Date of Award

5-2005

Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Food Science and Human Nutrition

Advisor

Alfred A. Bushway

Second Committee Member

Rodney Bushway

Third Committee Member

Mahmoud El-Begearmi

Abstract

Escherichia coli 01 57:H7 is a human pathogen that is a concern for children, elderly, and people with weakened immune systems. A number of food-borne outbreaks caused by E. coli 0157:H7 have been from the consumption of contaminated ground beef that was not cooked to the correct internal temperature. Natural compounds have been investigated to determine antimicrobial potential. Blueberries contain antimicrobial compounds, anthocyanins and phenolic acids, that could potentially decrease E. coli 0 1 57:H7 in ground beef. Five experiments were conducted to determine if blueberry juice concentrate, powder and essence in sterile distilled water (37°C)(1,2.5, 5.0, and 10.0%), Brain Heart Infusion broth (37 and 3S°C)(1, 2.5,5.0, and 10.0%), raw ground beef (3S°C) (blueberry powder and concentrate at 5.0, 10.0, and 15.0%) and cooked ground beef (3S°C)(5.0% blueberry powder and 5.0 and 10.0% blueberry concentrate) possess antimicrobial properties against E. coli 01 57:H7.

Overall, the higher the blueberry juice concentrate and powder the greater the reduction of E. coli 0157:H7 in sterile water, Brain Heart Infusion (BM) broth and raw ground beef at both 37 and 3.5°C. There were significant differences (p < 0.05) in E. coli 0157:H7 for all the high concentrations (10% for sterile water and BHI broth; 15% for raw ground beef) of blueberry products in each study except the cooked ground beef. There were no significant differences (p < 0.05) in E. coli 01 57:H7 between the blueberry juice concentrate and powder. There were no effects with blueberry essence, and no large reduction in E. coli 0 1 57:H7 in blueberry treated cooked ground beef. The combined effect of pH and antimicrobial compounds present in blueberry juice concentrate and powder has the potential to decrease E. coli 0157:H7.

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