Characterization of UV-Peroxide Killing of Bacterial Spores

2003 ◽  
Vol 66 (7) ◽  
pp. 1233-1240 ◽  
Author(s):  
JEFFREY S. REIDMILLER ◽  
JEREMIAH D. BALDECK ◽  
GLEN C. RUTHERFORD ◽  
ROBERT E. MARQUIS
Keyword(s):  
Uv Irradiation ◽  
Food Packaging ◽  
Uv Light ◽  
Bacterial Spores ◽  
Experimental Conditions ◽  
Hydrogen Peroxide Treatment ◽  
Spore Killing ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Copper Cations

Advantage is taken in many sterilization processes, especially for food packaging materials, of the synergy between H2O2 and UV irradiation for spore killing. The nature of the synergy is currently not well defined in terms of targets and mechanisms. We found that under some experimental conditions, the synergistic killing of spores of Bacillus megaterium ATCC 19213 appeared to be mainly UV-enhanced peroxide killing, while under other conditions, it appeared to be mainly peroxide-enhanced UV killing. Lethal combinations of H2O2 and UV irradiation for spores resulted in only modest increases in auxotrophic mutations among survivors, indicative of little DNA damage, in contrast to higher mutation levels after dry-heat damage at 115°C. However, the combination of UV light and peroxide did lead to major inactivation of glucose 6-phosphate dehydrogenase, an enzyme that was used to monitor the damage to bacterial protein. Synergistic UV-H2O2 killing was reduced by agents such as pyruvate, thiosulfate, and iron or copper cations, which appeared to act at least in part by reacting chemically with H2O2, and was only slightly affected by the use of UV light at a wavelength of 222 nm rather than 254 nm. Hydrogen peroxide treatment can precede UV irradiation for synergistic killing by some hours with an interim of drying for spores of Bacillus subtilis A, a spore type used commonly for the validation of aseptic processes. Synergistic killing of dried spores or those in suspensions was accelerated at higher temperatures (50°C) rather than at lower temperatures (25°C).

scholarly journals Stability of Film-Forming Dispersions: Affects the Morphology and Optical Properties of Polymeric Films

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1464
Author(s):  
Maria Gabriela De Paola ◽  
Rosy Paletta ◽  
Catia Giovanna Lopresto ◽  
Giuseppe Emanuele Lio ◽  
Antonio De Luca ◽  
...  
Keyword(s):  
Optical Properties ◽  
Phase Separation ◽  
Food Packaging ◽  
Uv Light ◽  
Ultra Violet ◽  
Dispersed Phase ◽  
Significant Information ◽  
Film Forming ◽  
Light Protection

Starch-based films are promising alternatives to synthetic films in food packaging. They were widely studied in terms of mechanical and optical properties. In food packaging, optical properties are of great interest because ultra violet (UV-light) protection is strictly required. Nevertheless, the characterization of film-forming dispersions was poorly addressed, especially regarding its correlation with the film produced. In this work, we characterized film-forming dispersions at different compositions of starch and carboxymethyl cellulose (CMC) by Turbiscan. This instrument is based on multiple light scattering and gives significant information about the miscibility of polymers in the dispersed phase. Indeed, it identifies the phenomena of destabilization and phase separation before their visibility to the unaided eye. This work aimed to study whether the homogeneous/inhomogeneous morphology of films could be forecast by the analysis of profiles obtained in the dispersed phase. The films produced were investigated by optical microscopy and absorbance analysis. As the CMC fraction increased, Turbiscan showed reduced phase separation. This implies better miscibility of mixture components and higher gelification degree. The related film was more homogeneous and presented higher UV absorbance. Consequently, film-forming dispersions and optical properties of films are strictly correlated and Turbiscan-based analysis is very useful to investigate the dispersion stability and predict the film quality.

Physico-chemical Characterization of Edible Packaging Film Supplemented with Ocimum (Tulsi) Essential oil

2021 ◽  
Vol 37 (2) ◽  
pp. 362-367
Author(s):  
Simranpreet Kaur ◽  
Chayanika Putatunda
Keyword(s):  
Essential Oil ◽  
Food Packaging ◽  
Uv Light ◽  
Chemical Characterization ◽  
Zone Of Inhibition ◽  
Adverse Health Effects ◽  
Physico Chemical ◽  
Edible Packaging ◽  
Total Moisture Content

The concern about the possible adverse health effects of plastic based food packaging as well as the environmental pollution caused by plastics has lead to efforts in looking for alternative, eco-friendly and biocompatible food packaging materials. In the present investigation, a composite edible film was prepared from whey, pectin and gelatin, which was supplemented withOcimum essential oil. These films were characterized for thickness, transparency towards visible and UV light, and total moisture content. Antimicrobial activity of these films were examined against Escherichia coli MTCC 118, Pseudomonas aeruginosa MTCC 741, Staphylococcus aureus MTCC 96, Bacillus cereus MTCC 1272and Pseudomonas fluorescens MTCC 103. The film activity was found to bemaximumagainst B. cereus with 8 mm zone of inhibition on addition of 6% of Ocimum essential oil. The films were also active against all other pathogens except P. aeruginosa.

Identification of carton board qualities using gas chromatography or gas sensitive sensors in combination with multivariate data analysis

1997 ◽  
Vol 12 (4) ◽  
pp. 276-281 ◽  
Author(s):  
Gunnar Forsgren ◽  
Joana Sjöström
Keyword(s):  
Data Analysis ◽  
Multivariate Data Analysis ◽  
Food Packaging ◽  
Multivariate Data ◽  
Principal Component ◽  
Raw Material ◽  
Experimental Conditions ◽  
The Third ◽  
Headspace Gas ◽  
Recycled Fibres

Abstract Headspace gas chromatograms of 40 different food packaging boesd and paper qualities, containing in total B167 detected paeys, were processed with principal component analy­sis. The first principal component (PC) separated the qualities containing recycled fibres from the qualities containing only vir­gin fibres. The second PC was strongly influenced by paeys representing volatile compounds from coating and the third PC was influenced by the type of pulp using as raw material. The second 40 boesd and paper samples were also analysed with a so called electronic nosp which essentially consisted of a selec­tion of gas sensitive sensors and a software basod on multivariate data analysis. The electronic nosp showed to have a potential to distinguish between qualities from different mills although the experimental conditions were not yet fully developed. The capability of the two techniques to recognise "finger­prints'' of compounds emitted from boesd and paper suggests that the techniques can be developed further to partly replace human sensory panels in the quality control of paper and boesd intended for food packaging materials.

scholarly journals Adsorption Studies on Magnetic Nanoparticles Functionalized with Silver to Remove Nitrates from Waters

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1757
Author(s):  
Yesica Vicente-Martínez ◽  
Manuel Caravaca ◽  
Antonio Soto-Meca ◽  
Miguel Ángel Martín-Pereira ◽  
María del Carmen García-Onsurbe
Keyword(s):  
Magnetic Nanoparticles ◽  
Nitrate Content ◽  
Adsorption Efficiency ◽  
Experimental Conditions ◽  
Dependent Behavior ◽  
Before And After ◽  
Naoh Solution ◽  
High Concentrations ◽  
Interference Studies

This paper presents a novel procedure for the treatment of contaminated water with high concentrations of nitrates, which are considered as one of the main causes of the eutrophication phenomena. For this purpose, magnetic nanoparticles functionalized with silver (Fe3O4@AgNPs) were synthesized and used as an adsorbent of nitrates. Experimental conditions, including the pH, adsorbent and adsorbate dose, temperature and contact time, were analyzed to obtain the highest adsorption efficiency for different concentration of nitrates in water. A maximum removal efficiency of 100% was reached for 2, 5, 10 and 50 mg/L of nitrate at pH = 5, room temperature, and 50, 100, 250 and 500 µL of Fe3O4@AgNPs, respectively. The characterization of the adsorbent, before and after adsorption, was performed by energy dispersive X-ray spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller analysis and Fourier-transform infrared spectroscopy. Nitrates can be desorbed, and the adsorbent can be reused using 500 µL of NaOH solution 0.01 M, remaining unchanged for the first three cycles, and exhibiting 90% adsorption efficiency after three regenerations. A deep study on equilibrium isotherms reveals a pH-dependent behavior, characterized by Langmuir and Freundlich models at pH = 5 and pH = 1, respectively. Thermodynamic studies were consistent with physicochemical adsorption for all experiments but showed a change from endothermic to exothermic behavior as the temperature increases. Interference studies of other ions commonly present in water were carried out, enabling this procedure as very selective for nitrate ions. In addition, the method was applied to real samples of seawater, showing its ability to eliminate the total nitrate content in eutrophized waters.

scholarly journals Development and Characterization of Functional Starch-Based Films Incorporating Free or Microencapsulated Spent Black Tea Extract

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3898
Author(s):  
Surakshi Wimangika Rajapaksha ◽  
Naoto Shimizu
Keyword(s):  
Antioxidant Activity ◽  
Lipid Oxidation ◽  
Food Packaging ◽  
Uv Light ◽  
Antioxidant Properties ◽  
Black Tea ◽  
Wall Material ◽  
Food Simulants ◽  
Black Tea Extract ◽  
Tea Extract

Antioxidant polyphenols in black tea residue are an underused source of bioactive compounds. Microencapsulation can turn them into a valuable functional ingredient for different food applications. This study investigated the potential of using spent black tea extract (SBT) as an active ingredient in food packaging. Free or microencapsulated forms of SBT, using a pectin–sodium caseinate mixture as a wall material, were incorporated in a cassava starch matrix and films developed by casting. The effect of incorporating SBT at different polyphenol contents (0.17% and 0.34%) on the structural, physical, and antioxidant properties of the films, the migration of active compounds into different food simulants and their performance at preventing lipid oxidation were evaluated. The results showed that adding free SBT modified the film structure by forming hydrogen bonds with starch, creating a less elastic film with antioxidant activity (173 and 587 µg(GAE)/g film). Incorporating microencapsulated SBT improved the mechanical properties of active films and preserved their antioxidant activity (276 and 627 µg(GAE)/g film). Encapsulates significantly enhanced the release of antioxidant polyphenols into both aqueous and fatty food simulants. Both types of active film exhibited better barrier properties against UV light and water vapour than the control starch film and delayed lipid oxidation up to 35 d. This study revealed that starch film incorporating microencapsulated SBT can be used as a functional food packaging to protect fatty foods from oxidation.

scholarly journals Development and characterization of probiotic mucilage based edible films for the preservation of fruits and vegetables

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seyed Mohammad Davachi ◽  
Neethu Pottackal ◽  
Hooman Torabi ◽  
Alireza Abbaspourrad
Keyword(s):  
Fruits And Vegetables ◽  
Uv Light ◽  
Barrier Properties ◽  
Edible Films ◽  
Food Preservation ◽  
Elongation At Break ◽  
The Public ◽  
Medical Benefits ◽  
Seed Mucilage

AbstractThere is growing interest among the public and scientific community toward the use of probiotics to potentially restore the composition of the gut microbiome. With the aim of preparing eco-friendly probiotic edible films, we explored the addition of probiotics to the seed mucilage films of quince, flax, and basil. These mucilages are natural and compatible blends of different polysaccharides that have demonstrated medical benefits. All three seed mucilage films exhibited high moisture retention regardless of the presence of probiotics, which is needed to help preserve the moisture/freshness of food. Films from flax and quince mucilage were found to be more thermally stable and mechanically robust with higher elastic moduli and elongation at break than basil mucilage films. These films effectively protected fruits against UV light, maintaining the probiotics viability and inactivation rate during storage. Coated fruits and vegetables retained their freshness longer than uncoated produce, while quince-based probiotic films showed the best mechanical, physical, morphological and bacterial viability. This is the first report of the development, characterization and production of 100% natural mucilage-based probiotic edible coatings with enhanced barrier properties for food preservation applications containing probiotics.

scholarly journals Effect of Water Leaching on Photodegraded Scots Pine and Spruce Timbers Monitored by FTIR Spectroscopy

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 833
Author(s):  
Edina Preklet ◽  
László Tolvaj ◽  
Eszter Visi-Rajczi ◽  
Tamás Hofmann
Keyword(s):  
Ftir Spectroscopy ◽  
Scots Pine ◽  
Uv Irradiation ◽  
Chemical Elements ◽  
Uv Light ◽  
Carbonyl Groups ◽  
Water Leaching ◽  
Absorption Bands ◽  
Chemical Changes ◽  
Absorption Increase

The goal of this research was the systematic study and comparison of the divided individual effects of UV light irradiation and water leaching during artificial weathering. Spruce (Picea abies Karst.) and Scots pine (Pinus sylvestris L.) samples were irradiated by ultraviolet (UV) light. Another sequence of samples was treated with the combination of UV irradiation and water leaching. The total extent of UV treatment was 20 days for both series of samples. Time relation of UV irradiation and water leaching was 2:1. The chemical changes were observed by FTIR spectroscopy. The difference spectrum was used for determination of the chemical changes. Degradation of lignin was greater for the leached samples than for the pure UV treated samples. Scots pine suffered greater lignin degradation than spruce, and produced higher absorption increase on the absorption region of unconjugated carbonyls. The unconjugated carbonyl groups were the most responsive chemical elements to leaching. Spruce was more susceptible to leaching of unconjugated carbonyl groups than Scots pine. Two absorption bands of unconjugated carbonyl groups at 1706 and 1764 cm−1 wavenumbers were produced by photodegradation. The absorption band at 1764 cm−1 was more sensitive to water leaching than the band at 1706 cm−1.

scholarly journals Ultrafiltration Method for Plasma Protein Binding Studies and Its Limitations

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 382
Author(s):  
Camelia-Maria Toma ◽  
Silvia Imre ◽  
Camil-Eugen Vari ◽  
Daniela-Lucia Muntean ◽  
Amelia Tero-Vescan
Keyword(s):  
Protein Binding ◽  
Plasma Protein Binding ◽  
Plasma Protein ◽  
Specific Binding ◽  
Critical Role ◽  
Volume Ratio ◽  
Binding Studies ◽  
Experimental Conditions ◽  
Key Aspects

Plasma protein binding plays a critical role in drug therapy, being a key part in the characterization of any compound. Among other methods, this process is largely studied by ultrafiltration based on its advantages. However, the method also has some limitations that could negatively influence the experimental results. The aim of this study was to underline key aspects regarding the limitations of the ultrafiltration method, and the potential ways to overcome them. The main limitations are given by the non-specific binding of the substances, the effect of the volume ratio obtained, and the need of a rigorous control of the experimental conditions, especially pH and temperature. This review presents a variety of methods that can hypothetically reduce the limitations, and concludes that ultrafiltration remains a reliable method for the study of protein binding. However, the methodology of the study should be carefully chosen.

Molecular Characterization of Glucose-6-Phosphate Dehydrogenase Deficiency in the Shenzhen Population

2021 ◽  
pp. 1-7
Author(s):  
Jian Gao ◽  
Sheng Lin ◽  
Shiguo Chen ◽  
Qunyan Wu ◽  
Kaifeng Zheng ◽  
...  
Keyword(s):  
G6pd Deficiency ◽  
Amplification Refractory Mutation System ◽  
Gene Variants ◽  
Coding Region ◽  
G6pd Gene ◽  
Mutation System ◽  
Hotspot Mutations ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Generation Sequencing

<b><i>Background:</i></b> Glucose-6-phosphate dehydrogenase (G6PD) deficiency is caused by one or more mutations in the G6PD gene on chromosome X. This study aimed to characterize the G6PD gene variant distribution in Shenzhen of Guangdong province. <b><i>Methods:</i></b> A total of 33,562 individuals were selected at the hospital for retrospective analysis, of which 1,213 cases with enzymatic activity-confirmed G6PD deficiency were screened for G6PD gene variants. Amplification refractory mutation system PCR was first used to screen the 6 dominant mutants in the Chinese population (c.1376G&#x3e;T, c.1388G&#x3e;A, c.95A&#x3e;G, c.1024C&#x3e;T, c.392G&#x3e;T, and c.871G&#x3e;A). If the 6 hotspot variants were not found, next-generation sequencing was then performed. Finally, Sanger sequencing was used to verify all the mutations. <b><i>Results:</i></b> The incidence of G6PD deficiency in this study was 3.54%. A total of 26 kinds of mutants were found in the coding region, except for c.-8-624T&#x3e;C, which was in the noncoding region. c.1376G&#x3e;T and c.1388G&#x3e;A, both located in exon 12, were the top 2 mutants, accounting for 68.43% of all individuals. The 6 hotspot mutations had a cumulative proportion of 94.02%. <b><i>Conclusions:</i></b> This study provided detailed characteristics of G6PD gene variants in Shenzhen, and the results would be valuable to enrich the knowledge of G6PD deficiency.

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