Division 2.1.2 ProductionF1F2

It is obtained from the water-soluble fractions prepared by heating in free-flowing steam and subsequently filtering cultures of M. bovis or M. avium (as appropiate) grown in a liquid synthetic medium. The active fraction of the filtrate, consisting mainly of protein, is isolated by precipitation, washed and re-dissolved. An antimicrobial preservative that does not give rise to false positive reactions, such as phenol, may be added. The final sterile preparation, free from mycobacteria, is distributed aseptically into sterile tamper-proof glass containers which are then closed so as to prevent contamination. The preparation may be freeze-dried.