SimPlate for HPC

Heterotrophic plate counts simplified


Easy-to-count wells on a round plate that correlates to plate count agar. Positives fluoresce under UV light.



  • Easier to read and use than the pour-plate method.
  • No agar preparation.
  • Most Probable Number (MPN) counting range minimizes need for dilutions.

  • Instant media preparation.
  • Less than 2 minutes of hands-on time.
  • Reduced read time.
  • Correlates with U.S. EPA-approved, pour-plate method1using plate count agar and 48-hour, 35°C incubation.2
  • Simplified procedure minimizes chance of contamination.
  • Less subjective interpretation than pour plate.
  • Less equipment to purchase and maintain.
  • Increased productivity saves labor costs.
  • Minimal Quality Control (QC).


How SimPlate for HPC works

Multiple Enzyme Technology Medium—the SimPlate for HPC medium uses IDEXX Multiple Enzyme Technology (MET) to detect heterotrophic plate count (HPC) bacteria in water. The reagent contains multiple unique enzyme substrates, each targeting a different bacterial enzyme. The most common enzymes of waterborne bacteria are all targeted.

All of the enzyme substrates produce the same signal when metabolized. Therefore, a given waterborne bacteria will be able to metabolize one or more enzyme substrates and produce a signal. In the case of SimPlate for HPC, the signal is fluorescence under 365 nm UV light.

After the sample and medium are added to the plate, the wells fill automatically as the user swirls the plate. No pipetting is needed.

Once the wells are filled, the plate is angled and excess sample/medium mixture is poured into the absorbent pad. The SimPlate takes advantage of surface tension to hold the proper amount of sample/medium mixture in each of its 84 wells as excess is poured off.

SimPlates are incubated upside down to prevent condensation from collecting on the lid. Since each well is isolated from the others, bacteria from one well will cause only that one well to fluoresce.

The number of wells that fluoresce is converted to a Most Probable Number (MPN) using the table provided with the product. The high number of wells (84) results in a very high counting range and precise 95% confidence limits. The counting range is from <1 to 738 per plate (more than double a standard pour plate) with the multi-dose SimPlate for HPC.


Step 1

Add 100 mL sterile diluent to media vessel.

Step 2

Add 1 mL sample to SimPlate.

Step 3

Add 9 mL media to SimPlate.

Step 4

Swirl SimPlate and pour off excess.

Step 5

Invert and incubate for 48 hours.

Step 6

Read results under UV light.

Frequently asked questions

Is SimPlate for HPC approved by the U.S. EPA?

Yes. SimPlate for HPC is U.S. Environmental Protection Agency (EPA) approved for compliance monitoring of drinking water, effective November 29, 2002.

What is the shelf life of SimPlate for HPC?

The shelf life is up to 15 months from date of manufacture.

What is the U.S. EPA threshold for HPC in drinking water?

As per the 40CFR Part 141.72, surface water systems must provide disinfection at the point of entry whether the water is filtered or not. The distribution system water must have a detectable level of disinfectant or an HPC level less than or equal to 500/mL.

What are the recommended storage conditions for SimPlate for HPC?

Store at 2°C–30°C and away from light.

Are SimPlates sterile?

Yes, the base and lid are gamma irradiated. There are 25 plates per plastic sleeve. Any unused plates should remain in the bag and the bag should be closed. Do not leave any unused plates exposed to the environment.

Are SimPlates made of recyclable plastic?

The bottom portion of the plate is made of polystyrene #6 and is recyclable. The cover/lid is made of polyvinyl chloride and is not recyclable.