Date of Award


Degree Type

Bachelors Essay

Degree Name

Bachelor of Science (BS)



First Advisor

John R. Koch

Second Advisor

Virgil Roach


The writer, having been employed in the dry yeast research laboratory of one of this country's largest yeast concerns for the past three years, is very much interested in those factors which might affect the qualities of the final dry yeast product, and has therefore made the investigations presented in this paper.

Because of the numerous pieces of metallic equipment employed in the production of yeast, the possibility of metallic contamination in the final yeast product is considerable. Thus, the investigation presented in this paper was carried out in an effort to determine just what effect various concentrations of various metals have on the activity of dry yeast. The metals used in this investigation were chosen because they are the most common ones by which the equipment employed in the fermentation process might introduce metallic contamination.


A Thesis Submitted to the Faculty of the College of Liberal Arts Marquette University in Partial Fulfillment of the Requirements for the Degree of Bachelor of Science

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