BacterTest™ Methyl red

INTENDED USE

BacterTest™ Methyl Red is used in the Methyl Red (MR) test, part of the MR-VP test kit, to detect a bacterium’s ability to ferment glucose and produce acids. The MR test helps differentiate bacterial species, particularly between those in the Enterobacteriaceae family, such as Escherichia coli (MR positive) and Enterobacter (MR negative).

PRINCIPLES

Methyl Red reagent is a pH indicator that changes color from red (pH below 4.4) to yellow (pH above 6.2). In the MR test, bacteria ferment glucose to produce strong acids such as lactic acid, acetic acid, and formic acid. If bacteria produce enough acid, the pH of the medium will drop, and the Methyl Red reagent will turn red.

Enrich the bacterial sample to be tested for 18 – 24 hours.
Prepare a bacterial suspension of 0.5 McFarland in sterile saline. Pipette 200 µL of the bacterial suspension and directly inoculate the bacteria onto the MR-VP medium.
Incubate the sample at 35 – 37°C for 18 – 24 hours.
Add Methyl Red reagent onto the surface of the sample and observe any color changes.

RESULTS

BacterLab ensures the quality of each product batch by testing with ATCC reference strains: