Agglomerated microbiological media

1. A method of making a flowable, dried agglomerated nutrient medium, the method comprising:

introducing a nutrient component comprising a powdered nutrient, and an agglomeration liquid, into an agglomerator comprising a flow-through-type agglomeration chamber and a mixing blade;

wherein the nutrient component facilitates the growth of a microorganism;

wherein the agglomeration liquid is introduced as an atomized spray;

wherein introducing the nutrient component into the agglomeration chamber comprises introducing the nutrient component at a feed rate of about 50 kg/hour to about 1000 kg/hour;

wherein introducing the agglomeration liquid into the agglomeration chamber comprises introducing the agglomeration liquid at a spray rate about 15 kg/hour to about 300 kg/hour;

wet-massing the nutrient component with the agglomeration liquid in the agglomeration chamber for a period of time to form agglomerated nutrient medium particles;

exposing the agglomerated nutrient medium particles to drying conditions for a period of time to form the dried, agglomerated nutrient medium;

wherein the mixing blade is rotated at a blade rotation rate of about 500 rpm to about 4000 rpm;

wherein exposing the agglomerated nutrient medium to drying conditions comprises exposing the agglomerated nutrient medium to a temperature of about 60° C. to about 85° C.;

wherein the feed rate, the spray rate, the blade rotation rate, and the temperature are selected to produce a dried agglomerated nutrient medium having particles of a first particle size distribution range of about 105 microns to about 2000 microns; and

isolating a subpopulation of the particles, the subpopulation having a second particle size distribution range that is narrower than the first particle size distribution range, the second particle size distribution range being about 149 microns to 1000 microns;

wherein the powdered nutrient is capable of being rehydrated to produce buffered peptone water, trypticase soy broth, lactose broth, UVM modified Listeria enrichment broth, buffered listeria enrichment broth, or Demi-Fraser broth.

2. The method of claim 1 , wherein the agglomeration liquid consists of water.

3. The method of claim 1 , wherein the agglomeration liquid comprises a solvent having a dissolved nutrient that facilitates the growth of a microorganism.

4. The method of claim 1 , wherein introducing a nutrient component comprises introducing a substantially uniform mixture of two or more powdered nutrients.

5. The method of claim 1 , wherein one or more powdered nutrient is selected from the group consisting of a protein, a carbohydrate, a salt and a mixture of any two or more of the foregoing powdered nutrients.

6. The method of claim 1 , further comprising the step of subjecting the dried agglomerated nutrient medium to a process that reduces the number of viable microorganisms in the dried agglomerated nutrient medium.

7. The method of claim 6 wherein subjecting the dried agglomerated nutrient medium to a process that reduces the number of viable microorganisms comprises exposing the dried agglomerated nutrient medium to ionizing radiation or to ethylene oxide vapor.

8. A method of making a thin film culture device, comprising

making a flowable, dried agglomerated nutrient medium according to the method of claim 1 ; and

disposing the flowable, dried agglomerated nutrient medium on an adhesive layer of a self-supporting waterproof substrate having first and second major surfaces and an adhesive layer that is disposed on at least a portion of the first major surface such that the flowable, dried agglomerated nutrient medium is in fluidic contact with a dry, cold-water gelling agent.

9. The method of claim 8 , wherein a cover sheet is coupled to at least a portion of the self-supporting waterproof substrate.

10. The method of claim 9 , wherein the cover sheet has a first side facing the first major surface, and further wherein at least some of the dry, cold-water gelling agent is adhered to at least a portion of a first side of the cover sheet.