Compact Dry CF-L Coliform plate | Compact Dry CF-L Coliform | Shimadzu

1. Overview of Coliform bacteria

- Coliforms are gram-negative, facultatively anaerobic, non-spore-forming bacteria commonly found in the intestines of animals and in soil. 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 water quality monitoring.

– For this reason, a Coliform test procedure is recommended, and the Compact Dry Coliform plate offers convenience to the user thanks to the advantage of needing no preparation of culture-media chemicals, equipment or complex consumables. All the technology used for this Compact Dry Coliform plate is a pre-poured freeze-dried agar medium. Users only need to extract the sample, pipette the sample onto the plate and take it for incubation.

2. Benefits of using the Compact Dry CF-L Coliform plate

- CompactDry CF-L is a ready-to-use dehydrated culture-medium plate for detecting coliform bacteria in dairy products such as cheese, milk, yoghurt and any product containing lactic acid bacteria.
- Monitoring and identifying coliforms is an important quality-control parameter throughout food production. The CompactDry CF-L selective medium contains the chromogenic enzyme substrate X-Gal, which produces blue to blue/green colonies, making it easy to culture and count coliforms in dairy products. CompactDry CF-L makes it easy to culture and count coliforms in dairy products.
- It is specially designed to counter the negative effect of lactic acid bacteria on the chromogenic substrate.
– Simple, easy-to-use procedure, no preparation of consumables or complex equipment required.
– Easy to use and no time spent training users.
– The compact dry plate is easy to store thanks to its packaging of 4 plates per pack.
– The results are quite accurate, easy to analyse and available after 24 hours.
– Colonies can be picked for biochemical testing.

3. Test procedure on the Compact Dry CF-L Coliform plate

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

- Weigh 10 g of sample and add 90 mL 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 1 ml of the test sample, if it is a liquid product, or of the suitable dilutions, in the centre of each Compact Dry CF plate. Perform this on 2 successive concentrations with 2 plates per concentration. The sample spreads and distributes itself evenly over the plate surface.

- Close the lid of the plate 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

- The medium contains the chromogenic enzyme substrate X-Gal and coliform colonies are blue.

- The growth of other (background) bacteria is mostly inhibited, but in certain cases colourless colonies may form.

* 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 results, the plate must be autoclaved (121 °C/ 30 minutes) before disposal.