Measurement method for viable cell count, and culture medium

摘要

There are provided a method of identifying the longum species alone, such as Bifidobacterium longum subsp. longum alone, and measuring the viable cell count thereof, amongst the bacterial cells to be tested which include a microorganism belonging to the genus Bifidobacterium by using a culture medium that contains L-arabinose as a sole sugar source; and also a culture medium which is useful as a selective medium for the above measurement method and which is also easy to prepare.

主权项

1. A method for distinguishing Bifidobacterium longum subsp. longum from at least one of Bifidobacterium breve, Bifidobacterium animalis subsp. lactis, and Bifidobacterium longum subsp. infantis comprising: culturing microorganisms that include Bifidobacterium longum subsp. longum and at least one other microorganism selected from the group consisting of Bifidobacterium breve, Bifidobacterium animalis subsp. lactis, and Bifidobacterium longum subsp. infantis on a culture medium agar for at least 48 hours at a temperature of 37° C. under anaerobic conditions, measuring colonies produced, and only counting colonies having a diameter of 0.7 mm or larger to generate a cell count for Bifidobacterium longum subsp. longum, wherein said culture medium agar is free of magnesium sulfate and manganese sulfate and comprises L-arabinose as a sole sugar source with a concentration of 2 to 3% by mass, relative to the total mass of the culture medium agar, 6.0 to 14.0 g/1,000 mL of peptone, 6.0 to 14.0 g/1,000 mL of a meat extract, and 1.8 to 4.2 g/1,000 mL of a yeast extract.