Mahboubeh Mirhosseini; Fatemeh Barzegari Firouzabadi
Abstract
Background & Objectives: Direct addition of antimicrobial materials to food during food processing is an effective method for controlling microbial contaminants of food and extending the shelf-life of food products. Objective of this research was to study the antimicrobial effect of zinc oxide (ZnO) ...
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Background & Objectives: Direct addition of antimicrobial materials to food during food processing is an effective method for controlling microbial contaminants of food and extending the shelf-life of food products. Objective of this research was to study the antimicrobial effect of zinc oxide (ZnO) nanoparticle and potential applications of ZnO nanoparticles in terms of controling two food-borne pathogens in milk. Methods: Toxicity of different concentration (0, 0.5, 2, 5, and 10 mM) of ZnO nanoparticles on Listeria monocytogenesand Bacillus cereuswas studied in culture media and milk. Results: Among the mentiond concentrations, treatment of 10 mM of ZnO nanoparticle was the most effective one for L. monocytogenesand B. cereus inhibition, which completely inhibited the growth ofL. monocytogenesand B. cereusin 24h. These data revealed concentration-dependency of the antibacterial activity of ZnO. Therefore, 5 mM and 10 mM ZnO were selected for further studies, which were performed in milk, since they demonstrated significant growth inhibition. ZnO NPs were more capable in terms of reducing the initial growth counts of all the above-stated strains in milk. Conclusion: ZnO nanoparticles had an antimicrobial activity against L. monocytogenes and B. cereusin milk and the media. This work was a preliminary study that provided a starting point for determining whether the use of ZnO nanoparticles had the potential for being applied in food preservation or not.
Mahboubeh Mirhosseini; Fatemeh Barzegari Firouzabadi
Volume 9, Issue 2 , April 2014, , Pages 99-106
Abstract
Background & Objectives: Nanotechnology is one of great important part of technology. Nanoparticles can be used in different applications for industrial, medical, military and personal use. The objectives of this study were preparation of Polystyrene/ZnO nanocomposite films via a simple method and ...
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Background & Objectives: Nanotechnology is one of great important part of technology. Nanoparticles can be used in different applications for industrial, medical, military and personal use. The objectives of this study were preparation of Polystyrene/ZnO nanocomposite films via a simple method and investigation of antibacterial activity of them.
Methods: Polystyrene /ZnO nanoparticle (PS/nano-ZnO) composite films were prepared via simple method with 0, 0.1, 1 and 2.5% wt concentration of ZnO and characterized by scanning electron microscopy (SEM). The antibacterial properties of the product were investigated against Listeria monocytogenes, Escherichia coli, Staphylococcus aureus and Bacillus cereus.
Results: The survival ratio of L. monocytogenes, E. coli, S. aureus and B. cereus decreased with increase of ZnO content on PS/nano-ZnO composite films and the best antibacterial activity was obtained with 2.5% wt ZnO-PS composite films for all bacteria. Results show the larger sensitivity of the S. aureus compared to other bacteria.
Conclusion: The treated fabric with ZnO NP indicates significant improve for antibacterial properties for polystyrene fabric.
Saeed Rezaei-Zarchi; Aisha Javed; Madiha Javeed Ghani; Safieh Soufian; Fatemeh Barzegari Firouzabadi; Abdolmajid Bayanduri Moghaddam; Seyed Hossein Mirjalili
Volume 5, Issue 2 , March 2010, , Pages 83-89
Abstract
Background: and Objectives:The aim of this study was to detect the antibacterial properties of 0.01, 0.5 and 1% nano-TiO2 and -CdO against E. coli. Materials and Methods: E. coli was cultured in liquid and agar nutrient medium to evaluate the antibacterial effects of 0.01, 0.05 and 1% of both ...
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Background: and Objectives:The aim of this study was to detect the antibacterial properties of 0.01, 0.5 and 1% nano-TiO2 and -CdO against E. coli. Materials and Methods: E. coli was cultured in liquid and agar nutrient medium to evaluate the antibacterial effects of 0.01, 0.05 and 1% of both nano-TiO2 and -CdO via the optical density (OD) and log CFU/ml measurements. Results: Non-significant effect was seen for 0.01% of both nano-specimens. While, 0.05 and 1% of both nanoparticles showed considerably decreased bacterial number. A 4.5 and 1.9 times decrease in the OD value was found in the presence of 1 and 0.5% nano-TiO2, respectively(P< 0.001). 1.5 and 3.3 times decreased OD was seen in the presence of 0.5 and 1% nano-CdO, respectively, as compared to control (P<0.001). In the second study, 6.3 log CFU/ml of E. coli were present in the cultures treated with 1% nano-TiO2 and CdO at 4 ºC in water. Control E. coli cells survived for 12 days while complete cell death was seen when 1% nano-TiO2 was applied for 13 hours as compared to 1% nano-CdO, which showed complete cell death after 15 hours. In the third study, E. coli was grown in the agar medium with and without both nanoparticles and suppressed growth (4.5 and 5.6 times; P<0.001) was seen in the presence of 1% nano-CdO and -TiO2, respectively. Conclusion: In spite of the fact that both nanoparticles showed bactericidal activity, nano-TiO2 has proven to be more efficient antibacterial agent as compared to nano-CdO.
