**Abstract**

Scientific evidence exists showing that lactic acid bacteria, including the genus *Lactococcus*, have the capacity to bind and remove cholesterol. However, in many cases, in vivo and in vitro results are not unambiguous or reproducible; thus it appeared valid to conduct a study which would explain what factors determine adhesion and assimilation of cholesterol by *Lactococcus*. The study on *Lactococcus* bacteria under in vitro conditions in model digestive fluids may contribute to the explanation of the observed ambiguities. In vitro research has proven that *Lactococcus* is capable of removing free cholesterol under in vitro conditions in broths without bile salts, as well as in a simulated gastric fluid and in the conditions of simulated intestinal fluid. The amount of cholesterol removed by live cells of *Lactococcus* is directly proportionately dependent on the concentration of this substance, incubation temperature, count, and viability of cells. However, oftentimes these relationships are not linear. Under the conditions of model gastric fluid or intestinal fluid, the cultures of *Lactococcus* release portion of the previously bound cholesterol, independent of cell viability. The survival rate of *Lactococcus* cells in simulated gastric fluid or simulated intestinal fluid depends on the tested bacterial culture and does not depend on the presence of cholesterol.

**Keywords:** cholesterol, *Lactococcus*, survival, gastrointestinal tract, duodenum, gastric acid
