PRD- Phenol Red Dextrose

The NACE standard (TMO194-2004) Media used for the detection of aerobic and facultative Acid Producing Bacteria (APB), as well as General Heterotrophic Bacteria(GHB). As APB grow and metabolize in the media, the organic acids they produce facilitate a drop in pH. Because of this change in pH, the media will change colors from red to orange/yellow. The color change is also accompanied by visible turbidity or biomass in the media. General Heterotophic Bacteria can also grow in this media but will not facilitate a color change. GHB can be identified in the vials by visually identifying turbidity or biomass.

False Positive: If the vials turn yellow immediately upon injection, the color change is due to the low pH of the sample fluids, not biogenic activity. If the questionable positive media is perfectly clear even though the yellow color change has taken place, this is likely due to contamination and not bacterial activity. If acid producing bacteria are present in the vial, turbidity (cloudiness) of the media will be apparent visually.

Physical Characteristics: Bright to Dark red in color.