Colony count
Colony Count is a method used in microbiology to estimate the number of viable bacteria or fungi in a sample. It is a crucial technique in clinical microbiology, food microbiology, and water microbiology.
Overview[edit | edit source]
The colony count method involves spreading a known volume of a sample onto a petri dish containing a suitable growth medium. After incubation, the number of colonies that have grown on the dish is counted. Each colony is assumed to have originated from a single microorganism, so the number of colonies gives an estimate of the number of viable organisms in the original sample.
Procedure[edit | edit source]
The procedure for a colony count typically involves several steps:
- Sample Preparation: The sample is prepared by diluting it to a suitable concentration. This is often done using a series of serial dilutions.
- Plating: A known volume of the diluted sample is spread onto a petri dish containing a suitable growth medium.
- Incubation: The petri dish is incubated at a temperature that promotes growth of the organisms of interest.
- Counting: After incubation, the number of colonies on the dish is counted. This count is then used to calculate the number of viable organisms in the original sample.
Applications[edit | edit source]
Colony counts are used in a variety of fields:
- Clinical Microbiology: Colony counts are used to diagnose infections by identifying and quantifying the bacteria or fungi present in clinical samples.
- Food Microbiology: Colony counts are used to assess the microbial contamination of food products.
- Water Microbiology: Colony counts are used to monitor the microbial quality of drinking water and recreational waters.
Limitations[edit | edit source]
While the colony count method is widely used, it has several limitations. It only estimates the number of viable organisms, and does not give information about non-viable organisms or those that are viable but not culturable on the growth medium used. It also assumes that each colony arises from a single organism, which may not always be the case.
Colony count Resources | ||
---|---|---|
|
|
Navigation: Wellness - Encyclopedia - Health topics - Disease Index - Drugs - World Directory - Gray's Anatomy - Keto diet - Recipes
Search WikiMD
Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro / Zepbound) available.
Advertise on WikiMD
WikiMD is not a substitute for professional medical advice. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates Wikipedia, licensed under CC BY SA or similar.Contributors: Prab R. Tumpati, MD