scope:

This International Standard specifies a method for the measurement of the acidification activity of lactic acid bacteria by continuous measurement of pH.

NOTE The method is based on Reference [9].

The method is applicable to dairy starter cultures where these characteristic microorganisms are present.

Two types of standardized milk are specified in the procedure: boiled milk with 9,5 % mass fraction dry matter (B-milk 9,5); and autoclaved milk with 9,5 % mass fraction dry matter (A-milk 9,5). It is possible that heat treatment of B-milk 9,5 does not inactivate all enzymes that are present, which can affect the activity of some cultures. In that case, cultures are tested with A-milk 9,5 in which all enzymes have been inactivated.