Mass catering establishments involve a number of threats related to the health safety of the foodproduced there. The most important microbiological threats include: viruses, prions, bacteria,moulds as well as their toxins and parasites. Those biological hazards pose a hazard for peopleoccupied in the food production process and also for consumers. The required microbiologicalquality of meals served in catering facilities is very important given the risk of potential collectivefood poisoning. The aim of the article is to assess the microbiological cleanliness of surfaces,staff hands and technological equipment used in food production, taking into account selectedmicroclimate parameters. Three mass catering establishments were studied, one open and twoclosed. Microbiological purity tests of surfaces intended for food production were carried out usingthe 3M™ Clean Trace™ NGi luminometer and the compact AXIOMET AX-DT100 microclimaterecorder, equipped with an accurate air temperature and humidity sensor. The obtained researchresults were then compared with reference values and a plan was proposed to improve hygienicconditions in the catering establishments in question. A review of the results of studies carriedout on microbiological cleanliness in selected mass catering establishments showed acceptableexceedances of the reference contamination limits.