Microorganisms are often located within surface-associated multicellular aggregates known as biofilms. The human gastrointestinal tract (GI-tract) carries a microbiota that is constantly affected by extraneous influences, and hence upholding and improving the microbial balance has increased the request for probiotics. Several Lactobacillus reuteri strains have probiotic properties and are used in food technology. In this study the growth characteristics of L. reuteri was investigated using the morphology and stability of L. reuteri ATCC PTA 5289 after encapsulation through spray drying. The bacterial cells were assessed and visualized by Scanning Electron Microscopy (SEM) and Light Microscopy (LM) as well as spectrophotometry. L. reuteri ATCC PTA 5289 showed stable growth on polystyrene surfaces and adherence was also observed on aluminium surfaces. SEM images demonstrated morphological changes of the bacteria that occurred during the spray drying. After spray drying the preparation showed 15 % viable cells. The survival percentage of the spray-dried end product after 4 weeks of storage was approximately 33 % when stored at 5 °C, compared to 5 % at 25 °C.