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McNair Scholars Program

Keshia McAfee, M.B.A.


Education: Bachelor of Science in food science (science option) (December 2010)

Master of Business Administration from Emporia State University

McNair Project: Evaluation of Efficacy of Phosphoric Acid, Acidified Calcium Sulfate, and Boxyl Powder as Food-Grade Antimicrobials (2010)

Mentor: Randall Phebus, Ph.D.

Food safety can be enhanced through the effective use of food-grade antimicrobials. Three antimicrobials were tested in this study: phosphoric acid, acidic calcium sulfate (ACS), and Boxyl powder. The objectives of the study were to determine the minimum inhibitory concentration for each antimicrobial, and to obtain preliminary data on how each antimicrobial effects the hyperspectral images of the bacterial cells using a high resolution CytoViva® microscope. Eleven concentrations were prepared for ACS, seventeen for phosphoric acid, and twenty-one for Boxyl powder, all in tryptic soy broth (TSB). pH values were obtained for each concentration. Each concentration was inoculated with 1.0 mL of Salmonella Montevideo and Staphylococcus aureus, individually. The MIC for 4.4 N phosphoric acid for S. Montevideo was at a concentration of 2.5%, and the MBC was at a concentration of 3.5%. For S. aureus, phosphoric acid had a MIC of 3% and a MBC of 3.5%. For the ACS (10 N solution) , the MIC was determined to be 0.45%, and the MBC was 0.50% for both S. Montevideo and S. aureus. Boxyl powder had a MIC at 300 ppm, and the MBC was at 400 ppm for S. Montevideo. For tubes with S. aureus, the MIC was at 500 ppm, while the MBC was at 600 ppm. The hyperspectral images of S. Montevideo and S. aureus showed that the bacterial cells without any antimicrobial had lower maximum peak values compared with the maximum peak values of the bacterial cells from MIC and MBC.