DEHYDRATED CULTURE MEDIA 195 



STERILITY TEST MEDIA 



The media listed in this section are recommended for sterility testing. Included 

 are the media specified by the National Institute of Health in its circular "Cul- 

 ture Media for the Sterility Test" 2nd. Rev. February 5, 1946. Media for sterility 

 testing according to the "Compilation of Regulations for Tests and Methods of 

 Assay and Certification of Antibiotic Drugs," Federal Security Agency, Food and 

 Drug Administration and U. S. Pharmacopeia and the National Formulary are 

 also described in this section. 



BACTO 



FLUID THIOGLYGOLLATE MEDIUM (B256) 



DEHYDRATED 



Bacto-Yeast Extract 5 g. 



Bacto-Casitone 15 g. 



Bacto-Dextrose 5 g. 



Sodium Chloride 2.5 g. 



/-Cystine, Difco 0.75 g. 



Thioglycollic Acid 0.3 ml. 



Bacto-Agar 0.75 g. 



Resazurin, Certified 0.001 g. 



Bacto-Fluid Thiogly col late Medium conforms to the formula specified by 

 the National Institute of Health^ for the sterility testing of biologicals and for the 

 sterility testing of antibiotics according to the method of the "Compilation of 

 Regulations for Tests and Methods of Assay and Certification of Antibiotic 

 Drugs," Federal Security Agency, Food and Drug Administration. The medium 

 is prepared according to the formula given for Thioglycollate Medium in the 

 U.S. Pharmacopeia^ and the National Formulary.* It may be recommended as 

 a liquid medium for the cultivation of anaerobes. The suitability of Bacto-Fluid 

 Thioglycollate Medium for the sterility testing of surgical catgut sutures has been 

 reported by Clock.^ 



The advantages of a small amount of agar in liquid media used for the 

 cultivation of anaerobes has been pointed out by a number of investigators. 

 Hitchens^ demonstrated that broth containing 0.1 per cent agar was particularly 

 well suited for the growth of both aerobes and anaerobes. In such a medium 

 anaerobes grew well without any seal or other special precautions. Falk, Bucca 

 and Simmons^ pointed out the advantages of the use of small quantities of agar 

 (0.06-0.25 per cent) in the detection of contaminants in the sterility testing of 

 biologicals. 



In 1898 Trenkmann^ first reported the aerobic growth of anaerobes in the 

 presence of alkaline sulfide. Quastel and Stephenson^ reported that the presence 

 of a small amount of compound containing an -SH group permitted "aerobic" 

 growth of Clostridium sporogenes in a Tryptic Digest Broth. The -SH group 

 could be supplied by cysteine, thioglycollic acid or glutathione. 



The value of combining a small amount of agar and a reducing substance was 

 demonstrated by Brewer.^^ He showed that in a liquid medium containing 0.05 

 per cent agar, anaerobes grew equally well in the presence or absence of sodium 



