scholarly journals Development and Evaluation of a Reflective Solar Disinfection Pouch for Treatment of Drinking Water

2004 ◽  
Vol 70 (4) ◽  
pp. 2545-2550 ◽  
Author(s):  
D. Carey Walker ◽  
Soo-Voon Len ◽  
Brita Sheehan
Keyword(s):  
Antimicrobial Properties ◽  
Microbiological Quality ◽  
Water Source ◽  
Packaging Materials ◽  
Culturable Bacteria ◽  
Food Grade ◽  
Solar Disinfection ◽  
Log Reduction ◽  
Bacteriophage Ms2 ◽  
Time Period

ABSTRACT A second-generation solar disinfection (SODIS) system (pouch) was constructed from food-grade, commercially available packaging materials selected to fully transmit and amplify the antimicrobial properties of sunlight. Depending upon the season, water source, and challenge organism, culturable bacteria were reduced between 3.5 and 5.5 log cycles. The system was also capable of reducing the background presumptive coliform population in nonsterile river water below the level of detection. Similar experiments conducted with a model virus, the F-specific RNA bacteriophage MS2, indicated that the pouch was slightly less efficient, reducing viable plaques by 3.5 log units in comparison to a 5.0 log reduction of enterotoxigenic Escherichia coli O18:H11 within the same time period. These results suggest that water of poor microbiological quality can be improved by using a freely available resource (sunlight) and a specifically designed plastic pouch constructed of food-grade packaging materials.

scholarly journals Sodium hypochlorite dosage for household and emergency water treatment: updated recommendations

2017 ◽  
Vol 16 (1) ◽  
pp. 112-125 ◽  
Author(s):  
Natalie Wilhelm ◽  
Anya Kaufmann ◽  
Elizabeth Blanton ◽  
Daniele Lantagne
Keyword(s):  
Water Treatment ◽  
Sodium Hypochlorite ◽  
Diarrheal Disease ◽  
Microbiological Quality ◽  
Water Source ◽  
Field Studies ◽  
Household Water Treatment ◽  
E Coli ◽  
Log Reduction ◽  
Household Water

Abstract Household water treatment with chlorine can improve the microbiological quality of household water and reduce diarrheal disease. We conducted laboratory and field studies to inform chlorine dosage recommendations. In the laboratory, reactors of varying turbidity (10–300 NTU) and total organic carbon (0–25 mg/L addition) were created, spiked with Escherichia coli, and dosed with 3.75 mg/L sodium hypochlorite. All reactors had >4 log reduction of E. coli 24 hours after chlorine addition. In the field, we tested 158 sources in 22 countries for chlorine demand. A 1.88 mg/L dosage for water from improved sources of <5 or <10 NTU turbidity met free chlorine residual criteria (≤2.0 mg/L at 1 hour, ≥0.2 mg/L at 24 hours) 91–94% and 82–87% of the time at 8 and 24 hours, respectively. In unimproved water source samples, a 3.75 mg/L dosage met relaxed criteria (≤4.0 mg/L at 1 hour, ≥0.2 mg/L after 24 hours) 83% and 65% of the time after 8 and 24 hours, respectively. We recommend water from improved/low turbidity sources be dosed at 1.88 mg/L and used within 24 hours, and from unimproved/higher turbidity sources be dosed at 3.75 mg/L and consumed within 8 hours. Further research on field effectiveness of chlorination is recommended.

scholarly journals Physicochemical and Antimicrobial Properties of Cocoa Pod Husk Pectin Intended as a Versatile Pharmaceutical Excipient and Nutraceutical

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Ofosua Adi-Dako ◽  
Kwabena Ofori-Kwakye ◽  
Samuel Frimpong Manso ◽  
Mariam EL Boakye-Gyasi ◽  
Clement Sasu ◽  
...  
Keyword(s):  
Aqueous Media ◽  
Antimicrobial Properties ◽  
Microbiological Quality ◽  
Elemental Content ◽  
Moderate Activity ◽  
Pharmaceutical Excipient ◽  
E Coli ◽  
Swelling Capacity ◽  
Weak Activity ◽  
Cocoa Pod Husk

The physicochemical and antimicrobial properties of cocoa pod husk (CPH) pectin intended as a versatile pharmaceutical excipient and nutraceutical were studied. Properties investigated include pH, moisture content, ash values, swelling index, viscosity, degree of esterification (DE), flow properties, SEM, FTIR, NMR, and elemental content. Antimicrobial screening and determination of MICs against test microorganisms were undertaken using agar diffusion and broth dilution methods, respectively. CPH pectin had a DE of 26.8% and exhibited good physicochemical properties. Pectin had good microbiological quality and exhibited pseudoplastic, shear thinning behaviour, and high swelling capacity in aqueous media. The DE, FTIR, and NMR results were similar to those of previous studies and supported highly acetylated low methoxy pectin. CPH pectin was found to be a rich source of minerals and has potential as a nutraceutical. Pectin showed dose-dependent moderate activity against gram positive and gram negative microorganisms but weak activity against Listeria spp. and A. niger. The MICs of pectin ranged from 0.5 to 4.0 mg/mL, with the highest activity against E. coli and S. aureus (MIC: 0.5–1.0 mg/mL) and the lowest activity against A. niger (MIC: 2.0–4.0 mg/mL). The study has demonstrated that CPH pectin possesses the requisite properties for use as a nutraceutical and functional pharmaceutical excipient.

A Method for Evaluating the Thermal Performance of Passenger Seats

2003 ◽  
Vol 217 (6) ◽  
pp. 449-459 ◽  
Author(s):  
E B Ratts ◽  
J W McElroy ◽  
W G Reed
Keyword(s):  
Thermal Performance ◽  
Thermal Energy ◽  
Water Source ◽  
Fixed Time ◽  
Test Method ◽  
Test Apparatus ◽  
Passenger Seat ◽  
Time Period ◽  
Seat Cushion ◽  
Heat And Moisture

In this paper, an experimental method to quantify the capability of an automotive seat to move heat and moisture away from the heat and water source is presented. To test the method, a test apparatus was constructed that generates heat and water vapour. The apparatus was placed on a seat cushion for a fixed time period. At the end of the period, heat and water transported were measured. These integrated values were used to quantify the seat's capability to move heat and moisture and ultimately to compare seats. By the impulse test method, the passenger seat had an effusivity of 94.7 W s1/2/m2 K. A non-ventilated seat transferred 5 W of thermal energy and an average of 0.36 g/min of water in 1800 s. A ventilated seat transferred 13.9 W of thermal energy and 0.70 g/min of water in 1800 s.

scholarly journals Viability of lactic acid bacteria in different components of Ogi with anti diarrhoeagenic E. coli activities

2019 ◽  
Vol 3 (6) ◽  
pp. 206-213
Author(s):  
Roseline Eleojo Kwasi ◽  
Iyanuoluwa Gladys Aremu ◽  
Qudus Olamide Dosunmu ◽  
Funmilola A. Ayeni
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Antimicrobial Properties ◽  
Culture Method ◽  
Antimicrobial Activities ◽  
Drying Methods ◽  
Bacterial Strains ◽  
E Coli ◽  
Log Reduction ◽  
Freeze Dried

Background: Ogi constitutes a rich source of lactic acid bacteria (LAB) with associated health benefits to humans through antimicrobial activities. However, the high viability of LAB in Ogi and its supernatant (Omidun) is essential. Aims: This study was carried out to assess the viability of LAB in various forms of modified and natural Ogi and the antimicrobial properties of Omidun against diarrhoeagenic E coli. Methods and Material: The viability of LAB was assessed in fermented Ogi slurry and Omidun for one month and also freeze-dried Ogi with and without added bacterial strains for two months. A further 10 days viability study of modified Omidun, refrigerated Omidun, and normal Ogi was performed. The antimicrobial effects of modified Omidun against five selected strains of diarrhoeagenic E. coli (DEC) were evaluated by the co-culture method. Results: Both drying methods significantly affected carotenoids and phenolic compounds. The Ogi slurry had viable LAB only for 10 days after which, there was a succession of fungi and yeast. Omidun showed 2 log10cfu/ml reduction of LAB count each week and the freeze-dried Ogi showed progressive reduction in viability. Refrigerated Omidun has little viable LAB, while higher viability was seen in modified Omidun (≥2 log cfu/ml) than normal Omidun. Modified Omidun intervention led to 2-4 log reduction in diarrhoeagenic E. coli strains and total inactivation of shigella-toxin producing E. coli H66D strain in co-culture. Conclusions: The consumption of Ogi should be within 10 days of milling using modified Omidun. There are practical potentials of consumption of Omidun in destroying E. coli strains implicated in diarrhea. Keywords: Ogi, Omidun, lactic acid bacteria, diarrhoeagenic Escherichia coli strains, Viability.

scholarly journals Quaternary Salts of Chitosan: History, Antimicrobial Features, and Prospects

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Douglas de Britto ◽  
Rejane Celi Goy ◽  
Sergio Paulo Campana Filho ◽  
Odilio B. G. Assis
Keyword(s):  
Physical Chemistry ◽  
Antimicrobial Activity ◽  
Drug Delivery Systems ◽  
Antimicrobial Properties ◽  
Water Soluble ◽  
Chemical Characteristics ◽  
Packaging Materials ◽  
Inhibitory Effects ◽  
Quaternary Salts ◽  
Derivatives Of

Recently, increasing attention has been paid to water-soluble derivatives of chitosan at its applications. The chemical characteristics and the antimicrobial properties of these salts can play significant role in pharmacological and food areas mainly as carriers for drug delivery systems and as antimicrobial packaging materials. In the current paper, a historical sequence of the main preparative methods, physical chemistry aspects, and antimicrobial activity of chitosan quaternized derivatives are presented and briefly discussed. In general, the results indicated that the quaternary derivatives had better inhibitory effects than the unmodified chitosan.

scholarly journals Photoactivated Self-Sanitizing Chlorophyllin-Containing Coatings to Prevent Microbial Contamination in Packaged Food

Coatings ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 328 ◽  
Author(s):  
Gracia López-Carballo ◽  
Pilar Hernández-Muñoz ◽  
Rafael Gavara
Keyword(s):  
Antimicrobial Activity ◽  
High Efficiency ◽  
Antimicrobial Properties ◽  
Methyl Cellulose ◽  
Log Reduction ◽  
Gram Positive Bacteria ◽  
Sodium Magnesium ◽  
Pet Film ◽  
Packaged Food ◽  
Sodium Copper Chlorophyllin

Chlorophyllins are semi-synthetic porphyrins obtained from chlorophyll that—when exposed to visible light—generate radical oxygen substances with antimicrobial activity. In this work, chlorophyllins incorporated with polyethylene (PE), polyvinyl alcohol (PVOH), (hydroxypropyl)methyl cellulose (HPMC), and gelatin (G) were formulated for application as coatings in packages providing antimicrobial activity after photoactivation. First, the antimicrobial properties of two porphyrins (sodium magnesium chlorophyllin, E-140, and sodium copper chlorophyllin, E-141) were analyzed against L. monocytogenes and Escherichia coli. The results indicated that E-140 was more active than E-141 and that chlorophyllins were more effective against Gram-positive bacteria. In addition, both chlorophyllins were more efficient when irradiated with halogen lamps than with LEDs, and they were inactive in dark conditions. Then, coatings on polyethylene terephthalate (PET) film were prepared, and their effect against the test bacteria was similar to that shown previously with pure chlorophyllins, i.e., greater activity in films containing E-140. Among the coating matrices, those based on PE presented the least effect (1 log reduction), whereas PVOH, HPMC, and G were lethal (7 log reduction). The self-sanitizing effect of these coatings was also analyzed by contaminating the surface of the coatings and irradiating them through the PET surface, which showed high efficiency, although the activity of the coatings was limited to L. monocytogenes. Finally, coated films were applied as separators of bologna slices. After irradiation, all the films showed count reductions of L. monocytogenes and the usual microbial load; the gelatin coating was the most effective, with an average of 3 log reduction.

Inactivation of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella in Cranberry, Lemon, and Lime Juice Concentrates

2003 ◽  
Vol 66 (9) ◽  
pp. 1637-1641 ◽  
Author(s):  
MARA C. L. NOGUEIRA ◽  
OMAR A. OYARZÁBAL ◽  
DAVID E. GOMBAS
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Pathogenic Bacteria ◽  
Antimicrobial Properties ◽  
Escherichia Coli O157 ◽  
Bacterial Inactivation ◽  
Lime Juice ◽  
E Coli ◽  
Log Reduction ◽  
C 32

The production of thermally concentrated fruit juices uses temperatures high enough to achieve at least a 5-log reduction of pathogenic bacteria that can occur in raw juice. However, the transportation and storage of concentrates at low temperatures prior to final packaging is a common practice in the juice industry and introduces a potential risk for postconcentration contamination with pathogenic bacteria. The present study was undertaken to evaluate the likelihood of Escherichia coli O157: H7, Listeria monocytogenes and Salmonella surviving in cranberry, lemon, and lime juice concentrates at or above temperatures commonly used for transportation or storage of these concentrates. This study demonstrates that cranberry, lemon, and lime juice concentrates possess intrinsic antimicrobial properties that will eliminate these bacterial pathogens in the event of postconcentration recontamination. Bacterial inactivation was demonstrated under all conditions; at least 5-log Salmonella inactivation was consistently demonstrated at −23°C (−10°F), at least 5-log E. coli O157:H7 inactivation was consistently demonstrated at −11°C (12°F), and at least 5-log L. monocytogenes inactivation was consistently demonstrated at 0°C (32°F).

Novel Bacterial Immobilization Compound Effectively Decreases Bacterial Counts in Healthy Volunteers

2010 ◽  
Vol 76 (1) ◽  
pp. 15-19 ◽  
Author(s):  
Diego F. Pabon ◽  
Michael J. Yost ◽  
Giselle C. Melendez ◽  
Tamsin M. Durand ◽  
Timothy Z. Brock ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Povidone Iodine ◽  
Antimicrobial Properties ◽  
Control Group ◽  
Skin Area ◽  
Bacterial Colony ◽  
Bacterial Counts ◽  
Log Reduction ◽  
Incisional Surgical Site Infection ◽  
Skin Flora

Skin flora immobilization technology is similar in efficacy to Iodine-Povidone in healthy volunteers. We did a prospective study in a university clinic with 60 healthy volunteers. Right inguinal skin area on healthy volunteers was used to compare the antimicrobial properties of cyanoacrylate sealant (FloraSeal, Adhesion Biomedical, Wyomissing, PA) versus standard surgical preparation Povidone-iodine (Betadine, Purdue Productions, Stamford, CT). Bacterial counts were measured at different time intervals: 15 minutes, 4 hours, and 24 hours. Bacterial colony forming units were compared between Povidone-iodine and cyanoacrylate sealant. The absolute log reduction was 5.568 for Povidone-iodine (7 absolute CFU); 5.028 for cyanoacrylate (59 absolute CFU); and 5.568 for Povidone-iodine and cyanoacrylate combined (21 absolute CFU). Cyanoacrylate was able to sustain a reduction on bacterial counts at 4 hours and 24 hours of more than 99.8 per cent as compared with the control group. Cyanoacrylate microbial sealant successfully reduces bacterial counts on normal healthy skin. The results were similar to Povidone-iodine alone. We believe this technology may be an excellent means of mitigating incisional surgical site infection by reducing the risk of contamination by skin flora and warrants further testing.

Potassium sorbate release from poly(vinyl alcohol)-bacterial cellulose films

2012 ◽  
Vol 66 (2) ◽  
Author(s):  
Iuliana Jipa ◽  
Anicuta Stoica ◽  
Marta Stroescu ◽  
Loredana-Mihaela Dobre ◽  
Tanase Dobre ◽  
...  
Keyword(s):  
Bacterial Cellulose ◽  
Antimicrobial Properties ◽  
Potassium Sorbate ◽  
Poly Vinyl Alcohol ◽  
Packaging Materials ◽  
Cellulose Powder ◽  
Cellulose Films ◽  
Antimicrobial Materials ◽  
Biocomposite Films ◽  
The Subject

AbstractActive packaging materials are the subject of research because their performance exceeds that of traditional packaging. From this class, antimicrobial materials extend the shelf-life of products and reduce the risk of contamination by pathogens. In this paper, new composite materials with antimicrobial properties are obtained by using polyvinyl alcohol and bacterial cellulose powder. Potassium (2E,4E)-hexa-2,4-dienoate was used as the antimicrobial agent. The films thus obtained were characterised using Fourier-transform infrared spectroscopy and scanning electron microscopy. Mass transfer phenomena concerning the release of potassium (2E,4E)-hexa-2,4-dienoate were investigated. The results indicated that the new biocomposite films could be used as antimicrobial packaging materials.

scholarly journals Polyaspartamide Functionalized Catechol-Based Hydrogels Embedded with Silver Nanoparticles for Antimicrobial Properties

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1188 ◽  
Author(s):  
Milène Tan ◽  
Youngjin Choi ◽  
Jaeyun Kim ◽  
Ji-Heung Kim ◽  
Katharina Fromm
Keyword(s):  
Antimicrobial Properties ◽  
Kinetic Studies ◽  
Bactericidal Effect ◽  
Release Kinetic ◽  
E Coli ◽  
Dispersed Particles ◽  
Time Period ◽  
Long Time ◽  
20 Nm

In this study, polyaspartamide-based hydrogels were synthesized by boron-catechol coordination followed by incorporation of AgNPs into the materials. Free catechol moieties were exploited to produce AgNPs. TEM analyses displayed AgNPs of less than 20 nm in diameter and with minimum aggregation, attesting the role of hydrogels to act as an efficient template for the production of dispersed particles. XRD analyses confirmed the mean particle size using the Scherrer equation. Release kinetic studies were performed in DMEM medium, showing a slow release over a long time-period. Finally, the MIC and MBC were determined, demonstrating a bacteriostatic and bactericidal effect against Gram-positive S. aureus and Gram-negative E. coli.

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