Water-reconstitutable culture medium resistant to liquefaction by microorganisms

A device for growing microorganisms, comprising:

• a body member comprising a self-supporting, water-proof substrate having upper and lower surfaces;
• a layer of adhesive disposed on the upper surface of the substrate, the adhesive being non-inhibitory to the growth of microorganisms;
• a cold-water-soluble powder adhered to the adhesive, the powder comprising:
• a cold-water-soluble gelling agent;
• one or more nutrients for growing microorganisms;
• a cover sheet having an inner-facing surface and an outer-facing surface, the cover sheet adhered to at least a portion of the body member;
• and
• a dry composition comprising a mixture of hydroxypropylmethylcellulose and guar gum adhered to the inner-facing surface of the cover sheet or the upper surface of bottom substrate;
• wherein the device includes a microbial growth zone disposed between the substrate and the cover sheet;
• wherein the microbial growth zone is free of matrixes that prevent visualization of bacterial colonies;
• wherein the cover sheet is adhered to the body member so that the upper surface of the substrate faces the inner-facing surface of the cover sheet.