Date of Award:

5-1961

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Animal, Dairy, and Veterinary Sciences

Department name when degree awarded

Dairy Manufacturing

Committee Chair(s)

A. J. Morris

Committee

A. J. Morris

Committee

P. B. Larsen

Committee

R. L. Hurst

Abstract

Various temperatures and concentrations of the hydrogen peroxide catalase treatment of milk were studied in an attempt to discover the optimum temperature and concentration that would destroy unfavorable organisms and yet allow favorable ones to grow. The Federal Food and Drug Administration in their November, 1959, Definitions and Standards of Cheeses and Cheese Products states that "the amount of the hydrogen peroxide solution used shall be such that the weight of the hydrogen peroxide added thereby does not exceed 0.05 percent of the weight of the milk treated." Within the maximum level allowed, it was found that in day old manufacturing milk treated with 0.05 percent peroxide for 10 minutes at either 32 C or 49 C, more than 64 percent of all microorganisms present were destroyed. Coliform organisms were very sensitive to peroxide, exhibiting a 92 percent kill at 32 C, and a 100 percent kill at 49 C. Lactic acid producing organisms were next in sensitivity to bacterial destruction, showing an 80 and 83 percent kill respectively for the same temperatures. Spore-forming organisms showed a 42 and 73 percent kill respectively at the above temperatures, but due to the refractory nature of spores to peroxide, the difference was not significant (p .05).

In addition to the foregoing, related studies were conducted on the hydrogen peroxide treatment of milk without the addition of catalase. Storage milk was treated over night at 4 C for 16 hours with two peroxide concentrations, 0.025 and 0.05 percent. At the lower concentration the kill was not satisfactory, while at the higher concentration 50 percent of the spore-formers and 99 percent of the coliforms were killed. There was, however, a peroxide residue which would have to be eliminated to meet Federal Food and Drug Administration standards.

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