Dear Stanley: Thermotolerant Strains for Fecal Coliform Testing

Dear Stanley,

Do you know of any Escherichia coli and Klebsiella pneumoniae strains that will grow at 44.5°C? I need thermotolerant controls for my fecal coliform test.

Angie from Rochester, NY

Dear Angie,

Microbiologics has a document that can help you find the right strains for your fecal coliform test: Quality Control for Water Testing.  The document lists:

  • Thermotolerant strains of E. coli and K. pneumoniae
  • Strains of Aerococcus, Enterobacter, Enterococcus, Kocuria, Legionella, Proteus, Serratia, and Staphylococcus as well as several more strains of Escherichia and Klebsiella used in water testing
  • The quality control microorganism strains recommended by the U.S. Environmental Protection Agency (EPA) Manual for Certification of Laboratories Analyzing Drinking Water, Standard Methods for the Examination of Water and Wastewater, and ISO 11133 Microbiology of Food, Animal Feed and Water
  • Click here to download the document

The following thermotolerant strains are listed in the document and are available in Microbiologics KWIK-STIK™ and LYFO DISK™ formats

Thermotolerant Strain Microbiologics Catalog Number
Escherichia coli derived from ATCC® 11775* 0465
Klebsiella pneumoniae subsp. pneumoniae derived from ATCC® 27736™* 0685
Klebsiella variicola derived from ATCC® 31488™* (formerly Klebsiella pneumoniae subsp. pneumoniae) 0261
Klebsiella pneumoniae subsp. pneumoniae derived from ATCC® 33495* 0957

I also have a few tips for performing a fecal coliform test at 44.5°C:

  1. Use a circulating water bath with a gable cover. The temperature should be 44.5°C ± 2°C.
  2. Check your records to see when you last calibrated your thermometers. Glass and electronic thermometers should be calibrated annually to ensure measurements are precise. See the EPA Manual for the Certification of Laboratories Analyzing Drinking Water, Chapter 5, for more information regarding the calibration of thermometers.
  3. Use a long wave UV light (365-366 nm) to test for fluorescence.

Visit our website to find water testing controls in several easy-to-use formats. Our experienced Technical Support team is available to help you find the right strain and format for your lab, or to answer your QC questions. You can reach them at 1.320.229.7045 or



Stanley Staphylococcus is a Master Micro-Technologist at Microbiologics, where he is responsible for helping customers understand why microorganisms behave the way they do. You could say he’s somewhat of a psychologist. Microbiologics has been lucky to have Stanley, a graduate of Gram-Positive Cocci University, as a member of their renowned Technical Support Team for over 20 years. Stanley says his favorite type of people are microbiologists and he enjoys traveling far and wide to meet them. Amazingly, Stanley has been on every continent – even Antarctica!

How to submit inquiries: There are two ways to get Stanley’s help. You can email your questions to or you can simply submit an inquiry from our Dear Stanley page. For urgent issues, please contact our Technical Support Team at or 1.320.229.7045.

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