scholarly journals Effective microbial disinfection in food industry with hydroxyl radical fumigation

Food Research ◽  
2020 ◽  
Vol 4 (S4) ◽  
pp. 65-72
Author(s):  
W. Sangadkit ◽  
J. Kongtrub
Keyword(s):  
Hydrogen Peroxide ◽  
Hydroxyl Radicals ◽  
Food Industry ◽  
Microbial Inactivation ◽  
Oxidizing Agent ◽  
Surface Disinfection ◽  
E Coli ◽  
Healthcare Settings ◽  
Micron Size ◽  
Uv C

Hydrogen peroxide (H2O2) fumigation has recently been explored and tested to be a good fumigant replacement of formaldehyde. This technique has been proven safer, less irritating and requires shorter exposure times. Surface disinfection has long been implemented with toxic formaldehyde or 35% hydrogen peroxide (H2 O2 ). The results showed that they could be replaced with a safer and stronger oxidizing agent, activated H2O2 in a vaporized form. Aerosolization by aerosol generators has been used to produce aerosols containing hydroxyl radicals of hydrogen peroxide. The dispersal of this highly oxidizing mist of micron-size droplets destroyed Escherichia coli and Aspergillus niger colonies that have been artificially spiked on surfaces. The experiments demonstrated efficient disinfection by integrating 1 to 5% H2 O2 fumigation with ozone (O3 ) and ultraviolet light (UV-C). Studies with E. coli and A. niger showed some disinfection with either O3 or UV-C. Combining H2 O2 fumigation with both O3 and UV-C exposure considerably accelerated the microbial inactivation. This approach allowed fast disinfection with 1 to 5% H2 O2 while offering cheaper and safer disinfection for healthcare settings.

scholarly journals ALTERNATIVE UV LIGHT SOURCES FOR SURFACE DISINFECTION

2021 ◽  
Vol 1 ◽  
pp. 218-222
Author(s):  
Atis Skudra ◽  
Linda Mezule ◽  
Karina Spunde ◽  
Gita Revalde ◽  
Anna Zajakina ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Contact Time ◽  
Uv Light ◽  
Microbial Inactivation ◽  
Light Sources ◽  
The Novel ◽  
Surface Disinfection ◽  
E Coli ◽  
Uv C ◽  
Harmful Effects

Mercury UV-C light sources are long known to be efficient for microbial inactivation and have been widely used. At the same time, the radiation, if used in inappropriate doses and spectral regimes, can also cause harmful effects to human tissue. The aim of the study was to evaluate the applicability of the novel UV light sources from thallium – antimony at different UV-C. For the research specially made light sources were produced. The influence of UV-C radiation in the range of 200 - 280 nm was tested on Gramnegative bacterium Escherichia coli, both with mercury and thallium. More than 99.99 % inactivation of E. coli cells was obtained after 10 min contact time for thallium – antimony UV-C light source, demonstrating the potential of the produced lamps.

Reuse of Homogeneous Fenton’s Sludge from Detergent Industry as Fenton’s Catalyst

2013 ◽  
Vol 16 (2) ◽  
Author(s):  
André F. Rossi ◽  
Rui C. Martins ◽  
Rosa M. Quinta-Ferreira
Keyword(s):  
Hydrogen Peroxide ◽  
Hydroxyl Radicals ◽  
Heterogeneous Catalysts ◽  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
Iron Catalyst ◽  
Advanced Oxidation ◽  
Detergent Industry ◽  
Oxidizing Agent ◽  
Fenton’S Reaction

AbstractFenton’s reaction is an advanced oxidation process where, classically, hydrogen peroxide is the oxidizing agent and an iron catalyst promotes the formation of hydroxyl radicals (•OH). Among the studies that evaluated different metals as Fenton-like catalysts, our group of investigation has recently used cerium-based solids as heterogeneous catalysts in slurry reaction and, in this work, iron sludge coming from an industrial Fenton’s reactor used for the wastewater depuration of a detergent production factory is being appraised while treating a synthetic effluent containing 0.1 g.L

scholarly journals Decontamination of N95 and surgical masks using a treatment based on a continuous gas phase-Advanced Oxidation Process

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248487
Author(s):  
Mahdiyeh Hasani ◽  
Tracey Campbell ◽  
Fan Wu ◽  
Keith Warriner
Keyword(s):  
Hydrogen Peroxide ◽  
Gas Phase ◽  
Hydroxyl Radicals ◽  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
Continuous Process ◽  
Oxidative Polymerization ◽  
Advanced Oxidation ◽  
Surgical Masks ◽  
Uv C

A gas-phase Advanced Oxidation Process (gAOP) was evaluated for decontaminating N95 and surgical masks. The continuous process was based on the generation of hydroxyl-radicals via the UV-C (254 nm) photo-degradation of hydrogen peroxide and ozone. The decontamination efficacy of the gAOP was dependent on the orientation of the N95 mask passing through the gAOP unit with those positioned horizontally enabling greater exposure to hydroxyl-radicals compared to when arranged vertically. The lethality of gAOP was independent of the applied hydrogen peroxide concentration (2–6% v/v) but was significantly (P<0.05) higher when H2O2 was introduced into the unit at 40 ml/min compared to 20 ml/min. A suitable treatment for N95 masks was identified as 3% v/v hydrogen peroxide delivered into the gAOP reactor at 40 ml/min with continuous introduction of ozone gas and a UV-C dose of 113 mJ/cm2 (30 s processing time). The treatment supported >6 log CFU decrease in Geobacillus stearothermophilus endospores, > 8 log reduction of human coronavirus 229E, and no detection of Escherichia coli K12 on the interior and exterior of masks. There was no negative effect on the N95 mask fitting or particulate efficacy after 20 passes through the gAOP system. No visual changes or hydrogen peroxide residues were detected (<1 ppm) in gAOP treated masks. The optimized gAOP treatment could also support >6 log CFU reduction of endospores inoculated on the interior or exterior of surgical masks. G. stearothermophilus Apex spore strips could be applied as a biological indicator to verify the performance of gAOP treatment. Also, a chemical indicator based on the oxidative polymerization of pyrrole was found suitable for reporting the generation of hydroxyl-radicals. In conclusion, gAOP is a verifiable treatment that can be applied to decontaminate N95 and surgical masks without any negative effects on functionality.

scholarly journals Different Inactivation Behaviors of MS-2 Phage and Escherichia coli in TiO2 Photocatalytic Disinfection

2005 ◽  
Vol 71 (1) ◽  
pp. 270-275 ◽  
Author(s):  
Min Cho ◽  
Hyenmi Chung ◽  
Wonyong Choi ◽  
Jeyong Yoon
Keyword(s):  
Escherichia Coli ◽  
Hydroxyl Radical ◽  
Hydroxyl Radicals ◽  
Mode Of Action ◽  
Microbial Inactivation ◽  
Chemical Degradation ◽  
Main Role ◽  
Chlorobenzoic Acid ◽  
E Coli ◽  
Hydroxyl Radical Scavengers

ABSTRACT Despite a wealth of experimental evidence concerning the efficacy of the biocidal action associated with the TiO2 photocatalytic reaction, our understanding of the photochemical mechanism of this particular biocidal action remains largely unclear. It is generally accepted that the hydroxyl radical (�OH), which is generated on the surface of UV-illuminated TiO2, plays the main role. However, our understanding of the exact mode of action of the hydroxyl radical in killing microorganisms is far from complete, and some studies report that other reactive oxygen species (ROS) (H2O2 and O2�−, etc.) also play significant roles. In particular, whether hydroxyl radicals remain bound to the surface or diffuse into the solution bulk is under active debate. In order to examine the exact mode of action of ROS in inactivating the microorganism, we tested and compared the levels of photocatalytic inactivation of MS-2 phage and Escherichia coli as representative species of viruses and bacteria, respectively. To compare photocatalytic microbial inactivation with the photocatalytic chemical degradation reaction, para-chlorobenzoic acid, which rapidly reacts with a hydroxyl radical with a diffusion-limited rate, was used as a probe compound. Two different hydroxyl radical scavengers, tert-butanol and methanol, and an activator of the bulk phase hydroxyl radical generation, Fe2+, were used to investigate their effects on the photocatalytic mode of action of the hydroxyl radical in inactivating the microorganism. The results show that the biocidal modes of action of ROS are very different depending on the specific microorganism involved, although the reason for this is not clear. It seems that MS-2 phage is inactivated mainly by the free hydroxyl radical in the solution bulk but that E. coli is inactivated by both the free and the surface-bound hydroxyl radicals. E. coli might also be inactivated by other ROS, such as O2�− and H2O2, according to the present results.

Inactivation of Nonpathogenic Escherichia coli, Escherichia coli O157:H7, Salmonella enterica Typhimurium, and Listeria monocytogenes in Ice Using a UVC Light-Emitting Diode

2017 ◽  
Vol 80 (7) ◽  
pp. 1198-1203 ◽  
Author(s):  
Suguru Murashita ◽  
Shuso Kawamura ◽  
Shigenobu Koseki
Keyword(s):  
Escherichia Coli ◽  
Food Industry ◽  
Light Emitting Diode ◽  
Microbial Inactivation ◽  
Distilled Water ◽  
Light Emitting ◽  
E Coli ◽  
Uv Lamp ◽  
Uv Dose ◽  
Led Irradiation

ABSTRACT Ice, widely used in the food industry, is a potential cause of food poisoning resulting from microbial contamination. Direct microbial inactivation of ice is necessary because microorganisms may have been present in the source water used to make it and/or may have been introduced due to poor hygiene during production or handling of the ice. Nonthermal and nondestructive microbial inactivation technologies are needed to control microorganisms in ice. We evaluated the applicability of a UVC light-emitting diode (UVC-LED) for microbial inactivation in ice. The effects of UV intensity and UV dose of the UVC-LED on Escherichia coli ATCC 25922 and a comparison of UVC-LED with a conventional UV lamp for effective bacterial inactivation in distilled water and ice cubes were investigated to evaluate the performance of the UVC-LED. Finally, we assessed the effects of the UVC-LED on pathogens such as E. coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in ice cubes. The results indicated that UVC-LED effectiveness depended on the UV dose at all UV intensity conditions (0.084, 0.025, 0.013, 0.007, and 0.005 mW/cm2) in ice and that UVC-LED could more efficiently inactivate E. coli ATCC 25922 in distilled water and ice than the UV lamp. At a UV dose of 2.64 mJ/cm2, E. coli in distilled water was decreased by 0.90 log CFU/mL (UV lamp) and by more than 7.0 log CFU/mL (UVC-LED). At 15.2 mJ/cm2, E. coli in ice was decreased by 3.18 log CFU/mL (UV lamp) and by 4.45 CFU/mL (UVC-LED). Furthermore, UVC-LED irradiation reduced the viable number of pathogens by 6 to 7 log cycles at 160 mJ/cm2, although the bactericidal effect was somewhat dependent on the type of bacteria. L. monocytogenes in ice was relatively more sensitive to UVC irradiation than were E. coli O157:H7 and Salmonella Typhimurium. These results demonstrate that UVC-LED irradiation could contribute to the safety of ice in the food industry.

A new surface wiping test to study surface disinfection by a novel chemical combination

2020 ◽  
Author(s):  
Joana F. Malheiro ◽  
Fernanda Borges ◽  
Jean-Yves Maillard ◽  
Manuel Simões
Keyword(s):  
Limit Of Detection ◽  
Mechanical Action ◽  
Test Method ◽  
Cross Resistance ◽  
Ammonium Compound ◽  
Surface Disinfection ◽  
Public Health Burden ◽  
E Coli ◽  
Healthcare Settings ◽  
Engineering Environment

&lt;p&gt;Effective biofilm disinfection is difficult to be implemented in healthcare settings and industry. In particular, surface disinfection is crucial to prevent microbial contaminations. However, disinfectants misuse has led to an increased concern on the existence of resistance and cross-resistance phenomena due to inadequate disinfection practices. The purpose of this study was the development of a formulation to be used for surface disinfection with wipes. The idea was to produce a formulation based on the combination between the quaternary ammonium compound - cetyltrimethylammonium bromide (CTAB) and a natural product - cinnamaldehyde. In addition, a new disc methodology to assess wiping efficiency was developed based on the Wiperator test (E2967-15) and on the quantitative test method for the evaluation of bactericidal and yeasticidal activity on non-porous surfaces with mechanical action employing wipes in the medical area, 4- field test (EN 16615:2015). The combination of CTAB and cinnamaldehyde was synergic in terms of antimicrobial action against Escherichia coli and Staphylococcus aureus. After stablishing the final formulation, wiping efficacy was assessed with the new methodology. In this case, a contaminated surface (6.20 &amp;#177; 0.21 log&lt;sub&gt;10&lt;/sub&gt; CFU of E. coli and 7.10 &amp;#177; 0.06 log&lt;sub&gt;10&lt;/sub&gt; CFU of S. aureus) was wiped using two different wipes in terms of composition, thickness and porosity (A and B). After wiping the contaminated surface with wipe A, without the formulation, 3.42 &amp;#177; 0.46 log&lt;sub&gt;10&lt;/sub&gt; CFU (E. coli) and 5.38 &amp;#177; 0.20 log&lt;sub&gt;10&lt;/sub&gt; CFU (S. aureus) remained on the surface while in the presence of the formulation the bacteria present were under the limit of detection for E. coli and 2.76 &amp;#177; 0.22 log&lt;sub&gt;10&lt;/sub&gt; CFU for S. aureus. The formulation was also able to prevent the transfer of bacteria to clean surfaces after wiping the contaminated surface. In the case of wipe A, after wiping the contaminated surface and the subsequent 2 clean surfaces, a total reduction of 4.35 &amp;#177; 0.22 log&lt;sub&gt;10&lt;/sub&gt; CFU and 4.27 &amp;#177; 0.22 log&lt;sub&gt;10&lt;/sub&gt; CFU was achieved when the wipe was impregnated with the formulation in comparison with 2.45 &amp;#177; 0.41 log&lt;sub&gt;10&lt;/sub&gt; CFU and 1.50 &amp;#177; 0.35 log&lt;sub&gt;10&lt;/sub&gt; CFU of removal just by mechanical action for E. coli and S. aureus, respectively. For wipe B a general lower reduction was observed but the same behaviour was detected with the use of the formulation when comparison to just mechanical action. This work highlights the enormous potential of combinatorial approach to increase the efficacy of already used biocides diminishing their in-use concentration and consequently their environmental and public health burden.&lt;/p&gt; &lt;p&gt;&amp;#160;&lt;/p&gt; &lt;p&gt;&lt;strong&gt;Acknowledgements&lt;/strong&gt;&lt;/p&gt; &lt;p&gt;This work was financed by: UIDB/00511/2020 of the Laboratory for Process Engineering, Environment, Biotechnology and Energy &amp;#8211; LEPABE - funded by national funds through the FCT/MCTES (PIDDAC); POCI-01-0145-FEDER-030219, POCI-01-0247-FEDER-035234; POCI-01-0145-FEDER-028397; POCI-01-0247-FEDER-033298; POCI-01-0145-FEDER-006939, funded by FEDER through COMPETE2020 &amp;#8211; Programa Operacional Competitividade e Internacionaliza&amp;#231;&amp;#227;o (POCI) and by national funds (PIDDAC) through FCT/MCTES. Grant attributed by Portuguese Foundation for Science and Technology (FCT) to Joana Malheiro (SFRH/BD/103843/2014) and Manuel Sim&amp;#245;es (SFRH/BSAB/150379/2019).&lt;/p&gt;

scholarly journals Antimicrobial Efficacy and Spectrum of Phosphorous-Fluorine Co-Doped TiO2 Nanoparticles on the Foodborne Pathogenic Bacteria Campylobacter jejuni, Salmonella Typhimurium, Enterohaemorrhagic E. coli, Yersinia enterocolitica, Shewanella putrefaciens, Listeria monocytogenes and Staphylococcus aureus

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1786
Author(s):  
György Schneider ◽  
Bettina Schweitzer ◽  
Anita Steinbach ◽  
Botond Zsombor Pertics ◽  
Alysia Cox ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Campylobacter Jejuni ◽  
Food Industry ◽  
Pathogenic Bacteria ◽  
Antibacterial Activities ◽  
Tio2 Nps ◽  
E Coli ◽  
Foodborne Pathogenic Bacteria ◽  
And Staphylococcus Aureus ◽  
Co Doped

Contamination of meats and meat products with foodborne pathogenic bacteria raises serious safety issues in the food industry. The antibacterial activities of phosphorous-fluorine co-doped TiO2 nanoparticles (PF-TiO2) were investigated against seven foodborne pathogenic bacteria: Campylobacter jejuni, Salmonella Typhimurium, Enterohaemorrhagic E. coli, Yersinia enterocolitica, Shewanella putrefaciens, Listeria monocytogenes and Staphylococcus aureus. PF-TiO2 NPs were synthesized hydrothermally at 250 °C for 1, 3, 6 or 12 h, and then tested at three different concentrations (500 μg/mL, 100 μg/mL, 20 μg/mL) for the inactivation of foodborne bacteria under UVA irradiation, daylight exposure or dark conditions. The antibacterial efficacies were compared after 30 min of exposure to light. Distinct differences in the antibacterial activities of the PF-TiO2 NPs, and the susceptibilities of tested foodborne pathogenic bacterium species were found. PF-TiO2/3 h and PF-TiO2/6 h showed the highest antibacterial activity by decreasing the living bacterial cell number from ~106 by ~5 log (L. monocytogenes), ~4 log (EHEC), ~3 log (Y. enterolcolitca, S. putrefaciens) and ~2.5 log (S. aureus), along with complete eradication of C. jejuni and S. Typhimurium. Efficacy of PF-TiO2/1 h and PF-TiO2/12 h NPs was lower, typically causing a ~2–4 log decrease in colony forming units depending on the tested bacterium while the effect of PF-TiO2/0 h was comparable to P25 TiO2, a commercial TiO2 with high photocatalytic activity. Our results show that PF-co-doping of TiO2 NPs enhanced the antibacterial action against foodborne pathogenic bacteria and are potential candidates for use in the food industry as active surface components, potentially contributing to the production of meats that are safe for consumption.

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