Compact Dry CF Coliform plates | Compact Dry CF Coliform | Shimadzu

1. Overview of Coliform bacteria

- Coliforms are gram-negative, facultatively anaerobic, non-spore-forming bacteria that are commonly found in the intestines and in the soil of animals. The term “coliform” refers to enteric bacteria found in foods such as meat, shellfish, dairy products, other foods and especially water.

- Bacteria such as Shigella, Salmonella, Yersinia, Citrobacter, Klebsiella and Enterobacter are all coliforms, but the most widely recognised coliform is Escherichia coli . Testing for the presence of coliforms is very important in the food industry, especially in monitoring water quality.

– For that reason, a Coliform testing procedure is recommended, and the Compact Dry Coliform plate offers convenience to the user because it does not require the preparation of culture media, complex equipment or consumables. All the technology used in this Compact Dry Coliform plate is a pre-poured freeze-dried agar medium. The user only has to extract the sample, pipette it onto the plate and incubate it.

2. Advantages of using the Compact Dry CF Coliform plate

- CompactDry CF is a ready-to-use dehydrated culture medium plate for the detection of coliform bacteria in food and beverages. Coliform bacteria are an indicator of the presence of enteric pathogens in water, meat, seafood, dairy products and other foods.
- The monitoring and identification of coliforms is used at every step of the food production process as a quality control parameter. The CompactDry CF selective medium contains the chromogenic enzyme substrate X-Gal, which produces blue to blue/green colonies. CompactDry CF allows easy cultivation and counting of coliforms in solid foods (homogenised with buffer), water/liquid samples and swab-based environmental testing of surfaces and production areas.
– Simple procedure that is easy to use, with no need for consumables or complex equipment.
– Easy to use and no time lost training users.
– The compact dry plate is easy to store thanks to its packaging of 4 plates in 1 pack.
– The results are quite accurate, easy to analyse and available after 24 hours.
– Colonies can be isolated for biochemical testing.

3. Testing procedure on the Compact Dry CF Coliform plate

- Prepare a suitable diluent solution. Butterfield’s phosphate buffered diluent (BPBD), Maximum recovery diluent (MRD).

- Weigh 10g of solid sample and add 90mL of Butterfield’s buffered phosphate diluent (BPBD) or Maximum Recovery Diluent (MRD) to the sample. Homogenise this mixture with a stomacher.

- Open the lid and use a sterile pipette to place 1ml of the test sample, if it is a liquid product, or of the appropriate dilutions, in the centre of each Compact Dry CF plate. Work with 2 consecutive dilutions, 2 plates per dilution. The sample diffuses automatically and spreads evenly over the plate surface.

- Close the plate lid and write the necessary information in the notes section.

- Incubate the sample: Incubation time: 24 ± 2 hours, Incubation temperature: 35 ± 2°C or 37 ± 1°C

* Read the results and count the colonies

- Choose plates with 10-150 colonies.
- Blue and blue/green colonies are Coliform

* The procedure is illustrated as follows:

* Note

- A plate with more than 250 CFU may make the whole colony growth area difficult to read. In this case the sample must be diluted.

- After reading the result, autoclave the plate (121 °C / 30 minutes) before disposal.