Title page for ETD etd-08022001-104536


Type of Document Master's Thesis
Author Schurman, John Jackson
URN etd-08022001-104536
Title Antibacterial Activity of Hydrogen Peroxide Against Escherichia Coli O157:H7 and Salmonella Spp. in Fruit Juices, Both Alone and in Combination With Organic Acids
Degree Master of Science
Department Food Science and Technology
Advisory Committee
Advisor Name Title
Sumner, Susan S. Committee Chair
Eifert, Joseph D. Committee Member
Marcy, Joseph E. Committee Member
Keywords
  • Salmonella
  • Fruit Juice
  • Escherichia coli O157:H7
  • Organic Acids
  • Hydrogen Peroxide
Date of Defense 2001-07-18
Availability unrestricted
Abstract
The antibacterial efficacy of hydrogen peroxide treatments in four fruit juices was determined. Preservative free apple cider, white grape, and purple grape juice were inoculated with ~ 6.4 log CFU/ml of a five strain, acid adapted, nalidixic acid resistant E. coli O157:H7 cocktail. Orange juice was inoculated with a comparable Salmonella spp. cocktail. In the first study, 0.017% and 0.012% H2O2 was added in combination with 0.1% and 0.3% of the dominant organic acid (OA) to 4oC and 25oC juices, with samples taken each day for 21 days. H2O2 was a significant factor in all juices (p < 0.05) except white grape (lack of data), and both 0.017% H2O2 treatments reduced counts in apple cider, orange juice, and white grape to undetectable numbers within 48 hrs as cultured on tryptone soy agar + 0.05% nalidixic acid (TSAN). Treatments in purple grape juice were less effective overall, and more dependent on OA concentration (p < 0.001) than H2O2.

There were instances where bacterial survival in apple cider, purple grape, and orange juice continued for 21 days after treatment, and sometimes outlasted the control. These occurrences were dependent on temperature (25oC) and H2O2 (0.012%), but not on

OA. However, OA concentration was a significant factor (p < 0.05) overall in apple cider and purple grape juice, but not in orange juice.

In the second study, 0.015% and 0.03% H2O2 was added to 10, 25, and 40oC apple cider and orange juice inoculated with 6.4 log CFU/ml E. coli O157:H7 and Salmonella spp. respectively. Only 0.03% H2O2 was effective in reducing counts to undetectable numbers in both juices. However, both temperature and H2O2 were significant factors (p < 0.0001) in bacterial destruction, with 0.03% H2O2 at 40oC giving

undetectable numbers at < 3 and < 6 hours in orange juice and apple cider respectively.

It has been demonstrated that at ~ > 0.017%, H2O2 can provide a 5 log reduction of these pathogens in fruit juice. Increasing temperature and organic acid concentration can improve its rate of effectiveness in certain juices. However, sensory concerns may negate its use in some products.

Files
  Filename       Size       Approximate Download Time (Hours:Minutes:Seconds) 
 
 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
  JohnSchurman.pdf 341.37 Kb 00:01:34 00:00:48 00:00:42 00:00:21 00:00:01

Browse All Available ETDs by ( Author | Department )

dla home
etds imagebase journals news ereserve special collections
virgnia tech home contact dla university libraries

If you have questions or technical problems, please Contact DLA.