Combination of ultra-high pressure and xanthene -derivatives to inactivate food -borne spoilage and ...

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" Combination of ultra-high pressure and xanthene -derivatives to inactivate food -borne spoilage and pathogenic bacteria "
Joy Gail Waite A. E. Yousef

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	55457
Doc. No	:	TL25411
Call number	:	‭3286819‬
Main Entry	:	Joy Gail Waite
Title & Author	:	Combination of ultra-high pressure and xanthene -derivatives to inactivate food -borne spoilage and pathogenic bacteria\ Joy Gail Waite
College	:	The Ohio State University
Date	:	2007
Degree	:	Ph.D.
student score	:	2007
Page No	:	334
Abstract	:	Food processing methods can lead to the development of processing-resistant spoilage and pathogenic microorganisms that can cause further cost to processors and increased health risks to consumers. Thus, inactivation of these potentially problematic bacterial strains by combinations of physical and/or chemical treatments needs to be investigated. Previous studies have shown combination treatments of ultra-high pressure (UHP) with antimicrobial peptides, oxidants, and antioxidants to be efficacious at inactivating bacteria. The current study investigates the use of UHP in combination with hydroxyxanthenes, including FD&C Red No. 3, to inactivate pressure-resistant strains of Lactobacillus plantarum, Listeria monocytogenes, and Escherichia coli O157:H7. Combination treatments of UHP (400 MPa, 3 minutes) and FD&C Red No. 3 (3 to 10 ppm) resulted in significant enhancement of inactivation of several pressure-resistant Gram-positive and Gram-negative strains. FD&C Red No. 3 is a known photosensitizer and was capable of inactivating Gram-positive species with short exposure to ambient light (15-30 minutes); however this compound had no effect on Gram-negative species without UHP treatment. UHP was found to cause an irreversible change in the barrier properties of the outer membrane with pressure treatments above 250 MPa leading to accumulation of FD&C Red No. 3 correlating with cell inactivation. Inactivation of Gram-positive and Gram-negative species by combination treatment was light-dependent with low UHP treatments (<400 MPa), indicating a role of photooxidation. However, with increasing pressures (>400 MPa) a light-independent mechanism was identified for all species tested. Efficacy of light-dependent and light-independent inactivation was determined in the food systems: carrot juice and turkey meat product. Combination treatment was effective against L. monocytogenes and E. coli O157:H7 in carrot juice with FD&C Red No. 3 at concentrations of 10 to 100 ppm. These strains were resistant to inactivation by combination treatment in turkey meat product, indicating that specific food components or composition may decrease the efficacy of these treatments. Further studies were completed to determine the impact of superoxide production on the inactivation of E. coli K12 wild-type and sod mutants. Mutant strains were not significantly different in sensitivity to any of the treatments tested, however, all E. coli K12 strains were significantly more sensitive to UHP and UHP-FD&C Red No. 3 combination treatments when treated and recovered under aerobic conditions compared to anaerobic conditions. Pressure-resistant strains were treated with UHP alone and in combination with FD&C Red No. 3 under aerobic and anaerobic conditions to determine the impact of type I and type II photooxidation on inactivation. The majority of inactivation by combination treatment with light exposure is due to type I photooxidation based on little difference between aerobic and anaerobic treatments. Interestingly, inactivation without light exposure was oxygen dependent for all microorganisms tested. Further study is needed to determine if oxygen dependent effect is due to oxygen presence during treatment or during recovery. Inactivation of UHP processing-resistant microorganism can be achieved using combination treatment of UHP and FD&C Red No. 3 in food systems.
Subject	:	Biological sciences; Escherichia coli O157:H7; Food colorants; Food microbiology; Foodborne spoilage; Lactobacillus plantarum; Listeria monocytogenes; Ultrahigh pressure; Xanthene; Food science; 0359:Food science
Added Entry	:	A. E. Yousef
Added Entry	:	The Ohio State University