Abstract: The object of the invention is a microbe culture medium which can be activated with a liquid sample or water. Covalently crosslinked cellulose ethers are used as a gelling agent. The gel into which nutrients have been mixed is dried on a water-impermeable support. The culture medium according to the invention may be utilized for detecting bacteria and fungi both in the hygiene control of industry and in medical diagnostics. The same method principle may be used within different sensitivity ranges as the absorption capacity of the gel may be regulated according to the hydrophilicity of cellulose ethers.

Abstract: The present invention provides a method for the pretreatment of object surfaces prior to taking a sample for microbial analysis. The method uses a blend to remove biofilms without hindering the growth of microorganisms. The method allows for reliable and replicable determination of microorganisms formed on the investigated surfaces.

Abstract: The invention comprises a culture medium and method for distinguishing bacteria of Salmonella species from other gram-negative bacteria, especially those belonging to the family Enterobacteriaceae. It is based on the ability of salmonellae to utilize melibiose, mannitol, and sorbitol and convert them into acids, together with a chromogenic substrate used for identifying .beta.-galactosidase. Other bacteria of the family Enterobacteriaceae, most of which are .beta.-galactosidase-positive, appear as brown, blue, or green colonies, depending on the chromogenic substrate used. Apart from Salmonella species, other .beta.-galactosidase-negative bacteria, such as Proteus species, appear as colorless colonies. Salmonellae can be identified directly on the culture medium after incubation, by their characteristic bright red color.

Abstract: A method for determining the presence of microorganisms in a liquid sample. The liquid sample is first filtered through a filter having a pore size which is small enough to prevent passage of microorganisms through the filter but large enough to permit passage of any free reducing agents present in the sample whereby microorganisms present in the sample are retained on the filter. A chromogenic reagent having an oxidation potential such that the reagent can be reduced by microbial dehydrogenase and selected such that reduction of the chromogenic reagent yields a visibly colored product is then passed through the filter, and the filter is monitored for the formation of a visibly colored product indicative of the presence of microorganisms in the sample.

Abstract: The presence of microorganisms in a liquid sample can be determined by a method comprising the steps of (a) filtering the liquid sample through a filter having a pore size which is small enough to prevent passage of microorganisms through the filter but large enough to permit passage of any free reducing agents present in the sample whereby microorganisms present in the sample are retained on the filter; (b) passing a test solution comprising a chromogenic reagent through the filter having the retained microorganisms thereon, said chromogenic reagent having an oxidation potential such that the reagent can be reduced by microbial dehydrogenase and said chromogenic reagent being selected such that reduction of the chromogenic reagent yields a visibly colored product; and (c) monitoring the filter for the formation of a visibly colored product, wherein the formation of a visibly colored product is indicative of the presence of microorganisms in the sample.