346 BIOLOGICAL ACTIVITIES OF YEASTS 



tion of these substances, as well as dairy products, make them read- 

 ily subject to decomposition by yeasts. 



However, other substances which one would not expect to be 

 spoiled by yeasts are also attacked. Some yeasts are capable o^ 

 growing in strong pickle brines, sauerkraut, and even on salted fish. 

 Species of Rhodotorula may produce pink or red discolorations in 

 fats of both vegetable and animal origin and in sauerkraut. Under 

 certain conditions, certain strains of "Saccharomyces ellipsoideus" 

 are said to develop a pink pigment. According to Jensen ^^ the 

 lipophilic *S. pulcherrimus of Beijerinck (see page 287) produces a 

 red pigment in the presence of soluble iron salts. Yeasts of the 

 Candida and Rhodotorula genera have been found to be factors in 

 the spoilage of beef. These organisms are capable of proliferating 

 at temperatures close to — 1° C. where chilled beef is stored. Oc- 

 casionally, the slimes on sausages have been found to be due to 

 yeasts. 



No attempt has been made here to catalog the various genera of 

 yeasts that have been reported in foodstuffs. For further details and 

 procedures the reader is referred to Tanner's Microbiology of Foods^^ 

 The method of examining food for yeasts may be found in the 

 Official and Tentative Methods of Analysis of the Association of 

 Official Agricultural Chemists.^ 



LITERATURE 



1. Anderson, H. W., Yeast-like fungi of the human intestinal tract, J. Infec- 



tious Diseases, 21, 341 (1917). 



2. Association of Official Agricultural Chemists. Official and Tentative 



Methods of Analysis of the Association of Official Agricultural Chemists, 

 Washington, D. C, 6th ed., 1945. 



3. Atkin, L., a. S. Schultz, and C. N. Frey, Ultramicrodetermination of thi- 



amine by the fermentation method, J. Biol. Chem., 129, 471 (1939). 



4. Atkin, L., A. S. Schultz, W. L. Williams, and C. N. Frey, Yeast micro- 



biological methods for determination of vitamins, Ind. Eng. Chem., Anal. 

 Ed., 15, 141 (1943) ; 16, 67 (1944). 



5. Ball, E. G., Chemical reactions of nicotinic acid amide in vivo, Bull. Johns 



Hopkins Hosp., 65, 253 (1939). , 



6. Bergius, F., Conversion of wood to carbohydrates, Ind. Eng. Chem., 29, 



247 (1937). 



7. Bilford, H. R., R. E. Scalp, W. H. Stark, and P. J. Kolachov, Alcoholic 



fermentation of molasses, Ind. Eng. Chem., 34, 1406 (1942). 



8. Boulard, H., Societe d' exploitation des precedes, H. Boulard, 1931 (cited 



by Prescott ^s). 



9. BuRK, D., A colloquial consideration of the Pasteur and neo-Pasteur effects. 



Symposia on Qv/intitative Biology, VII, 420 (1939). 



