Compact Dry Total Viable Count plates | Compact Dry TC Total Viable Count | Shimadzu

1. Overview of the total aerobic count

- Aerobic microorganisms are microorganisms that need molecular oxygen to survive and grow, and that form colonies when cultured. However, they require a lower percentage of oxygen in their living environment than in the normal atmosphere.
- All the microorganisms present in a sample that can tolerate the presence of oxygen, but have no specific growth requirements, are usually not included in the media formulations.

- According to the Food and Drug Administration (FDA), the total aerobic count is considered one of the typical and representative parameters for foods (frozen, chilled, pre-prepared and ready-to-eat foods) and for pharmaceutical samples.

- For this reason, a test procedure for the total aerobic count is recommended; and the Compact Dry Total Viable Count plate brings convenience to the user thanks to the advantage of not requiring the preparation of culture media chemicals, equipment or complex consumables.
- The whole technology used for this Compact Dry Total Viable Count plate is a pre-poured medium. The user only has to extract the sample, pipette the sample onto the plate and take it to incubation.

* Applications on samples:

– Liquid samples: wastewater, domestic water...
– Solid samples: animal feed, milk, milk powder, meat, fish, shrimp...

2. Advantages of using the Compact Dry Total Viable Count plate

– Simple procedure that is easy to use, with no need to prepare consumables or complex equipment.
– Easy to use and no time lost on training users.
– The compact dry plate is easy to store thanks to its packaging of 4 plates per pack.
– Reasonably accurate, easy to analyse and results are available after 48 hours.
– Colonies can be picked for biochemical testing.

3. Test procedure on the Compact Dry Total Viable Count plate

– Aseptically weigh 10.0 g of sample, or use a pipette to take 10.0 ml (for samples that are a solution), and place it in a suitable sterile container (for example a sterile sample bag, a dilution bottle or a Whirl Park bag).
– Add 90.0 ml of diluent to reach a 1:10 dilution and homogenise the sample. Adjust the pH if necessary. The diluent usually recommended is Butterfield's phosphate buffer, maximum recovery diluent and other suitable diluents depending on BAM. If necessary, the sample can be diluted further.
– Open the lid of the Compact Dry plate. Take 1.0 ml of the diluted sample with a micropipette and place it in the middle of the Compact Dry plate. Close the lid of the plate.
– Invert and incubate the compact dry plate under the specific incubation conditions (Per AOAC International standard: 35 ± 2°C for 48 ± 3 hours, per Microval and NordVal standards: 30 ± 1°C for 48 ± 3 hours).

* Reading the results and counting the colonies

- Choose plates with 10-150 colonies.
- Red colonies or colourless colonies.

* The procedure for handling the Compact Dry TC plate is described in pictures as follows:

Note:

- Some colonies may not have a clear red colour.

- A plate with more than 300 CFU may make the whole colony area turn red/pink. In this case the sample has to be diluted.

- After the results have been read, the plate is sterilised in an autoclave (121 °C/ 30 minutes) before it is disposed of.