Chopped Meat Carbohydrate Broth, PR II (pre-reduced medium in Hungate tubes) is a general-purpose medium for the enrichment and cultivation of anaerobic microorganisms, particularly obligate anaerobes.

Chopped Meat Carbohydrate Broth, PR II (pre-reduced) is a general enrichment broth medium that supports growth of most anaerobes, provides a backup source of culture material if an anaerobic jar or chamber fails and for enrichment of small numbers of organisms.¹ It may be used for subculture and enrichment of anaerobic isolates for chromatographic analysis and tests to determine proteolysis (meat digestion), spore formation, motility and toxin production, particularly by Clostridium species, and as a holding or stock culture maintenance medium.²

The use of Chopped Meat Carbohydrate Broth, PR II is based on Hungate's methods of culturing anaerobic microorganisms outside of an anaerobic chamber.³ The tubes provide a reduced medium in a self-contained, anaerobic culture tube sealed using a Hungate screw cap. The cap contains a butyl rubber septum stopper that permits inoculation and incubation without exposing the medium to air.