86 DIFGOMANUAL 



Scientific Research and Development. It is recommended for use as a general 

 culture medium for both aerobic and anaerobic bacteria. It has proved especially 

 valuable as a primary medium for culturing pathological specimens and as a 

 stock culture medium on which to carry most laboratory cultures. This medium, 

 containing solid meat particles, has the unusual capacity for initiating growth 

 of bacteria from minute inocula and for maintaining the viability of cultures 

 over long periods of time. 



Theobald Smith^ first made use of fresh unheated animal tissue for cultivating 

 anaerobic organisms. Tarozzi^ confirmed Smith's findings on the value of un- 

 heated tissue in broths for anaerobic culture, and discovered further that he 

 could heat the meat-broth to 104-1 05 °C. for 15 minutes without destroying its 

 capacity to support anaerobic growth, A steam sterilized emulsion of brain tissue 

 in water was employed by von Hibler^'* for cultivating anaerobic bacilli, and 

 found to be particularly valuable in culturing and classifying these organisms. 

 It was further noted by von Hibler that organisms growing in the cooked brain 

 mash were less susceptible to the harmful effects of toxic metabolic products 

 than were those cultured in milk or carbohydrate serum media. Robertson^ care- 

 fully analyzed von Hibler's results and substituted beef heart for the brain tissue. 

 She found the Cooked Meat Medium to be equally as satisfactory as the Cooked 

 Brain Medium. Henry^ employed the Cooked Meat Medium successfully for 

 culturing the anaerobes and recommended it for differentiating between various 

 putrefactive and saccharolytic species. Holman'^ used Cooked Meat Medium for 

 general culture purposes and commented: "Perhaps the most favorable charac- 

 teristic of the medium, after its general growth stimulating influence, is that the 

 products of growth do not rapidly destroy the various forms, and of all media in 

 common use it is to the meat medium that one can constantly return to reisolate 

 bacteria which have died out or have become hopelessly overgrown in other 

 media. The meat is the best single medium we have for studying the anaerobes 

 from war wounds, the reactions are useful for rapid differentiation of groups, as 

 well as for individual identification, and no other medium we have can so readily 

 indicate the presence of anaerobes in mixed cultures where they are often not 

 expected. The cooked meat medium is the most useful medium we have at pres- 

 ent for obtaining growth of both anaerobic and aerobic bacteria, for storing 

 mixed cultures for later isolation, as well as pure cultures for further investi- 

 gation. "Standard Methods for the Examination of Dairy Products"^ specifies the 

 use of Holman's Alkaline Cooked Meat Medium for use in the examination of 

 frozen dessert ingredients and "Diagnostic Procedures and Reagents"^ describes 

 a Ground Meat Medium for the cultivation of anaerobes. 



The capacity of Cooked Meat Medium to initiate growth of minute inocula of 

 both aerobic and anaerobic microorganisms makes it especially valuable for use 

 in the primary culture of clinical specimens wherein the causative agent may be 

 present in such small numbers that enrichment is necessary. In such primary 

 cultures, even though more than one organism be present, the slower growing 

 organisms continue to proliferate without great danger of overgrowth by the 

 faster growing organisms, as is true in case of many other culture media. 



Bacto-Cooked Meat Medium is also an excellent stock culture medium in 

 which to carry laboratory cultures of most microorganisms. Experience indicates 

 that in this medium strains of the Clostridia, such as tetani, novyi, septicum, 

 botulinum, sporogenes, putrificum, bijermentans, perfringens, and histolyticum 

 have remained viable as long as ten years. The Gram-negative enteric bacteria, 

 including Shigella, Salmonella, Proteus, and the coliforms, all remained viable 

 for more than five years; staphylococci, Corynebacteria and Lactobacilli have 

 persisted for more than six months. 



To rehydrate the medium, suspend 12.5 grams of Bacto-Cooked Meat 



