Inactivation of recalcitrant protozoan oocysts and bacterial endospores in drinking water using high-intensity pulsed UV light irradiation

2012 ◽  
Vol 12 (4) ◽  
pp. 513-522 ◽  
Author(s):  
J. C. Hayes ◽  
M. Garvey ◽  
A. M. Fogarty ◽  
E. Clifford ◽  
N. J. Rowan
Keyword(s):  
High Intensity ◽  
Uv Light ◽  
Waste Water Treatment ◽  
Scale Up ◽  
Clear Trend ◽  
E Coli ◽  
Log Reduction ◽  
Bacterial Endospores ◽  
Pulsed Uv Light ◽  
Uv Dose

This constitutes the first study to compare the use of high-intensity pulsed UV light (PUV) irradiation for the novel destruction of harmful protozoan (Cryptosporidium parvum Iowa isolate) oocysts and bacterial (Clostridium perfringens ATCC 13124 and Bacillus cereus ATCC 11178) endospores in artificially-spiked water where these organisms are resistant to conventional chlorination. Experimental results revealed that all three test organisms in their dormant recalcitrant state required extended levels of pulsing to achieve significant reductions in numbers compared to other similarly PUV-treated Escherichia coli ATCC 25922 that is a non-spore forming indicator of faecal pollution in water. 120 pulses at 900 V or 16.2 J per pulse (equivalent to a UV dose of 8.39 μJ cm−2) were required to achieve ca. 2 log C. perfringens spore numbers, whereas a similar level of PUV irradiation reduced both C. parvum oocysts and B. cereus endospores by ca. 5 log orders. A comparative ca. 5 log reduction of E. coli cell numbers was achieved after only 25 pulses at 900 V (equivalent to a UV dose of 1.74 μJ cm−2). A clear trend emerged where the order of resistance to PUV-irradiation observed was C. perfringens endospores > C. parvum oocysts, B. cereus endospores > E. coli cells. This study suggests disinfection kinetic data for the more resistant C. perfringens endospores can be used as a measure of estimating disinfection efficacy of PUV treatments for C. parvum oocysts in water, avoiding the need to use complex animal or cell culture infectivity models that are only available in specialised laboratories with highly trained technicians. This study will inform future studies exploring scale-up of PUV at waste-water treatment plants.

Apple Juice Preservation Using Combined Nonthermal Processing and Antimicrobial Packaging

2021 ◽  
Author(s):  
Tony Jin ◽  
RAMADAN M. ABOELHAGGAG ◽  
Mingming Guo
Keyword(s):  
Electric Fields ◽  
Apple Juice ◽  
Uv Light ◽  
Antimicrobial Packaging ◽  
E Coli ◽  
Log Reduction ◽  
Nonthermal Processing ◽  
Soluble Solid ◽  
Pulsed Uv Light ◽  
Mold And Yeast

This study investigated the effectiveness of pulsed electric fields (PEF) treatment (19, 23, 30 kV/cm), pulsed UV light (PL) treatment (5 to 50 s; 1.04 J/cm 2 /s), and antimicrobial packaging (AP) treatment, either individually or combined, in inactivating bacteria and in maintaining the quality of fruit juices. Apple juice samples, inoculated with Escherichia coli K12 or native mold and yeast (M&Y), were treated by a bench scale PEF and/or PL processing systems and stored in glass jars with antimicrobial caps containing 10 µl of carvacrol (AP). The reduction in microbial populations and the physicochemical properties of juice samples were determined after treatments and during storage at 10°C. The treatments included PL (5 to 50 s; 1.04 J/cm 2 /s ), PEF (19, 23, 30 kV/cm), PEF followed by PL (PEF+PL), PL followed by PEF (PL+PEF), and PEF+PL+AP. PEF treatments from 19 to 30 kV/cm (PEF19, PEF23, PEF30) achieved E. coli reduction by 2.0, 2.6 and 4.0 log CFU/ml, respectively; PL treatments for 10 to 50 seconds (PL10, PL20, PL30, PL40, PL50) achieved E. coli reduction by 0.45, 0.67, 0.76, 2.3, and 4.0 log CFU/ml, respectively. There were no significant (p>0.05) differences between the combined PL20+PEF19 and PEF19+PL20 treatments; both treatments reduced E. coli K12 populations to non-detectable levels (> 5 log reduction) after 7 days. Both PEF+PL and PEF+PL+AP treatments achieved over 5 log reduction of M&Y; however, juice samples subject to PEF+PL+AP treatment had lower M&Y counts (2.9 log) than samples subject to PEF+PL treatment (3.9 log) after 7 days. There were no significant (p > 0.05) differences in pH, acidity, total soluble solid contents among all samples after treatments. Increased PL treatment times reduced color a*, b* values, total phenolics and carotenoid contents. This study provides valuable information to juice processors for consideration and design of nonthermal pasteurization of juice products.

Modeling of Escherichia coli Inactivation by UV Irradiation at Different pH Values in Apple Cider

2004 ◽  
Vol 67 (6) ◽  
pp. 1153-1156 ◽  
Author(s):  
A. QUINTERO-RAMOS ◽  
J. J. CHUREY ◽  
P. HARTMAN ◽  
J. BARNARD ◽  
R. W. WOROBO
Keyword(s):  
Escherichia Coli ◽  
Uv Irradiation ◽  
Uv Light ◽  
Reduction Factor ◽  
Attractive Alternative ◽  
Bacterial Populations ◽  
Apple Cider ◽  
E Coli ◽  
Log Reduction ◽  
Uv Dose

This study examined the effects and interactions of UV light dose (1,800 to 20,331 μJ/cm2) and apple cider pH (2.99 to 4.41) on the inactivation of Escherichia coli ATCC 25922, a surrogate for E. coli O157:H7. A predictive model was developed to relate the log reduction factor of E. coli ATCC 25922 to the UV dose. Bacterial populations for treated and untreated samples were enumerated with the use of nonselective media. The results revealed that UV dose was highly significant in the inactivation of E. coli, whereas pH showed no significant effect at higher UV doses. Doses of 6,500 μJ/cm2 or more were sufficient to achieve a greater than 5-log reduction of E. coli. Experimental inactivation data were fitted adequately by a logistic regression model. UV irradiation is an attractive alternative to conventional methods for reducing bacteria in unpasteurized apple cider.

scholarly journals VOC Removal from Manure Gaseous Emissions with UV Photolysis and UV-TiO2 Photocatalysis

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 607 ◽  
Author(s):  
Xiuyan Yang ◽  
Jacek A. Koziel ◽  
Yael Laor ◽  
Wenda Zhu ◽  
J. (Hans) van Leeuwen ◽  
...  
Keyword(s):  
Treatment Effectiveness ◽  
Uv Light ◽  
Scale Up ◽  
Poultry Manure ◽  
Primary Treatment ◽  
Gaseous Emissions ◽  
Odor Removal ◽  
Odor Emissions ◽  
Livestock Odor ◽  
Uv Dose

Control of gaseous emissions from livestock operations is needed to ensure compliance with environmental regulations and sustainability of the industry. The focus of this research was to mitigate livestock odor emissions with UV light. Effects of the UV dose, wavelength, TiO2 catalyst, air temperature, and relative humidity were tested at lab scale on a synthetic mixture of nine odorous volatile organic compounds (VOCs) and real poultry manure offgas. Results show that it was feasible to control odorous VOCs with both photolysis and photocatalysis (synthetic VOCs mixture) and with photocatalysis (manure offgas). The treatment effectiveness R (defined as % conversion), was proportional to the light intensity for synthetic VOCs mixtures and followed an order of UV185+254 + TiO2 > UV254 + TiO2 > UV185+254; no catalyst > UV254; no catalyst. VOC conversion R > 80% was achieved when light energy was >~60 J L−1. The use of deep UV (UV185+254) improved the R, particularly when photolysis was the primary treatment. Odor removal up to ~80% was also observed for a synthetic VOCs mixture, and actual poultry manure offgas. Scale-up studies are warranted.

Efficacy of Ultraviolet Light for Reducing Escherichia coli O157:H7 in Unpasteurized Apple Cider

2000 ◽  
Vol 63 (5) ◽  
pp. 563-567 ◽  
Author(s):  
J. R. WRIGHT ◽  
S. S. SUMNER ◽  
C. R. HACKNEY ◽  
M. D. PIERSON ◽  
B. W. ZOECKLEIN
Keyword(s):  
Thin Film ◽  
Escherichia Coli ◽  
Uv Light ◽  
Uv Disinfection ◽  
Escherichia Coli O157 ◽  
Apple Cider ◽  
E Coli ◽  
Log Reduction ◽  
Disinfection Unit ◽  
Additional Reduction

This study examined the efficacy of UV light for reducing Escherichia coli O157:H7 in unpasteurized cider. Cider containing a mixture of acid-resistant E. coli O157:H7 (6.3 log CFU/ml) was treated using a thin-film UV disinfection unit at 254 nm. Dosages ranged from 9,402 to 61,005 μW-s/cm2. Treatment significantly reduced E. coli O157:H7 (P ≤ 0.0001). Mean reduction for all treated samples was 3.81 log CFU/ml. Reduction was also affected by the level of background microflora in cider. Results indicate that UV light is effective for reducing this pathogen in cider. However, with the dosages used in this experiment, additional reduction measures are necessary to achieve the required 5-log reduction.

Pulsed UV Light Inactivation of Salmonella Enteritidis on Eggshells and Its Effects on Egg Quality

2010 ◽  
Vol 73 (8) ◽  
pp. 1408-1415 ◽  
Author(s):  
NENE M. KEKLIK ◽  
ALI DEMIRCI ◽  
PAUL H. PATTERSON ◽  
VIRENDRA M. PURI
Keyword(s):  
Salmonella Enteritidis ◽  
Egg Quality ◽  
Uv Light ◽  
Detergent Solution ◽  
Department Of Agriculture ◽  
The Public ◽  
Log Reduction ◽  
Visual Damage ◽  
Pulsed Uv Light ◽  
Uv Lamp

The majority of Salmonella Enteritidis outbreaks have been related to the consumption of raw or undercooked eggs or egg-containing foods. Therefore, the U.S. Department of Agriculture mandates egg washing for all graded eggs by use of a detergent solution and sanitizer. These agencies and the egg industry have been investigating alternative decontamination techniques, which could better serve the public, minimize costs, and benefit both the public and the industry. Pulsed UV light is an emerging technology that is used to inactivate microorganisms quickly. In this study, the effectiveness of pulsed UV light was evaluated for the decontamination of eggshells. Eggs inoculated with Salmonella Enteritidis on the top surface at the equator were treated with pulsed UV light 1 to 30 s, at a distance of 9.5 and 14.5 cm from the UV lamp in a laboratory-scale, pulsed UV light chamber. Three eggs were used per treatment in each repetition, except for quality measurements, which involved six eggs per treatment in each repetition. A maximum log reduction of 5.3 CFU/cm2 was obtained after a 20-s treatment at 9.5 cm below the UV lamp at a total dose of 23.6 ± 0.1 J/cm2, without any visual damage to the egg. After a 30-s treatment at 9.5 and 14.5 cm, the temperature of eggshell surfaces increased by 16.3 and 13.3°C, respectively. Energy usage increased up to 35.3 ± 0.1 and 24.8 ± 0.1 J/cm2, after 30-s treatments at 9.5 and 14.5 cm, respectively. The effect of pulsed UV light treatments on egg quality was also evaluated. Pulsed UV-light treatments for 3, 10, and 20 s at either 9.5 or 14.5 cm did not change the albumen height, eggshell strength, or cuticle presence significantly (P > 0.05). This study demonstrated that pulsed UV light has potential to decontaminate eggshell surfaces.

Efficient Reduction of Pathogenic and Spoilage Microorganisms from Apple Cider by Combining Microfiltration with UV Treatment

2015 ◽  
Vol 78 (4) ◽  
pp. 716-722 ◽  
Author(s):  
DONGJUN ZHAO ◽  
JESSIE USAGA BARRIENTOS ◽  
QING WANG ◽  
SARAH M. MARKLAND ◽  
JOHN J. CHUREY ◽  
...  
Keyword(s):  
Pore Size ◽  
Ceramic Membranes ◽  
Transmembrane Pressure ◽  
Uv Treatment ◽  
Apple Cider ◽  
E Coli ◽  
Log Reduction ◽  
Off Flavors ◽  
Uv Dose ◽  
Thermal Pasteurization

Thermal pasteurization can achieve the U.S. Food and Drug Administration–required 5-log reduction of pathogenic Escherichia coli O157:H7 and Cryptosporidium parvum in apple juice and cider, but it can also negatively affect the nutritional and organoleptic properties of the treated products. In addition, thermal pasteurization is only marginally effective against the acidophilic, thermophilic, and spore-forming bacteria Alicyclobacillus spp., which is known to cause off-flavors in juice products. In this study, the efficiency of a combined microfiltration (MF) and UV process as a nonthermal treatment for the reduction of pathogenic and nonpathogenic E. coli, C. parvum, and Alicyclobacillus acidoterrestris from apple cider was investigated. MF was used to physically remove suspended solids and microorganisms from apple cider, thus enhancing the effectiveness of UV and allowing a lower UV dose to be used. MF, with ceramic membranes (pore sizes, 0.8 and 1.4 μm), was performed at a temperature of 10°C and a transmembrane pressure of 155 kPa. The subsequent UV treatment was conducted using at a low UV dose of 1.75 mJ/cm2. The combined MF and UV achieved more than a 5-log reduction of E. coli, C. parvum, and A. acidoterrestris. MF with the 0.8-μm pore size performed better than the 1.4-μm pore size on removal of E. coli and A. acidoterrestris. The developed nonthermal hurdle treatment has the potential to significantly reduce pathogens, as well as spores, yeasts, molds, and protozoa in apple cider, and thus help juice processors improve the safety and quality of their products.

scholarly journals A pulsed light system for the disinfection of flow through water in the presence of inorganic contaminants

2014 ◽  
Vol 13 (2) ◽  
pp. 406-412 ◽  
Author(s):  
Mary Garvey ◽  
Neil Rowan
Keyword(s):  
Uv Light ◽  
Water Disinfection ◽  
Bacterial Cells ◽  
Limited Data ◽  
Inorganic Contaminants ◽  
Test Species ◽  
Bacterial Endospores ◽  
Effective Form ◽  
Pulsed Uv Light ◽  
Flow Through

The use of ultraviolet (UV) light for water disinfection has become increasingly popular due to on-going issues with drinking water and public health. Pulsed UV light has proved to be an effective form of inactivating a range of pathogens including parasite species. However, there are limited data available on the use of pulsed UV light for the disinfection of flowing water in the absence or presence of inorganic contaminants commonly found in water sources. Here, we report on the inactivation of test species including Bacillus endospores following pulsed UV treatment as a flow through system. Significant levels of inactivation were obtained for both retention times tested. The presence of inorganic contaminants iron and/or manganese did affect the rate of disinfection, predominantly resulting in an increase in the levels of inactivation at certain UV doses. The findings of this study suggest that pulsed UV light may provide a method of water disinfection as it successfully inactivated bacterial cells and bacterial endospores in the absence and presence of inorganic contaminants.

Efficacy of UV Light for the Reduction of Listeria monocytogenes in Goat's Milk

2005 ◽  
Vol 68 (10) ◽  
pp. 2212-2216 ◽  
Author(s):  
K. E. MATAK ◽  
J. J. CHUREY ◽  
R. W. WOROBO ◽  
S. S. SUMNER ◽  
E. HOVINGH ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Uv Light ◽  
Dose Range ◽  
Federal Regulations ◽  
Milk Products ◽  
Log Reduction ◽  
Goat’S Milk ◽  
Unpasteurized Milk ◽  
Goat's Milk ◽  
Uv Dose

Certain types of goat's cheeses are produced using unpasteurized milk, which increases the food safety concerns for these types of products. Popularity and consumption of goat's milk products have increased, and the niche market includes gourmet goat's cheeses. The U.S. Code of Federal Regulations and the Pasteurized Milk Ordinance both address the possibility for processing alternatives to heat treatment, and the use of UV light treatment may be a viable alternative that still ensures the safety of the product. Fresh goat's milk was inoculated with Listeria monocytogenes (L-2289) at 107 CFU/ml and exposed to UV light using the CiderSure 3500 apparatus (FPE Inc., Macedon, NY). Inoculated milk was exposed to a UV dose range between 0 and 20 mJ/cm2 to determine the optimal UV dose. A greater than 5-log reduction was achieved (P < 0.0001) when the milk received a cumulative UV dose of 15.8 ± 1.6 mJ/cm2. The results of this study indicate that UV irradiation could be used for the reduction of L. monocytogenes in goat's milk.

scholarly journals Pulsed Broad-Spectrum UV Light Effectively Inactivates SARS-CoV-2 on Multiple Surfaces and N95 Material

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 460
Author(s):  
Alexander S. Jureka ◽  
Caroline G. Williams ◽  
Christopher F. Basler
Keyword(s):  
Broad Spectrum ◽  
Uv Light ◽  
Public Spaces ◽  
Respiratory Viruses ◽  
Protective Equipment ◽  
Established Method ◽  
Effective Technology ◽  
Pulsed Uv Light ◽  
Uv Dose

The ongoing SARS-CoV-2 pandemic has resulted in an increased need for technologies capable of efficiently disinfecting public spaces as well as personal protective equipment. UV light disinfection is a well-established method for inactivating respiratory viruses. Here, we have determined that broad-spectrum, pulsed UV light is effective at inactivating SARS-CoV-2 on multiple surfaces in vitro. For hard, non-porous surfaces, we observed that SARS-CoV-2 was inactivated to undetectable levels on plastic and glass with a UV dose of 34.9 mJ/cm2 and stainless steel with a dose of 52.5 mJ/cm2. We also observed that broad-spectrum, pulsed UV light is effective at reducing SARS-CoV-2 on N95 respirator material to undetectable levels with a dose of 103 mJ/cm2. We included UV dosimeter cards that provide a colorimetric readout of UV dose and demonstrated their utility as a means to confirm desired levels of exposure were reached. Together, the results presented here demonstrate that broad-spectrum, pulsed UV light is an effective technology for the in vitro inactivation of SARS-CoV-2 on multiple surfaces.

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