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Mariam Surour Al Shamsi
Department of Food Science
College of Food and Agriculture
Dissertation
Title
Biofilm Production by Food-Transmitted Bacteria and the Use of Selected Nanoparticles to
Control their Biofilm Production
Faculty Advisor
Dr. Aisha Abushelaibi
Defense Date
26 May 2015
Abstract
Biofilm is a population of bacteria attached to any types of surfaces and impeded in a self-produced matrix of
extracellular polymeric substances. Biofilm exhibit up to 1000 fold antibiotic increased resistance to a broad range
of antimicrobial agents. Several food-transmitted microorganisms are capable of forming biofilms and considered
as a major source of contamination, transmission and infection. In the last few decades, nanoparticles has gained
a great attention for their potential applications as antimicrobial agents. The aim of this work was to assess the
biofilm formation capacity of food-transmitted bacteria under various environmental conditions and to investigate
the efficacy of different nanoparticles (i.e. Ag-Cu-B, Ag-Na-B, and Ag-Cu-B) to kill microbial pathogens in biofilms.
Nanoparticles were synthesized by using co-precipitation and microwave techniques and characterized for their
physiochemical properties by transmission electron microscopy and light dynamic scattering. The antibiofilm and
antimicrobial properties of the synthesized nanoparticles were investigated using S. aureus (10 strains), P. aeruginosa
and E. coli (3strains). The findings revealed that all NPs significantly inhibited planktonic cells and biomass of the grown
biofilms. Moreover, the sanitization efficacy of nanoparticles were assessed on stainless steel surface that commonly
come into contact with food. The surfaces were inoculated with strains of S. aureus and Salmonella and cleaned with
NPs saturated sanitary wipes. A significant reduction was observed in viability of the cells on the stainless steel surfaces.
The results demonstrated that the use of NPs incorporated into sanitary wipes is useful method to eliminate bacteria
on food contact surfaces.
Research Relevance and Potential Impact
In recent years, the development of new technology such as nanotechnology has gained the attention of the scientific community. However,
the application of nanotechnology in the food systems is still in infancy. It is well known that metallic nanoparticles have anti-microbial effects
and have been used as external sanitizers, disinfectants and in non-food applications. In the meantime, food safety has become a global issue
due to continuously and repeatably of outbreaks of foodborne pathogens such as Listeria mon-ocytogenes, Salmonella sp. and E. coli O157:H7.
Relevant Publications
Abushelaibi, A. A.,
Mariam. S. Alshamsi, Hanan Afifi. Use of antimicrobial agent in food processing systems. Resent patent in Food, nutrition and
agriculture. April 2012. 4 (1)2-7.
Career Aspirations
Highly motivated, research and development manager at Abu Dhabi Quality and Conformity Council. My career mission is
to develop into an outstanding person in my work and to use my technical skills to direct and utilize research to deliver
benefits for the community and support the development of evidence based innovative practices.