This article introduces equipment for testing and counting coliform bacteria. The equipment can meet the needs of the testing and counting coliforms.
1. MPN Counting Method for Coliform
1.1 Operation Steps for MPN Counting of Coliforms
1.2 Instruction of Operation for MPN Counting of Coliforms
If bacteria are present on the medium but no gas is generated, the coliform flora is negative. However, further analysis is needed to determine whether the types of these bacteria are harmful to the human body. Find out what caused these bacteria.
2. Plate Media Counting Method for Coliforms
2.1 Operation Steps for Plate Counting of Coliforms
2.2 Instruction of Operation for Plate Counting of Coliform
• If there are colonies on the plate medium, but later re-verification does not generate gas. Although it is negative for the coliform flora, further analysis and testing are needed to determine whether the type of bacteria is harmful to the human body.
• Calculation of coliform bacteria: N = A × (C / B) × T
Among them:
N ---- The number of coliforms bacteria
A ---- The number of colonies on the plate medium. Count with an automatic colony counter or manually.
B ---- The number that pick the colonies from the plate culture medium and inoculate into BGLB broth test tube medium, when re-verifying. Generally 10 or less. Use an inoculation loop or inoculation needle to pick colonies and inoculate.
C ---- The number of BGLB broth test tube culture medium that generate gas during re-verification
T ---- Multiples of sample dilution
3. Cautions for Operation of Coliform Counting
4. Equipment and instruments for testing and counting coliforms
4.1 Automatic colony counter: Photograph, analyze and count colonies on plate culture media.
4.2 PSB Biochemical Incubators for Laboratory: The sample is subjected to microbial culture. Temperature accuracy is ±1℃. There are cooling and heating functions.
4.3 Benchtop Water Baths for Laboratory: Some samples are better for microbial culture in a constant temperature water bath. Temperature accuracy is ±1℃. It can also be used in Water Bath Orbital Shakers for Laboratory or Laboratory Refrigeration and Heating Circulating Water Bath Chiller or Water Bath of Three Independent Temperatures for Laboratory.
4.4 Laboratory Analytical Balances or Precision Balances: Accurately weigh the sample.
4.5 Benchtop pH Meter Tester: Measure the pH of the sample or culture.
4.6 Sterilized SCO-1 Sanitary Cans Opener: It does not destroy the double seam when open the lid of the can.
4.7 JV1 Clean Benches or Class 100 sterile laboratory (clean room): The operation is carried out in a clean environment, that is aseptic operation.
4.8 Pipettors or Micropipettes Autoclavable or Pasteur Pipettes and Disposable Droppers or glass pipette: Remove the liquid from the sample.
4.9 PYM-01 Glass Petri Dishes for Cell Culture or Glass Test Tubes with Rim Roll or Ordinary Glass Erlenmeyers and Conical Flasks: For the production of media.
4.10 Metal inoculation Loops and handles: Can pick, transfer and inoculate microorganisms during inoculation. The metal inoculation loop can be reused after sterilization.
4.11 Infrared Sterilizers for Inoculation Loops and Needles: Uses electric heating to sterilize the inoculation loop and needle. The infrared inoculation sterilizer has no open flame and is not afraid of wind, is practical testing equipment of microbiology.
4.12 If you need other laboratory equipment, please browse the “Laboratory Equipment and Instruments”, “Chemistry Laboratory Glassware”, “Food Safety Testing and Inspection Equipment” or “Can Testing Equipment Instruments”.
5. Note
• To learn more about the principles of coliform testing and counting, you can read " Testing and Counting Method of Coliform Bacteria".
• In most countries, there are clear regulations on the methods for the testing and counting of coliforms, but the regulations may differ from country to country. This article mainly refers to the relevant inspection specifications of the People's Republic of China and is for reference only.
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