The Heterotrophic Plate Count assay, formerly known as the Standard Plate Count assay, is used primarily to monitor the Heterotrophic bacterial load present in a water sample. Heterotrophic organisms are any organism that obtains nutrients by feeding off of the compounds in the water. Several manufacturing processes require the use of treated water in order to control the amount of microbes exposed to a particular product. In well controlled facilities, water that is used in making reagents and water used for cleaning automated machines is required to be tested and monitored on a regular basis.

Test Method

To test water samples for their Heterotrophic microbial load, we use the membrane filtration test method. In this method a water sample is submitted and then filtered through a filter membrane. The filter is rinsed to remove bacteriostatic / fungistatic contaminants that might be present. Then the filter is aseptically transferred to plated Heterotrophic agar media and incubated for 48 hours at 37^oC.

The visible colonies, grown from clusters, chains and single cells of the Heterotrophic bacteria, that were present in the sample show up on the media and are quantified as total CFUs, colony forming units. This number is then reported in the final report that is mailed to the specified contact.

How To Begin Heterotrophic Plate Count Testing

To begin testing your water samples using the Heterotrophic Plate Count assay; our Services Department must receive a sample of the product. Since the results of this assay depend on counts of viable bacteria cells, we strongly recommend that MO BIO Laboratories, Inc.’s Services Department receive samples no more than 24 hours after the sample was taken. All samples should be shipped overnight at ambient temperature. DO NOT FREEZE. Please notify MO BIO Laboratories, Inc. before you plan to ship samples so that adequate planning is assured.

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You and your company decide upon a testing schedule that best fits the needs of your particular product. MO BIO Laboratories, Inc. can work with you to design a testing schedule that accomplishes this goal. Click here for more information.

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