The production of a functional beverage, supplemented with fruit flavourings meets the problem of microbiological contamination. The most frequent source of such spoilage is the bacteria from the relatively newly discovered genus Asaia. It causes changes in organoleptic properties, creating turbidity, haziness and distinctive sour odour as well as biofilm on production lines which are responsible for secondary contamination of products. For this reason, new methods using natural preservatives are being developed to minimize this microbiological contamination. The application of some plant extracts as an additives in functional beverages production is presumed to have a beneficial effect on reducing adhesive abilities of the bacteria. The aim of this research was to investigate the effects of mint leaves extract on the Asaia lannensis and Asaia bogorensis adhesive abilities to polystyrene. The bacterial adhesion was analysed by means of plate count method and luminometric tests. Additionally, plant extract was subjected to high performance liquid chromatography (HPLC) analysis, in order to check polyphenols content. Results indicates that 10% (v/v) addition of mint extract significantly reduced Asaia spp. adhesion to polystyrene. Due to the presence of bioactive compounds in the used extract, it can be used as an additive to increase microbiological stability as well as health promoting values of beverages.