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Minimum Inhibitory Concentration Test (MIC)

The Minimum Inhibitory Concentration (MIC) test is a well-established assay for the biostatic (growth-inhibiting) activity of liquid antimicrobials. It is rapid, relatively inexpensive, and reliable.

Below, you will find a summary of the MIC test procedure, along with some of its strengths and weaknesses. In addtion, the photos below expand to full size diagrams.

Labeled Photo of Microtiter MIC Test

Labeled Photo of Standard MIC Test -

Layperson's Summary

To do an MIC, one inoculates the test substance with an invisible, but high number of microorganisms, then observes the mixture of microorganisms and test substance to see if it changes from clear to cloudy. If it turns cloudy, that means microorganisms have grown to high levels and the test substance is not inhibitory to them at that particular dilution.

Test wells that remain clear after incubation may contain the original low-level inoculum of viable microorganisms, or the microbes could all have been killed by the antimicrobial agent. Those two outcomes cannot be differentiated visually. For that reason, scientists use MIC assays as indicators of an antimicrobial agent's inhibitory activity rather than biocidal activity.

Summary of the Minimum Inhibitory Concentration Test (MIC Test):

Strengths of the Minimum Inhibitory Concentration Test (MIC Test):

Weaknesses of the Minimum Inhibitory Concentration Test (MIC Test):

MIC tests are an important and unique part of Antimicrobial Test Laboratories' portfolio of testing services. MIC tests are especially appropriate if liquid antimicrobial agents will be used to inhibit the growth of microorganisms in some context.

If you are ready to set up a study, just get a price quote. For more information about MIC testing services, Contact the Lab Today!