Date of Award:

5-1-1973

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biology

Department name when degree awarded

Bacteriology and Public Health

Committee Chair(s)

F. J. Post

Committee

F. J. Post

Committee

P. B. Carter

Committee

D. K. Salunkhe

Abstract

The requirement of bacteria for water increases when temperature of growth deviates from the organism's optimum growth temperature. A psychrophilic organism was isolated from a meat sample stored at refrigerator temperature and shown to have an optimum temperature 17 C. Partial identification of the unknown meat isolate was also carried out using morphological and biochemical characteristics. A comparative study was carried out using a mesophile Staphylococcus aureus and a thermophile Bacillus stearothermophillus for requirements of free water at different temperature ranges. The organisms were grown in media of varying salt concentration at a wide range of growth temperatures (the meat isolate at 5 C to 25 C; S. aureus at 26. 5 C to 42. 5 C; and B. stearothermophilus at 47. 5 C to 63. 5 C). It was observed that all the organisms tested tolerated the highest salt concentration (lowest water activity) at their optimum growth temperature, and as the temperature deviated tolerance decreased.

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