UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 819 



J\2£*^L 



Contribution from the Bureau of Chemistry 

 CARL L. ALSBERG, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



March 10, 1920 



A PINK YEAST CAUSING SPOILAGE IN OYSTERS 



By Albert C. Hunter, 1 Junior Bacteriologist, Microbiological Laboratory* 



CONTENTS. 



Page. 



Purpose of investigation 1 



Historical review 2 



Distribution of the pink yeast 3 



In and about the oyster house- 4 



In oysters 5 



In water 7 



In mud 9 



Experimental production of pink 



color in oysters 10 



Morphology of the pink yeast 11 



Page. 



Cultural features of the pink yeast- 11 

 Biochemical features of the pink 



yeast 12 



Physical features of the pink yeast- 16 

 Resistance of the pink yeast to dis- 

 infectants 20 



Discussion of results 21 



Summary 23 



Bibliography 24 



PURPOSE OF INVESTIGATION. 



At certain periods during the last few years the oyster growers of 

 New England have had difficulty in shipping oysters for long dis- 

 tances without the development of a pink color in the liquor or on 

 the oyster itself. Analyses of shipments showing this color have 

 demonstrated the cause. The organism producing the pink pigment 

 is a yeast-like fungus which grows readily at low temperature, and 

 produces pigment bright enough to be noticed only when the ship- 

 ment has been in transit three or four days. Oysters which appear 

 to be in good condition when shipped are often found to be pink 

 when they reach their destination. 



1 The major portion of this investigation was carried on at Brown University, Provi- 

 dence, R. I., under the supervision of Prof. F. P. Gorham, and was submitted to the 

 faculty of that institution in partial fulfillment of the requirements for the degree of 

 doctor of philosophy. During the early part of the investigation valuable assistance was 

 given the writer by Charles W. Parmelee. The work was completed and the report re- 

 vised in the Microbiological Laboratory of the Bureau of Chemistry. Valuable criticisms 

 and suggestions have been offered by Dr. Charles Thorn of that laboratory. 

 140536°— 20— Bull. 819 1 



