scholarly journals The Effectiveness of Nanocomposite Films Against Gram-Positive and Gram-Negative Foodborne Pathogenic Bacteria

Author(s):  
Khaled Saif-Aldin ◽  
Sahar Al-Hariri ◽  
Adnan Nizam ◽  
Obaida Alhajali

In this research, nanocomposites consisting of a mixture of linear low-density polyethylene polymer (LLDPE) and zinc oxide nanoparticles (ZnO-NPs) were prepared. The films of the composite material were formed with five weight ratios (0.25, 0.5, 1, 2.5, and 5wt%) in addition to pure LLDPE, intended to investigate the role of nanomaterials in improving the performance of some properties of LLDPE polymer such as increasing the shelf life of food products and protecting the consumer from pathogenic germs in food packaging applications. The efficacy was evaluated against pathogenic bacteria, Escherichia coli and Staphylococcus aureus, through the standard "ISO 22196". The test results confirm that the nanocomposite films containing 0.5wt% or more of nano-zinc oxide have bacteriostatic activity. This activity increases with the increase of ZnO-NPs in the LLDPE polymeric phase, and the highest antibacterial effect was in the nanocomposite films of 5wt%. It was found that gram-positive bacteria were more sensitive to ZnO-NPs than gram-negative bacteria and that these nanocomposite films can provide a safe way to preserve food without the need for food processing.

2022 ◽  
Vol 12 (2) ◽  
pp. 710
Author(s):  
Fohad Mabood Husain ◽  
Faizan Abul Qais ◽  
Iqbal Ahmad ◽  
Mohammed Jamal Hakeem ◽  
Mohammad Hassan Baig ◽  
...  

Global emergence and persistence of the multidrug-resistant microbes have created a new problem for management of diseases associated with infections. The development of antimicrobial resistance is mainly due to the sub-judicious and unprescribed used of antimicrobials both in healthcare and the environment. Biofilms are important due to their role in microbial infections and hence are considered a novel target in discovery of new antibacterial or antibiofilm agents. In this article, zinc oxide nanoparticles (ZnO-NPs) were prepared using extract of Plumbago zeylanica. ZnO-NPs were characterized and then their antibiofilm activity was tested against Gram-positive and Gram-negative bacteria. The ZnO-NPs were polydispersed, and the average size was obtained as 24.62 nm. The presence of many functional groups indicated that phytocompounds of P. zeylanica were responsible for the synthesis, capping, and stabilization of ZnO-NPs. Synthesized NPs inhibited the biofilm formation of E. coli, S. aureus, and P. aeruginosa by 62.80%, 71.57%, and 77.69%, respectively. Likewise, concentration-dependent inhibition of the EPS production was recorded in all test bacteria. Microscopic examination of the biofilms revealed that ZnO-NPs reduced the bacterial colonization on solid support and altered the architecture of the biofilms. ZnO-NPs also remarkably eradicated the preformed biofilms of the test bacteria up to 52.69%, 59.79%, and 67.22% recorded for E. coli, S. aureus, P. aeruginosa, respectively. The findings reveal the ability of green synthesized zinc oxide nanoparticles to inhibit, as well as eradicate, the biofilms of Gram-positive and Gram-negative bacteria.


Foods ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1143 ◽  
Author(s):  
Santosh Kumar ◽  
Abhinab Mudai ◽  
Barnali Roy ◽  
Indra Bhusan Basumatary ◽  
Avik Mukherjee ◽  
...  

In the context of emerging global concerns with synthetic plastic packaging, alternative natural biodegradable packaging materials are gaining increasing attention for food packaging applications. In this study, chitosan and gelatin nanocomposite hybrid films containing green synthesized zinc oxide (ZnO) nanoparticles (NPs) were developed and microstructural properties were studied. Antimicrobial activity of the developed films was evaluated using both Gram negative (Escherichia coli) and Gram positive bacteria (Staphylococcus aureus). Green synthesis protocol was used for the precipitation of ZnO NPs using fruit extract of Cassia fistula. The as-synthesized polyhedral ZnO NPs were in the range of 20–40 nm (average size ≈29 nm). Reinforcement with ZnO NPs in the hybrid films lead to improved thermal stability, elongation-at-break (EAB), and compactness properties. The developed films with 2% and 4% ZnO NPs showed a smooth, compact, and heterogeneous surface morphology compared to the control (chitosan-gelatin hybrid) films. Disc diffusion assays showed that the nanocomposite film had significant antimicrobial activity against E. coli. The developed hybrid nanocomposite films have potential to be developed as biodegradable alternative for postharvest packaging of fresh fruits and vegetables.


2021 ◽  
Author(s):  
Leila Tabande ◽  
Mozhgan Sepehri ◽  
Jafar Yasrebi ◽  
Mehdi Zarei ◽  
Reza Ghasemi-Fasaei ◽  
...  

Abstract Zinc oxide nanoparticles (ZnO-NPs) are among the most commonly used nano-fertilizers (NF). However, elevated levels of ZnO-NPs in soil may affect plant growth and development due to its potential toxicity when accumulated in large amounts in plant tissues. This research was conducted using an in situ rhizobox system with the aims of evaluating Zinc uptake from nano-zinc oxide amended rhizosphere soil by alfalfa plant and the effect of plant growth promoting microorganisms on alleviating the phytotoxicity of ZnO-NPs. Treatments included microbial inoculations (Sinorhizobium meliloti, Serendipita indica) and different ZnO-NPs concentrations (0, 400 and 800 mg Kg− 1) with three replications. The results indicated that S. indica minimized the phytotoxicity of ZnO-NPs to alfalfa by enhancing growth rate and decreasing Zinc (Zn) translocation from root to shoot. Compared with plants inoculated with S. meliloti, co-inoculation with S. indica increased the shoot dry weight by 18.33% and 8.05% at 400 and 800 mg Kg− 1ZnO-NPs. However, at the highest level of ZnO-NPs (800 mg kg− 1), root inoculation of S. indica and S. indica + S. meliloti decreased Zn transfer factor by 60.2% and 44.3% compared to S. meliloti, respectively. Furthermore, a distinct relation between tolerance of S. indica-colonized plant to ZnO-NPs and the ability of S. indica in inhibiting or retarding degradation of polyunsaturated lipids through prevention of excess reactive oxygen species formation was observed. Malondialdehyde content of inoculated plants with S. indica either alone or in combination with S. meliloti was significantly lower than non-inoculated plants (p < 0.01). Zn-induced oxidative stress was mitigated by S. indica through enhanced activities of catalase and peroxidase enzymes. The findings of the present study indicate the potential use of endophytes fungus S. indica for ensuring food safety and security, and human health in heavy metal–polluted soil by reducing the phytoavailability of heavy metals in the aerial parts of the host plants.


2014 ◽  
Vol 8 (3) ◽  
pp. 40-45
Author(s):  
Zina Hashem Shehab ◽  
Huda Suhail Abid ◽  
Sumaya Fadhil Hamad ◽  
Sara Haitham

The study was conducted to evaluate the inhibitory activity of methanol extract of Gardenia jasminoides leaves compared with leaf crude extracts for some organic solvents namely Methanol, Ethanol, Petroleum ether, Asetone and Chloroform on growth of some pathogenic bacteria and yeast, which included four gram positive isolates Staphylococcus aureus, Enterococcus faecalis, Streptococcus pyogenes and Bacillus cereus and gram negative isolates Escherichia coli, Salmonella typhi, Proteus vulgaris and Pseudomonas aeruginosa and some yeasts Candida albicans and Saccharomyces boulardii, by using well diffusion method. The inhibitory activity of extracts in the tested bacterial strains and yeasts was varied according to the type of extracting solvents and are tested microorganisms. The methanol callus extract which grown on Murashige and Skoog (MS) media by using (Naphthalen acitic acid) NAA and (Benzyle adenine) BA as growth regulator highly effective as compared to the other extracts as for inhibition of three gram positive bacteria and three gram negative bacteria,which include Staphylococcus aureus and, Proteus vulgaris, followed by acetone and ethanolic extracts which include two gram positive bacteria and two gram negative bacteria. All extracts had highly effect in growth of Candida albicans while all crude extracts didn’t show any sensitivity against Saccharomyces boulardii, and when we’d done (High Performance Liquid Chromatography) HPLC test for detection of some active compound we found Quinic acid, Iridiods glycosides and Crocin which its rate in fresh callus was higher than fresh leaves.


2011 ◽  
Vol 60 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Svetlana A. Ermolaeva ◽  
Alexander F. Varfolomeev ◽  
Marina Yu. Chernukha ◽  
Dmitry S. Yurov ◽  
Mikhail M. Vasiliev ◽  
...  

Non-thermal (low-temperature) physical plasma is under intensive study as an alternative approach to control superficial wound and skin infections when the effectiveness of chemical agents is weak due to natural pathogen or biofilm resistance. The purpose of this study was to test the individual susceptibility of pathogenic bacteria to non-thermal argon plasma and to measure the effectiveness of plasma treatments against bacteria in biofilms and on wound surfaces. Overall, Gram-negative bacteria were more susceptible to plasma treatment than Gram-positive bacteria. For the Gram-negative bacteria Pseudomonas aeruginosa, Burkholderia cenocepacia and Escherichia coli, there were no survivors among the initial 105 c.f.u. after a 5 min plasma treatment. The susceptibility of Gram-positive bacteria was species- and strain-specific. Streptococcus pyogenes was the most resistant with 17 % survival of the initial 105 c.f.u. after a 5 min plasma treatment. Staphylococcus aureus had a strain-dependent resistance with 0 and 10 % survival from 105 c.f.u. of the Sa 78 and ATCC 6538 strains, respectively. Staphylococcus epidermidis and Enterococcus faecium had medium resistance. Non-ionized argon gas was not bactericidal. Biofilms partly protected bacteria, with the efficiency of protection dependent on biofilm thickness. Bacteria in deeper biofilm layers survived better after the plasma treatment. A rat model of a superficial slash wound infected with P. aeruginosa and the plasma-sensitive Staphylococcus aureus strain Sa 78 was used to assess the efficiency of argon plasma treatment. A 10 min treatment significantly reduced bacterial loads on the wound surface. A 5-day course of daily plasma treatments eliminated P. aeruginosa from the plasma-treated animals 2 days earlier than from the control ones. A statistically significant increase in the rate of wound closure was observed in plasma-treated animals after the third day of the course. Wound healing in plasma-treated animals slowed down after the course had been completed. Overall, the results show considerable potential for non-thermal argon plasma in eliminating pathogenic bacteria from biofilms and wound surfaces.


1914 ◽  
Vol 19 (5) ◽  
pp. 501-512 ◽  
Author(s):  
Charles Krumwiede ◽  
Josephine S. Pratt

Several green dyes show a marked selective action for members of the typhoid-paratyphoid-colon group. This can be used for the enrichment of typhoid and paratyphoid bacilli present in feces. Forty dyes were tested with thirty strains covering all types of pathogenic bacteria. In general the dyes restrained the growth of the Gram-positive bacteria but had no effect on the growth of the Gram-negative group.


2018 ◽  
Vol 29 ◽  
pp. 70-77 ◽  
Author(s):  
Anjana Devkota ◽  
Ritu Kumari Das

Antibacterial activities of Xanthium strumarium L. (Asteraceae) was carried out in laboratory. Distilled water and methanol extracts of the leaves of plant was prepared. The antibacterial activity was studied against six pathogenic bacteria, three gram negative: Klebsiella pneumoniae (ATCC 15380), Proteus mirabilis (ATCC 49132), Escherichia coli (ATCC 25922) and three gram positive: Bacillus subtilis (ATCC 6633), Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 25932) at different concentrations (50 mg/ml, 100 mg/ml, 150 mg/ml, 200 mg/ ml, 250 mg/ml) of leaf extracts of X. strumurium. The phytochemical screening depicted the presence of terpenoids, saponins, flavonoids, tannins and alkaloids. The antibacterial activity of extracts was determined by disc diffusion method and zone of inhibition (ZOI) was measured. Gram negative bacteria was found more resistant than gram positive bacteria. The most susceptible bacterium was S. aureus while the most resistant bacterium was E. coli. Methanolic extract was found more effective than distilled water. These findings suggest that extracts obtained from leaves of X. strumurium possess biobactericidal potential, which can suitably be exploited for making antibacterial drugs.J. Nat. Hist. Mus. Vol. 29, 2015, Page: 70-77


2021 ◽  
Vol 12 (2) ◽  
pp. 1824-1834

Secondary metabolites from the shoots and roots of three Rumex species collected from three different habitats were investigated (Rumex dentatus collected from cultivated land, R. pictus collected from the coastal desert and R. vesicarius collected from the inland desert) and tested for antioxidant activity as well as for anti-microbial activity against some human pathogenic bacteria. The present study indicated that the quantitative analysis of shoot and root extracts of three Rumex spp. were found to be rich in tannins and phenolics composition. The aerial parts of the three plants exhibited the highest significant values compared to the root parts. The MeOH extracts of Rumex species showed adequate antioxidant activity, wherein the IC50 values of the MeOH from the cultivated sample was 41.61 and 31.31 mg mL-1, coastal samples were 34.99 and 23.99 mg mL-1, while the sample of inland showed IC50 value of 41.59 and 31.67 mg mL-1, for root and shoot, respectively. Furthermore, using a filter paper disc assay, the MeOH extracts of the three Rumex species showed a substantial anti-microbial inhibitory effect on the growth of 10 pathogenic bacteria. According to sensitivity, the tested organisms could be sequenced as following: E. coli < K. pneumoniae ˂ S. typhi < P. aeruginosa for Gram-negative bacteria and B. subtilis < S. pneumoniae ˂ L. monocytoyenes < S. epidermis < S. aureus < B. cereus for Gram-positive bacteria. In addition, the antibacterial performance of R. dentatus root and R. vesicarius shoot MeOH extract is 100% broad spectrum against Gram-negative bacteria. A shoot of R. dentatus and R. pictus MeOH extract against Gram-positive bacteria is 83.3% broad spectrum. A further study is recommended for more characterization of the major compounds and assesses their efficiency and biosafety.


Heritage ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 2481-2493
Author(s):  
Sahar Ismael ◽  
Ali Omar ◽  
Manal Maher

Mummies in museums are exposed to different deterioration factors like microorganisms, especially unwrapped mummies, such as the screaming mummy. This screaming mummy in the store of the Egyptian museum is suffering from stains due to microbial infection. There are three trends of materials to inhibit microbial growth: nano materials, plant extraction and chemical materials. This research compares three materials representing the three trends such as nano zinc oxide (ZnO-NPs), Ceratophyllum demersum and 4-chloro-m-cresol, respectively. Microorganisms, isolated from the degraded mummy, were identified with an optical microscope and ribosomal ribonucleic acid (rRNA) analysis to guarantee identification accuracy. Results indicated that the bacteria in the mummy are Bacillus jeotgali, Kocuria turfanensis, Microbacterium imperial, Micrococcus luteus and Bacillus megaterium. Fungi are Monascus pallens and Rhizopus oryzae. The results of minimum inhibitory concentration (MIC) illustrated that the best concentrations for the bio treatment of isolated microorganisms is plant extract (Ceratophyllum demersum) at 600 ppm/100 mL, followed by 4-chloro-m-cresol at 600 ppm/100 mL and finally nano zinc oxide at 700 ppm/100 mL.


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