated acidification as compared with the spontaneous fermentations. The strain dominated the background microbiota throughout the process, whereas the spontaneous fermentations were characterised by widely variable species diversity. During the spontaneous fermentations, almost all carbohydrates were converted into lactic acid, ethanol, mannitol and acetic acid, indicating the participation of both heterofermentative and homofermentative LAB species. During the starter culture-added fermentations, residual carbohydrates were found and lactic acid and ethanol were the main end-metabolites. Vegetable-associated aromas, ethyl acetate and isoamyl acetate were produced during all fermentations. The high concentration of ethanol and the production of ethyl acetate and isoamyl acetate suggested the involvement of yeasts during all fermentations. Lactobacillus plantarum IMDO 788 was an adequate starter culture strain for vegetable fermentations, prevailing over endogenous LAB communities. Further optimisation of the starter culture formulation is necessary to avoid yeast growth.