Goal of this thesis was to check the microbiological cleanness of flour. Microbiological analyzes were performed on flour samples in the laboratory. Samples of flour T-550 and T-850 were tested for: aerobic mesophilic bacteria, yeasts and molds, Enterobacteriaceae and mycotoxins of molds. The microbiological analysis of the flour is carried out on the basis of one sample, and therefore lower value of maximum allowed concentration (MAC) is taken. Aerobic mesophilic bacteria are bacteria which grow in the temperature range of 20 – 45 °C in pressence of oxygen. Increased number of aerobic mesophilic bacteria in flour shows that flour has poorer microbiological quality. Molds are yeasts belong to the empire of fungi. Many types of molds do not present a danger to human health, but some produce mycotoxins which are toxic to humans and may cause a cancer. Like molds, yeasts could be air borne and so they can come on the surface of foods, but majority of them do not pose a threat to human health. Bacteria from Enterobacteriaceae family are very widespread, and many of them can cause disorders and diseases of humans. That is why the determination of these bacteria in foods and raw materials is of great importance. Mycotoxins are toxic metabolites of some species of molds. Therefore, laboratory control of food is necessary by using analytical methods which are used to check health safety.