Use of Cold Plasma To Inactivate Escherichia coli and Physicochemical Evaluation in Pumpkin Puree

2018 ◽  
Vol 81 (11) ◽  
pp. 1897-1905 ◽  
Author(s):  
L. C. O. SANTOS ◽  
A. L. V. CUBAS ◽  
E. H. S. MOECKE ◽  
D. H. B. RIBEIRO ◽  
E. R. AMANTE
Keyword(s):  
Escherichia Coli ◽  
Corona Discharge ◽  
Cold Plasma ◽  
Treatment Time ◽  
Physicochemical Characteristics ◽  
Carotenoid Content ◽  
E Coli ◽  
Process Gas ◽  
Total Carotenoid Content ◽  
Plasma Corona

ABSTRACT This work aimed to study the pumpkin puree processing by cold plasma corona discharge as an alternative to heat treatment to reduce Escherichia coli contamination and evaluate physicochemical alterations, using argon (Ar) as the process gas. The treatment time to verify E. coli inactivation was between 2 and 20 min, while physicochemical alterations were analyzed at 5, 10, 15, and 20 min. Cold plasma corona discharge technology to inactivate E. coli proved to be promising, reaching 3.62 log cycles of reduction at 20 min of treatment. The inactivation kinectics showed a tendency of higher decrease with time. Physicochemical characteristics indicate that plasma induces a decrease of pH; however, there is an indication that process gases have an important role and react with the environment and procedure reactive species. This technology may reduce the total carotenoid content of pumpkin puree and in color, mainly the a* parameter, which showed great reduction.

Inactivation of Escherichia coli by Ultrasound Combined with Nisin

2018 ◽  
Vol 81 (6) ◽  
pp. 993-1000 ◽  
Author(s):  
ZUWEN WANG ◽  
XIUFANG BI ◽  
RUI XIANG ◽  
LIYI CHEN ◽  
XIAOPING FENG ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Synergistic Effect ◽  
Linear Models ◽  
Treatment Time ◽  
Nutrient Broth ◽  
Inactivation Kinetics ◽  
Growth Phases ◽  
E Coli ◽  
Kinetics Of ◽  
Inactivation Effect

ABSTRACT The aim of this study was to investigate the inactivation of nonpathogenic Escherichia coli in nutrient broth and milk through the use of either ultrasound (US) alone or US combined with nisin (US + nisin) treatments. The E. coli cells were treated at 0 to 55°C, 242.04 to 968.16 W/cm2 for 0 to 15 min. The results showed that the inactivation of E. coli by US and US + nisin increased when the temperature, US power density, and treatment time were increased. The inactivation kinetics of E. coli in nutrient broth by US and US + nisin both conformed to linear models. The largest reductions of 2.89 and 2.93 log cycles by US and US + nisin, respectively, were achieved at 968.16 W/cm2 and at 25°C for 15 min. The suspension media of the E. coli cells influenced the inactivation effect of US, while the growth phases of E. coli cells did not affect their resistance to US. Under all experiment conditions of this study, the differences between US and US + nisin in their respective inactivation effects on E. coli were not obvious. The results suggested that nisin had either no effect at all or a weak synergistic effect with US and that the E. coli cells were inactivated mainly by US, thus indicating that the inactivation of E. coli by US is an “all or nothing” event.

Ammonia sanitization of blackwater for safe use as fertilizer

2015 ◽  
Vol 71 (5) ◽  
pp. 795-800 ◽  
Author(s):  
Jörgen Fidjeland ◽  
Sven-Erik Svensson ◽  
Björn Vinnerås
Keyword(s):  
Escherichia Coli ◽  
Treatment Time ◽  
Escherichia Coli O157 ◽  
Storage Facility ◽  
Egg Viability ◽  
Pathogen Inactivation ◽  
E Coli ◽  
Available Nutrients ◽  
Manure Slurry ◽  
The Impact

Source-separated blackwater from low-flush toilets contains plant-available nutrients and can be used as a fertilizer. The aim of the study was to evaluate the impact on pathogen inactivation when treating blackwater with urea and/or lime. Blackwater was spiked with Salmonella typhimurium, Escherichia coli O157, Enterococcus faecalis, and Ascaris suum eggs, and treated with urea and/or lime in concentrations up to 0.1% w/w. The bottles were kept in a storage facility (manure slurry tank) for 102 days while monitoring the pathogen concentrations. The treatment time needed to meet the requirement for Salmonella and E. coli reduction could be reduced at least six-fold. The enterococci were more persistent, and only the highest treatment doses had a significantly higher inactivation than the controls. The Ascaris egg viability was only reduced by around 50%, so higher urea/lime doses and/or longer treatment times are required to fulfill the treatment requirements of 3 log10 reductions of parasite eggs.

scholarly journals Mechanisms of Inactivation by High-Voltage Atmospheric Cold Plasma Differ for Escherichia coli and Staphylococcus aureus

2015 ◽  
Vol 82 (2) ◽  
pp. 450-458 ◽  
Author(s):  
L. Han ◽  
S. Patil ◽  
D. Boehm ◽  
V. Milosavljević ◽  
P. J. Cullen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
High Voltage ◽  
Dna Cleavage ◽  
Cold Plasma ◽  
Treatment Time ◽  
Enzyme Inactivation ◽  
Content Type ◽  
Intracellular Ros ◽  
Wide Range

ABSTRACTAtmospheric cold plasma (ACP) is a promising nonthermal technology effective against a wide range of pathogenic microorganisms. Reactive oxygen species (ROS) play a crucial inactivation role when air or other oxygen-containing gases are used. With strong oxidative stress, cells can be damaged by lipid peroxidation, enzyme inactivation, and DNA cleavage. Identification of ROS and an understanding of their role are important for advancing ACP applications for a range of complex microbiological issues. In this study, the inactivation efficacy of in-package high-voltage (80 kV [root mean square]) ACP (HVACP) and the role of intracellular ROS were investigated. Two mechanisms of inactivation were observed in which reactive species were found to either react primarily with the cell envelope or damage intracellular components.Escherichia coliwas inactivated mainly by cell leakage and low-level DNA damage. Conversely,Staphylococcus aureuswas mainly inactivated by intracellular damage, with significantly higher levels of intracellular ROS observed and little envelope damage. However, for both bacteria studied, increasing treatment time had a positive effect on the intracellular ROS levels generated.

Response Surface Modeling for the Inactivation of Escherichia coli O157:H7 on Green Peppers (Capsicum annuum L.) by Chlorine Dioxide Gas Treatments†

2001 ◽  
Vol 64 (8) ◽  
pp. 1128-1133 ◽  
Author(s):  
Y. HAN ◽  
J. D. FLOROS ◽  
R. H. LINTON ◽  
S. S. NIELSEN ◽  
P. E. NELSON
Keyword(s):  
Escherichia Coli ◽  
Predictive Model ◽  
Response Surface ◽  
Chlorine Dioxide ◽  
Treatment Time ◽  
Membrane Surface ◽  
Escherichia Coli O157 ◽  
Gas Concentration ◽  
E Coli ◽  
Log Reduction

The effects of chlorine dioxide (ClO2) gas concentration (0.1 to 0.5 mg/liter), relative humidity (RH) (55 to 95%), treatment time (7 to 135 min), and temperature (5 to 25°C) on inactivation of Escherichia coli O157:H7 on green peppers were studied using response surface methods. A four-factor, central, composite, rotatable design was used. The microbial log reduction was measured as a response. A direct membrane-surface-plating method with tryptic soy agar and sorbitol Mac-Conkey agar was used to resuscitate and enumerate ClO2-treated E. coli O157:H7 cells. The statistical analysis and the predictive model developed in this study suggest that ClO2 gas concentration, treatment time, RH, and temperature all significantly (P < 0.01) increased the inactivation of E. coli O157:H7. ClO2 gas concentration was the most important factor, whereas temperature was the least significant. The interaction between ClO2 gas concentration and RH indicated a synergistic effect. The predictive model was validated, and it could be used to determine effective ClO2 gas treatments to achieve a 5-log reduction of E. coli O157:H7 on green peppers.

Cold Plasma Inactivates Salmonella Stanley and Escherichia coli O157:H7 Inoculated on Golden Delicious Apples†

2008 ◽  
Vol 71 (7) ◽  
pp. 1357-1365 ◽  
Author(s):  
BRENDAN A. NIEMIRA ◽  
JOSEPH SITES
Keyword(s):  
Escherichia Coli ◽  
Exposure Time ◽  
Cold Plasma ◽  
Treatment Time ◽  
Limit Of Detection ◽  
Maximum Temperature ◽  
Escherichia Coli O157 ◽  
Flow Rates ◽  
Lower Flow ◽  
Golden Delicious

Cold plasma generated in a gliding arc was applied to outbreak strains of Escherichia coli O157:H7 and Salmonella Stanley on agar plates and inoculated onto the surfaces of Golden Delicious apples. This novel sanitizing technology inactivated both pathogens on agar plates, with higher flow rate (40 liters/min) observed to be more efficacious than were lower flow rates (20 liters/min), irrespective of treatment time (1 or 2 min). Golden Delicious apples were treated with various flow rates (10, 20, 30, or 40 liters/min) of cold plasma for various times (1, 2, or 3 min), applied to dried spot inoculations. All treatments resulted in significant (P < 0.05) reductions from the untreated control, with 40 liters/min more effective than were lower flow rates. Inactivation of Salmonella Stanley followed a time-dependent reduction for all flow rates. Reductions after 3 min ranged from 2.9 to 3.7 log CFU/ml, close to the limit of detection. For E. coli O157:H7, 40 liters/min gave similar reductions for all treatment times, 3.4 to 3.6 log CFU/ml. At lower flow rates, inactivation was related to exposure time, with 3 min resulting in reductions of 2.6 to 3 log CFU/ml. Temperature increase of the treated apples was related to exposure time for all flow rates. The maximum temperature of any plasma-treated apple was 50.8°C (28°C above ambient), after 20 liters/min for 3 min, indicating that antimicrobial effects were not the result of heat. These results indicate that cold plasma is a nonthermal process that can effectively reduce human pathogens inoculated onto fresh produce.

Inactivation of Listeria innocua, Salmonella Typhimurium, and Escherichia coli O157:H7 on Surface and Stem Scar Areas of Tomatoes Using In-Package Ozonation†

2012 ◽  
Vol 75 (9) ◽  
pp. 1611-1618 ◽  
Author(s):  
XUETONG FAN ◽  
KIMBERLY J. B. SOKORAI ◽  
JÜRGEN ENGEMANN ◽  
JOSHUA B. GURTLER ◽  
YANHONG LIU
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Treatment Time ◽  
Listeria Innocua ◽  
Escherichia Coli O157 ◽  
Bacterial Reduction ◽  
Negative Effects ◽  
E Coli ◽  
Storage Study ◽  
Proportional Increase

A novel in-package ozonation device was evaluated for its efficacy in inactivating three microorganisms (viz., Listeria innocua, attenuated Salmonella Typhimurium, and Escherichia coli O157:H7) on tomatoes and for its effect on fruit quality. The device produced ozone inside sealed film bags, reaching a concentration of 1,000 ppm within 1 min of activation. The three bacterial cultures were inoculated onto either the smooth surface or the stem scar areas of the tomatoes, which were then sealed in plastic film bags and subjected to in-package ozonation. L. innocua on tomatoes was reduced to nondetectable levels within 40 s of treatment on the tomato surface, with inactivation of ca. 4 log CFU per fruit on the stem scar area. An increase in treatment time did not result in a proportional increase in bacterial reduction. For E. coli O157:H7 and Salmonella, there was little difference (<1 log) in the effectiveness of the system when comparing surface and scar-inoculated bacteria. Both bacteria were typically reduced by 2 to 3 log CFU per fruit after 2- to 3-min treatments. No negative effects on fruit color or texture were observed during a 22-day posttreatment storage study of ozone-treated tomatoes. These results suggest that the three bacteria responded differently to ozonation and that in-package ozonation may provide an alternative to chemical sanitizers commonly used by the industry.

scholarly journals Effects of Atmospheric Plasma Corona Discharge on Agrobacterium tumefaciens Survival

2021 ◽  
Vol 10 (1) ◽  
pp. 32
Author(s):  
Yulia Lazra ◽  
Bharath Gandu ◽  
Irina Dubrovin Amar ◽  
Efrat Emanuel ◽  
Rivka Cahan
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Corona Discharge ◽  
Membrane Permeability ◽  
Cell Size ◽  
Cold Plasma ◽  
Bacterial Eradication ◽  
Liquid Environment ◽  
Initial Concentration ◽  
Plasma Corona ◽  
The Impact

Soil-borne pathogenic microorganisms are known to cause extensive crop losses. Agrobacterium tumefaciens, a member of the Proteobacteria, causes the neoplastic crown gall disease in plants. Plant protection is mainly based on toxic chemicals that are harmful to the environment. The use of cold atmospheric-pressure plasma is an attractive method for microbial eradication. Its antimicrobial mechanism includes the formation of large quantities of reactive oxygen species (ROS). The advantages of eradicating bacteria using cold plasma are not needed for chemicals, short treatment, and environmental temperatures. This study examined the impact of plasma corona discharge exposure on A. tumefaciens viability, membrane permeability, relative cell size, and ROS formation. The results showed that 90 s of plasma exposure led to a reduction by four orders of magnitude when the initial concentration was 1 × 107 CFU/mL and in a dry environment. When the initial concentration was 1 × 106 CFU/mL, 45 s of exposure resulted in total bacterial eradication. In a liquid environment, in an initial concentration of 2.02 × 106 CFU/mL, there was no complete bacterial eradication even at the most prolonged examined exposure (90 s). The influence of plasma treatment on the membrane permeability of A. tumefaciens, and their possible recovery, were analyzed using flow cytometer analysis using propidium iodide (PI). When the plasma-treated bacteria were suspended in Luria–Bertani (LB) (rich medium), the PI-positive count of the plasma-treated bacteria after two hours was 12 ± 3.9%. At the 24th hour, this percentage was only 1.74 ± 0.6%, as the control (0.7 ± 0.1%). These results may indicate the repair of the plasma-treated bacteria that were suspended in LB. At the 24th hour, the relative cell size of the treated bacteria shifted to the right, to ~3 × 104 forward side scatter (FSC), about 0.5-fold higher than the untreated cells. Measurement of the ROS showed that the intracellular fluorescence of the 90-s plasma-treated cells led to significant fluorescence formation of 32 relative fluorescence units (RFU)/cell (9 × 104 fold, compared to the nontreated cells). This study showed that cold plasma is a useful method for A. tumefaciens eradication. The eradication mechanism involves ROS generation, membrane permeability, and changes in cell size.

scholarly journals COMBINING MODERATE PULSED ELECTRIC FIELDS WITH TEMPERATURE AND WITH ORGANIC ACIDS TO INACTIVATE ESCHERICHIA COLI SUSPENSIONS

2010 ◽  
Vol 9 (1) ◽  
pp. 1-8
Author(s):  
Henri EL ZAKHEM ◽  
Jean-Louis LANOISELLE ◽  
Nikolai LEBOVKA ◽  
Maurice NONUS ◽  
Hind ALLALI ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Electric Field ◽  
Organic Acids ◽  
Electric Fields ◽  
Treatment Time ◽  
Inactivation Kinetics ◽  
Thermal Treatments ◽  
Medium Temperature ◽  
E Coli ◽  
Aqueous Suspensions

The aim of this work was to study the efficiency of inactivation of Escherichia coli cells in aqueous suspensions using combined moderate pulsed electric field (PEF) and thermal treatments. The inactivation kinetics of E. coli cells in aqueous suspensions (1 wt%) was monitored using conductometric technique. The electric field strength E was within 5-7.5 kV/cm, the effective PEF treatment time was within 0-0.75 s, the pulse duration ti was within 0.3-1 ms, the medium temperature was 30-50°C, and the time of thermal treatment tT was within 0-7000 s. The organic acid concentration was within 0-0.5 g/L.The damage of E. coli was accompanied by release of intracellular components. The synergy between the PEF and thermal treatments in E. coli inactivation was clearly demonstrated. The damage efficiency was noticeably improved by addition of organic acids, especially lactic acid.

Microbial Inactivation and Physicochemical Properties of Ultrasound Processed Pomegranate Juice

2015 ◽  
Vol 78 (3) ◽  
pp. 531-539 ◽  
Author(s):  
ÇİĞDEM UYSAL PALA ◽  
NÜKHET NİLÜFER DEMIREL ZORBA ◽  
GÜLÇİN ÖZCAN
Keyword(s):  
Total Phenolics ◽  
Treatment Time ◽  
Color Difference ◽  
Physicochemical Characteristics ◽  
Microbial Inactivation ◽  
Ultrasound Treatment ◽  
Soluble Solids ◽  
Pomegranate Juice ◽  
E Coli ◽  
Log Linear

The effects of ultrasound treatment at various amplitudes (50, 75, and 100%) and times (0, 6, 12, 18, 24, and 30 min) on Escherichia coli ATCC 25922 (a surrogate for E. coli O157:H7) and Saccharomyces cerevisiae ATCC 2366 levels and physicochemical characteristics (monomeric anthocyanins, color values, total phenolics, pH, and soluble solids) were determined in pomegranate juice. More than a 5-log inactivation of E. coli ATCC 25922 and a 1.36-log inactivation of S. cerevisiae ATCC 2366 were achieved after 30 min of ultrasound treatment at 100%amplitude. The log-linear and Weibull models were successfully used to estimate the microbial inactivation as a function of ultrasound treatment time (R2 > 0.97). No significant changes were observed in total phenolics, pH, and soluble solids of the treated juice (P > 0.05). The ultrasound treatment for up to 30 min resulted in more than 92 and 89% anthocyanin retention at 75 and 100% amplitude, respectively. The redness (a*) of the juice did not change significantly after the ultrasound treatment at amplitudes of 75 and 100% for up to 24 and 12 min, respectively. No significant changes in L* and b* values were observed after ultrasound treatment at all amplitudes and after up to 30 min of treatment for 50 and 75% amplitudes. Small differences in juice color were noted based on total color difference scores.

scholarly journals Inactivation of Escherichia coli Cells in Aqueous Solution by Atmospheric-Pressure N2, He, Air, and O2Microplasmas

2015 ◽  
Vol 81 (15) ◽  
pp. 5257-5265 ◽  
Author(s):  
Renwu Zhou ◽  
Xianhui Zhang ◽  
Zhenhua Bi ◽  
Zichao Zong ◽  
Jinhai Niu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Aqueous Solution ◽  
Atmospheric Pressure ◽  
Reaction Rate ◽  
Treatment Time ◽  
Process Analysis ◽  
Content Type ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
Plasma Treatment Time

ABSTRACTAtmospheric-pressure N2, He, air, and O2microplasma arrays have been used to inactivateEscherichia colicells suspended in aqueous solution. Measurements show that the efficiency of inactivation ofE. colicells is strongly dependent on the feed gases used, the plasma treatment time, and the discharge power. Compared to atmospheric-pressure N2and He microplasma arrays, air and O2microplasma arrays may be utilized to more efficiently killE. colicells in aqueous solution. The efficiencies of inactivation ofE. colicells in water can be well described by using the chemical reaction rate model, where reactive oxygen species play a crucial role in the inactivation process. Analysis indicates that plasma-generated reactive species can react withE. colicells in water by direct or indirect interactions.

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