The objectives of this project were to develop the direct, single step fermentation of hydrolyzed gurry by propionic acid bacteria as a sole process for preservation, eliminating the need for hazardous mineral acids and for addition of organic acids and preservatives; and to study persistence and development of contaminating microorganisms at low concentrations of propionic acid during the fermentation process. Although results are based on the observations of a limited number of bacterial cultures representing various taxa, they suggest a relationship between strong fermentative metabolism and resistance to propionic acid.  Even with a 50% inoculum for establishing a rapid propionic acid fermentation of hydrolyzed cod gurry, fermentation was slow, indicating that not only is growth of the organisms slow, but that most of the propionic acid is produced after growth ceases.