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 | |
|---|---|
|
 |
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's Wellness Encyclopedia |
| Let Food Be Thy Medicine Medicine Thy Food - Hippocrates |
Translate this page: - East Asian
中文,
日本,
한국어,
South Asian
हिन्दी,
தமிழ்,
తెలుగు,
Urdu,
ಕನ್ನಡ,
Southeast Asian
Indonesian,
Vietnamese,
Thai,
မြန်မာဘာသာ,
বাংলা
European
español,
Deutsch,
français,
Greek,
português do Brasil,
polski,
română,
русский,
Nederlands,
norsk,
svenska,
suomi,
Italian
Middle Eastern & African
عربى,
Turkish,
Persian,
Hebrew,
Afrikaans,
isiZulu,
Kiswahili,
Other
Bulgarian,
Hungarian,
Czech,
Swedish,
മലയാളം,
मराठी,
ਪੰਜਾਬੀ,
ગુજરાતી,
Portuguese,
Ukrainian
Medical Disclaimer: WikiMD is not a substitute for professional medical advice. The information on WikiMD is provided as an information resource only, may be incorrect, outdated or misleading, and is not to be used or relied on for any diagnostic or treatment purposes. Please consult your health care provider before making any healthcare decisions or for guidance about a specific medical condition. WikiMD expressly disclaims responsibility, and shall have no liability, for any damages, loss, injury, or liability whatsoever suffered as a result of your reliance on the information contained in this site. By visiting this site you agree to the foregoing terms and conditions, which may from time to time be changed or supplemented by WikiMD. If you do not agree to the foregoing terms and conditions, you should not enter or use this site. 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
