Tea leaf [Camellia sinensis (L.) Kuntze] extract-synthesized silver nanoparticles as antimicrobial agent against foodborne pathogens

Foodborne illness has emerged as an important public health problem in many countries in the last decade. The main purpose of this research is to study the antibacterial activity of silver nanoparticles against foodborne pathogens. Silver nanoparticles (AgNP) are well-known as antimicrobial agent...

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Main Author:	Loo, Yuet Ying
Format:	Thesis
Language:	English
Published:	2018
Subjects:	Foodborne diseases - Microbiology - Case studies Pathogenic bacteria Tea - Analysis
Online Access:	http://psasir.upm.edu.my/id/eprint/77086/1/FSTM%202018%2025%20IR.pdf
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id	my-upm-ir.77086
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spelling	my-upm-ir.770862020-02-11T03:16:06Z Tea leaf [Camellia sinensis (L.) Kuntze] extract-synthesized silver nanoparticles as antimicrobial agent against foodborne pathogens 2018-07 Loo, Yuet Ying Foodborne illness has emerged as an important public health problem in many countries in the last decade. The main purpose of this research is to study the antibacterial activity of silver nanoparticles against foodborne pathogens. Silver nanoparticles (AgNP) are well-known as antimicrobial agents due to their strong biocidal effect against microbial species. In this study, the synthesis of AgNP using the Chinese tea extracts from Camellia sinensis was reported. The synthesized nanoparticles were characterized using UV-vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and fourier transform infrared (FTIR) spectroscopy. The XRD analysis shows that the synthesized AgNP are of face-centered cubic structure. Well-dispersed AgNP with an approximate size of 4 nm were observed in the TEM image. The antibacterial activity of silver nanaoparticles was tested against 12 foodborne pathogens namely Escherichia coli, Escherichia coli O157:H7, Klebsiella pneumoniae, Staphylococcus aureus, Bacillus cereus, Salmonella Typhimurium, Salmonella Enteritidis, Enterococcus faecalis, Enterococcus durans, Listeria monocytogenes, Bacillus subtilissubsp. spizizenii, and Methicillin-resistant Staphylococcus aureus. The antibacterial activity of AgNPs was determined by using disc diffusion method, resazurin microtitre-plate assay (minimum inhibitory concentration, MIC), minimum bactericidal concentration test (MBC), and time-kill curve assay.The disc diffusion test showed that all the foodborne pathogens were susceptible to AgNPs. The MIC and MBC value of AgNPs against these 12 foodborne pathogens were ranged from 3.9 to 15.6μg/mL. The time kill activity of AgNPs against these foodborne pathogens was tested; the reduction in the number of CFU/ml was >3 log10 units (99.9%) in 1-2 h. This study indicates that AgNPs has antibacterial activity. The toxicity study using the brine shrimp nauplii demonstrated that AgNPs have medium toxic to A. salina (LC50 = 107.52 μg/mL). The applications of AgNPs were done by adding AgNPs into the washing-up liquid as an antibacterial additive in washing the artificially contaminated chopping board. Washing the artificially contaminated chopping board by using washing-up liquid with AgNPs reduced the bacteria count by 1.60 ± 0.11 log10 CFU/g for S. aureus; while for S. Typhimurium, the bacteria count was reduced by 2.90 ± 0.02 log10 CFU/g. The decontamination efficacy of washing using washing-up liquid with AgNPs was found to be significant (P< 0.05) and the most effective way in reducing the microbial contamination in chopping board. This is the first report to demonstratethat the application of AgNPs in washing-up liquid has significant antibacterial activity against foodborne pathogens. Overall, the findings show that AgNPs have strong antibacterial activity and can be an alternative antimicrobial agent. Foodborne diseases - Microbiology - Case studies Pathogenic bacteria Tea - Analysis 2018-07 Thesis http://psasir.upm.edu.my/id/eprint/77086/ http://psasir.upm.edu.my/id/eprint/77086/1/FSTM%202018%2025%20IR.pdf text en public doctoral Universiti Putra Malaysia Foodborne diseases - Microbiology - Case studies Pathogenic bacteria Tea - Analysis Son, Radu
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English
advisor	Son, Radu
topic	Foodborne diseases - Microbiology - Case studies Pathogenic bacteria Tea - Analysis
spellingShingle	Foodborne diseases - Microbiology - Case studies Pathogenic bacteria Tea - Analysis Loo, Yuet Ying Tea leaf [Camellia sinensis (L.) Kuntze] extract-synthesized silver nanoparticles as antimicrobial agent against foodborne pathogens
description	Foodborne illness has emerged as an important public health problem in many countries in the last decade. The main purpose of this research is to study the antibacterial activity of silver nanoparticles against foodborne pathogens. Silver nanoparticles (AgNP) are well-known as antimicrobial agents due to their strong biocidal effect against microbial species. In this study, the synthesis of AgNP using the Chinese tea extracts from Camellia sinensis was reported. The synthesized nanoparticles were characterized using UV-vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and fourier transform infrared (FTIR) spectroscopy. The XRD analysis shows that the synthesized AgNP are of face-centered cubic structure. Well-dispersed AgNP with an approximate size of 4 nm were observed in the TEM image. The antibacterial activity of silver nanaoparticles was tested against 12 foodborne pathogens namely Escherichia coli, Escherichia coli O157:H7, Klebsiella pneumoniae, Staphylococcus aureus, Bacillus cereus, Salmonella Typhimurium, Salmonella Enteritidis, Enterococcus faecalis, Enterococcus durans, Listeria monocytogenes, Bacillus subtilissubsp. spizizenii, and Methicillin-resistant Staphylococcus aureus. The antibacterial activity of AgNPs was determined by using disc diffusion method, resazurin microtitre-plate assay (minimum inhibitory concentration, MIC), minimum bactericidal concentration test (MBC), and time-kill curve assay.The disc diffusion test showed that all the foodborne pathogens were susceptible to AgNPs. The MIC and MBC value of AgNPs against these 12 foodborne pathogens were ranged from 3.9 to 15.6μg/mL. The time kill activity of AgNPs against these foodborne pathogens was tested; the reduction in the number of CFU/ml was >3 log10 units (99.9%) in 1-2 h. This study indicates that AgNPs has antibacterial activity. The toxicity study using the brine shrimp nauplii demonstrated that AgNPs have medium toxic to A. salina (LC50 = 107.52 μg/mL). The applications of AgNPs were done by adding AgNPs into the washing-up liquid as an antibacterial additive in washing the artificially contaminated chopping board. Washing the artificially contaminated chopping board by using washing-up liquid with AgNPs reduced the bacteria count by 1.60 ± 0.11 log10 CFU/g for S. aureus; while for S. Typhimurium, the bacteria count was reduced by 2.90 ± 0.02 log10 CFU/g. The decontamination efficacy of washing using washing-up liquid with AgNPs was found to be significant (P< 0.05) and the most effective way in reducing the microbial contamination in chopping board. This is the first report to demonstratethat the application of AgNPs in washing-up liquid has significant antibacterial activity against foodborne pathogens. Overall, the findings show that AgNPs have strong antibacterial activity and can be an alternative antimicrobial agent.
format	Thesis
qualification_level	Doctorate
author	Loo, Yuet Ying
author_facet	Loo, Yuet Ying
author_sort	Loo, Yuet Ying
title	Tea leaf [Camellia sinensis (L.) Kuntze] extract-synthesized silver nanoparticles as antimicrobial agent against foodborne pathogens
title_short	Tea leaf [Camellia sinensis (L.) Kuntze] extract-synthesized silver nanoparticles as antimicrobial agent against foodborne pathogens
title_full	Tea leaf [Camellia sinensis (L.) Kuntze] extract-synthesized silver nanoparticles as antimicrobial agent against foodborne pathogens
title_fullStr	Tea leaf [Camellia sinensis (L.) Kuntze] extract-synthesized silver nanoparticles as antimicrobial agent against foodborne pathogens
title_full_unstemmed	Tea leaf [Camellia sinensis (L.) Kuntze] extract-synthesized silver nanoparticles as antimicrobial agent against foodborne pathogens
title_sort	tea leaf [camellia sinensis (l.) kuntze] extract-synthesized silver nanoparticles as antimicrobial agent against foodborne pathogens
granting_institution	Universiti Putra Malaysia
publishDate	2018
url	http://psasir.upm.edu.my/id/eprint/77086/1/FSTM%202018%2025%20IR.pdf
_version_	1747813203297959936

Tea leaf [Camellia sinensis (L.) Kuntze] extract-synthesized silver nanoparticles as antimicrobial agent against foodborne pathogens

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