IDEXX: EasyDisc* YEA Test Kit:  The EasyDisc YEA (98-0013452-00, 98-0013453-00) method is used for the quantification of culturable, waterborne bacteria. Culturable is defined as any aerobic bacteria able to form colonies on solid media. It is based on colorimetric technology which detects viable aerobic bacteria by testing for growth and for the presence of key enzymes known to be present in these organisms.

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Official Method Name
 IDEXX EasyDisc* YEA
Current Revision
Initial submission
Media
 WATER
Instrumentation
 Plate Count
Method Subcategory
 Microbiological
Method Source
  IDEXX
Citation
  Water quality — Enumeration of culturable micro-organisms — Colony count by inoculation in a nutrient agar culture medium
Brief Method Summary
 1. Remove white lid and add 1±0.1 mL water sample directly to the clear EasyDisc YEA plate. 2. Gently swirl immediately after sample addition to coat the plate entirely and reattach white lid. 3. Incubate undisturbed at room temperature for at least 20 minutes to allow for the media to set. Transfer plate to incubator within 1 hour of sample addition. 4. Incubate the plate, white lid side up, in a 22±2°C incubator for 68±4 hours or in a 36±2°C incubator for 44±4 hours. Inoculate at least one plate for incubation at each temperature. 5. Examine the plates for colony growth as soon as they are removed from the incubators. Reject any plate with confluent growth. 6. Sum all colonies for the result. The result is expressed as colony forming units (CFU) per milliliter. NOTE: Most microorganisms will produce a blue color on EasyDisc, but some may produce natural pigments with colors other than blue. All colonies should be summed for the final result.
Scope and Application
 Detection and quantification of Heterotrophic bacteria. Appropriate matrices include drinking water, process water, bottled water, and other non-potable waters
Applicable Concentration Range
Interferences
 Chlorinated samples should be treated with sodium thiosulfate prior to testing, preferably upon sample collection
Quality Control Requirements
Sample Handling
Maximum Holding Time
Relative Cost
Sample Preparation Methods
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