Anaerobic Agar 1000 Condalab

Anaerobic Agar is used for the cultivation of anaerobic microorganisms. Anaerobic bacteria are unable to use oxygen as a terminal acceptor. Casein peptone and soy peptone provide nitrogen, vitamins, minerals, and amino acids that are essential for growth. Dextrose is the fermentable carbohydrate that provides carbon and energy. Sodium thioglycolate and sodium formaldehyde sulfoxylate act as reducing agents that generate a low oxidation reduction potential which secures good anaerobic conditions. Methylene blue acts as the redox indicator as the blue colour indicates the presence of oxygen.

The testing procedures are carried out using standard Petri dishes or Brewer’s Anaerobic Agar Plates, both with the medium cooled to 45-50 ºC. The seeding of the sample can be performed by surface inoculation or by pour plate method. Normally the sample should never be heated to destroy the vegetative forms of the aerobe, as the anaerobic non-spore formers will also be destroyed. Nevertheless, sometimes it could be useful to heat the sample when spore formers such as Clostridium are sought, except C. perfringens, which rarely forms spores. When heating is indicated, warm the sample suspended in a liquid diluent (peptone water, buffering phosphate solution, etc.) to 70-80 ºC for 10 minutes. The plates of Anaerobic Agar can also be incubated in a normal atmosphere covering the surface of the plates with a Brewerlid. When growth is observed, open the plate, and pick the desired colonies. Incubate longer if necessary. If the medium has not been prepared fresh before use, it is necessary to heat and remelt to expel the dissolved oxygen. Thioglycollate Medium without Indicator is an excellent enrichment broth and, frequently using it previously, yields better results than direct seeding.