Atmospheric Plasma Inactivation of Foodborne Pathogens on Fresh Produce Surfaces

2007 ◽  
Vol 70 (10) ◽  
pp. 2290-2296 ◽  
Author(s):  
FAITH J. CRITZER ◽  
KIMBERLY KELLY-WINTENBERG ◽  
SUZANNE L. SOUTH ◽  
DAVID A. GOLDEN
Keyword(s):  
Foodborne Pathogens ◽  
Tween 80 ◽  
Active Species ◽  
Atmospheric Plasma ◽  
Glow Discharge Plasma ◽  
Plasma Generation ◽  
E Coli ◽  
Log Reduction ◽  
Nonthermal Processing ◽  
Peptone Water

A study was conducted to determine the effect of one atmosphere uniform glow discharge plasma (OAUGDP) on inactivation of Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes on apples, cantaloupe, and lettuce, respectively. A five-strain mixture of cultured test organisms was washed, suspended in phosphate buffer, and spot inoculated onto produce (7 log CFU per sample). Samples were exposed inside a chamber affixed to the OAUGDP blower unit operated at a power of 9 kV and frequency of 6 kHz. This configuration allows the sample to be placed outside of the plasma generation unit while allowing airflow to carry the antimicrobial active species, including ozone and nitric oxide, onto the food sample. Cantaloupe and lettuce samples were exposed for 1, 3, and 5 min, while apple samples were exposed for 30 s, 1 min, and 2 min. After exposure, samples were pummeled in 0.1% peptone water–2% Tween 80, diluted, and plated in duplicate onto selective media and tryptic soy agar and incubated as follows: E. coli O157:H7 (modified eosin methylene blue) and Salmonella (xylose lysine tergitol-4) for 48 h at 37°C, and L. monocytogenes (modified Oxford medium) at 48 h for 32°C. E. coli O157: H7 populations were reduced by >1 log after 30-s and 1-min exposures and >2 log after a 2-min exposure. Salmonella populations were reduced by >2 log after 1 min. Three- and 5-min exposure times resulted in >3-log reduction. L. monocytogenes populations were reduced by 1 log after 1 min of exposure. Three- and 5-min exposure times resulted in >3- and >5-log reductions, respectively. This process has the capability of serving as a novel, nonthermal processing technology to be used for reducing microbial populations on produce surfaces.

scholarly journals Critical Synergistic Concentration of Lecithin Phospholipids Improves the Antimicrobial Activity of Eugenol against Escherichia coli

2017 ◽  
Vol 83 (21) ◽  
Author(s):  
Haoshu Zhang ◽  
Edward G. Dudley ◽  
Federico Harte
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Rational Design ◽  
Microbial Population ◽  
Critical Concentration ◽  
Antimicrobial Properties ◽  
Content Type ◽  
E Coli ◽  
Log Reduction ◽  
Naturally Occurring

ABSTRACT In this study, the effect of individual lecithin phospholipids on the antimicrobial properties of eugenol against Escherichia coli C600 was investigated. We tested five major phospholipids common in soy or egg lecithin (1,2-dihexadecanoyl-sn-glycero-3-phosphocholine [DPPC], 1,2-dioctadecanoyl-sn-glycero-3-phosphocholine [DSPC], 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine [DPPE], 1,2-dihexadecanoyl-sn-glycero-3-phosphate [sodium salt] [DPPA], and 1,2-dihexadecanoyl-sn-glycero-3-phospho-l-serine [DPPS]) and one synthetic cationic phospholipid (1,2-dioctadecanoyl-sn-glycero-3-ethylphosphocholine [18:0 EPC]). Among the six phospholipids, DPPC, DSPC, DPPE, DPPA, and the cationic 18:0 EPC showed critical synergistic concentrations that significantly improved the inactivation effect of eugenol against E. coli after 30 min of exposure. At the critical synergistic concentration, an additional ca. 0.4 to 1.9 log reduction (ca. 0.66 to 2.17 log CFU/ml reduction) in the microbial population was observed compared to eugenol-only (control) treatments (ca. 0.25 log reduction). In all cases, increasing the phospholipid amount above the critical synergistic concentration (which was different for each phospholipid) resulted in antimicrobial properties similar to those seen with the eugenol-only (control) treatments. DPPS did not affect the antimicrobial properties of eugenol at the tested concentrations. The critical synergistic concentration of phospholipids was correlated with their critical micelle concentrations (CMC). IMPORTANCE Essential oils (EOs) are naturally occurring antimicrobials, with limited use in food due to their hydrophobicity and strong aroma. Lecithin is used as a natural emulsifier to stabilize EOs in aqueous systems. We previously demonstrated that, within a narrow critical-concentration window, lecithin can synergistically enhance the antimicrobial properties of eugenol. Since lecithin is a mixture of different phospholipids, we aimed to identify which phospholipids are crucial for the observed synergistic effect. This research studied the bioactivity of lecithin phospholipids, contributing to a rational design in using lecithin to effectively control foodborne pathogens in foods.

High pressure processing of apple juice: the most effective parameters to inactivate pathogens of reference

2020 ◽  
Vol 122 (12) ◽  
pp. 3969-3979 ◽  
Author(s):  
Rodrigo Rodrigues Petrus ◽  
John Joseph Churey ◽  
Randy William Worobo
Keyword(s):  
High Pressure ◽  
Foodborne Pathogens ◽  
Apple Juice ◽  
High Pressure Processing ◽  
Effective Parameters ◽  
Content Type ◽  
E Coli ◽  
Log Reduction ◽  
Save Energy ◽  
Practical Implications

PurposeHigh-acid liquid foods are a substrate in which foodborne pathogens can maintain their viability. In this research an experimental design was conducted to optimize the parameters for high pressure processing (HPP) of apple juice (pH 3.76).Design/methodology/approachJuice was inoculated with cocktails of Escherichia coli O157:H7, Salmonella enterica and Listeria monocytogenes. Pressures ranging from 139 to 561 MPa and dwell times between 39 and 181 s were challenged.FindingsPressures above 400 MPa achieved a greater than 5-log reduction in all pathogen cocktails regardless of the dwell time. L. monocytogenes was more sensitive to HPP at a pressure of 350 MPa and dwell times equal to or beyond 110 s. E. coli O157:H7 and S. enterica exhibited similar resistance; the number of log reductions in the central point (350 MPa/110 s) ranged from 2.2 to 3.7. The first-order mathematical model better fitted experimental data for E. coli O157:H7 and S. enterica. In regard to L. monocytogenes, the second-order model better fitted this pathogen's reduction.Practical implicationsFruit juices are usually high pressure processed at approximately 600 MPa. For pathogenic reduction, the use of milder parameters may save energy and maintenance costs. The results herein exhibited could assist the apple juice industry with more effective applications of HPP.Originality/valueThe findings of this study demonstrate that relatively moderate pressures can be successfully used to assure the safety of apple juice.

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.

Inactivation of Escherichia coli Inoculated onto Fresh-Cut Chopped Cabbage Using Electron-Beam Processing

2011 ◽  
Vol 74 (1) ◽  
pp. 115-118 ◽  
Author(s):  
ELIZABETH M. GRASSO ◽  
ROBERTO M. URIBE-RENDON ◽  
KEN LEE
Keyword(s):  
Escherichia Coli ◽  
Electron Beam ◽  
Foodborne Pathogens ◽  
Optimal Dosage ◽  
Beam Irradiation ◽  
E Coli ◽  
Log Reduction ◽  
Fresh Cut ◽  
K 12 ◽  
Indigenous Microflora

During the past decade there were more than 50 reported outbreaks involving leafy green vegetables contaminated with foodborne pathogens. Leafy greens, including cabbage, are fresh foods rarely heated before consumption, which enables foodborne illness. The need for improved safety of fresh food drives the demand for nonthermal food processes to decrease the risk of pathogens while maintaining fresh quality. This study examines the efficacy of electron-beam (e-beam) irradiation in decreasing indigenous microflora on fresh-cut cabbage and determines the optimal dosage to pasteurize fresh-cut cabbage inoculated with Escherichia coli K-12. Fresh-cut cabbage (100 g) was inoculated with ~8 log E. coli K-12 and e-beam irradiated at doses of 0, 1.0, 2.3, or 4.0 kGy. At 2.3 kGy there was <1.0 log indigenous microflora remaining, indicating greater than a 4.0-log reduction by e-beam. At a 4.0-kGy dose there was >7-log reduction of E. coli K-12 in the fresh-cut cabbage. The D10-value for E. coli K-12 in fresh-cut cabbage was 0.564 kGy. E-beam irradiation is thus a viable nonthermal treatment that extends the shelf life and increases the safety of fresh cabbage by reducing or eliminating indigenous microflora and unwanted pathogens.

Efficacy of Chlorine Dioxide Gas as a Sanitizer of Lettuce Leaves

2004 ◽  
Vol 67 (7) ◽  
pp. 1371-1376 ◽  
Author(s):  
SUN-YOUNG LEE ◽  
MICHAEL COSTELLO ◽  
DONG-HYUN KANG
Keyword(s):  
Salmonella Typhimurium ◽  
Chlorine Dioxide ◽  
Foodborne Pathogens ◽  
Fruits And Vegetables ◽  
Hypochlorous Acid ◽  
Disease Outbreaks ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Log Reduction ◽  
Chlorine Dioxide Gas

Aqueous solutions of sodium hypochlorite or hypochlorous acid are typically used to sanitize fresh fruits and vegetables. However, pathogenic organisms occasionally survive aqueous sanitization in sufficient numbers to cause disease outbreaks. Chlorine dioxide (ClO2) gas generated by a dry chemical sachet was tested against foodborne pathogens on lettuce leaves. Lettuce leaves were inoculated with cocktail of three strains each of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium and treated with ClO2 gas for 30 min, 1 h, and 3 h in a model gas cabinet at room temperature (22 ± 2°C). After treatment, surviving cells, including injured cells, were enumerated on appropriate selective agar or using the overlay agar method, respectively. Total ClO2 generated by the gas packs was 4.3, 6.7, and 8.7 mg after 30 min, 1 h, and 3 h of treatment, respectively. Inoculated lettuce leaves exposed to ClO2 gas for 30 min experienced a 3.4-log reduction in E. coli, a 4.3-log reduction in Salmonella Typhimurium, and a 5.0-log reduction in L. monocytogenes when compared with the control. After 1 h, the three pathogens were reduced in number of CFU by 4.4, 5.3, and 5.2 log, respectively. After 3 h, the reductions were 6.9, 5.4, and 5.4 log, respectively. A similar pattern emerged when injured cells were enumerated. The ClO2 gas sachet was effective at killing pathogens on lettuce without deteriorating visual quality. Therefore, this product can be used during storage and transport of lettuce to improve its microbial safety.

Determination of 5-Log Reduction Times for Food Pathogens in Acidified Cucumbers during Storage at 10 and 25°C†‡

2007 ◽  
Vol 70 (11) ◽  
pp. 2638-2641 ◽  
Author(s):  
FRED BREIDT ◽  
JANET HAYES ◽  
ROGER F. MCFEETERS
Keyword(s):  
Foodborne Pathogens ◽  
Heat Processing ◽  
Thermal Treatments ◽  
Apple Cider ◽  
E Coli ◽  
Log Reduction ◽  
Ph Values ◽  
Vegetable Products ◽  
Resistant Microorganism

Outbreaks of acid-resistant foodborne pathogens in acid foods with pH values below 4.0, including apple cider and orange juice, have raised concerns about the safety of acidified vegetable products. For acidified vegetable products with pH values between 3.3 and 4.6, previous research has demonstrated that thermal treatments are needed to achieve a 5-log reduction in the numbers of Escherichia coli O157:H7, Listeria monocytogenes, or Salmonella enterica. For some acidified vegetable products with a pH of 3.3 or below, heat processing can result in unacceptable product quality. The purpose of this study was to determine the holding times needed to achieve a 5-log reduction in E. coli O157:H7, L. monocytogenes, and S. enterica strains in acidified vegetable products with acetic acid as the primary acidulant, a pH of 3.3 or below, and a minimum equilibrated temperature of 10°C. We found E. coli O157:H7 to be the most acid-resistant microorganism for the conditions tested, with a predicted time to achieve a 5-log reduction in cell numbers at 10°C of 5.7 days, compared with 2.1 days (51 h) for Salmonella or 0.5 days (11.2 h) for Listeria. At 25°C, the E. coli O157:H7 population achieved a 5-log reduction in 1.4 days (34.3 h).

Study of Atmospheric Microplasma for Plasma-Life Science

2012 ◽  
Vol 1469 ◽  
Author(s):  
Kazuo Shimizu ◽  
Shigeki Tatematsu ◽  
Hodaka Fukunaga ◽  
Marius Blajan
Keyword(s):  
Contact Angle ◽  
Surface Treatment ◽  
Life Science ◽  
Treatment Time ◽  
Polymer Surface ◽  
Active Species ◽  
Atmospheric Plasma ◽  
Emission Spectrometry ◽  
Science Field ◽  
E Coli

ABSTRACTAtmospheric microplasma has been intensively studied for various application fields, since this technology has features shown here: generated around only 1 kV under atmospheric pressure,discharge gap of only 10 to 100mm,dielectric barrier discharge. Low discharge voltage atmospheric plasma processis an economical and effective solution forvarious applications such as indoor air control including sterilization, odor removal, surface treatment, and would be suitable for plasma-life science field such as medical application.In thispaper, the basic study for plasma-life science will be presented. One life science application of microplasma is “sterilization”. The sterilization process was carried out with active species generated between themicroplasmaelectrodes.The active species were observed by emission spectrometry. The spectra showed the existence of active species, and the microplasma had typical characteristics of non-thermal plasma. Sterilization of E. coli was confirmed after microplasma treatment with Ar gas. The bacteria shape was changed after the microplasma process. The other application is “Surface treatment” by long life active species of materials which used for the medical field. The targets are glass, polymer film and others could be also possible.The process is known as remote microplasma sterilization method. Microplasma generated by both air and Ar are effective for sterilization. Observation by the SEM images shows the E. coli had a shrunked shape after the microplasma treatment.The contact angle of a water droplet on the polymer surface was measured to estimate its hydrophilicity. The relation between the contact angle and treatment time was investigated. Contact angle decreased from 75.6° to 45.6° after 10 s of treatment.

Reduction of Escherichia coli O157:H7 and Salmonella in Ground Beef Using Lactic Acid Bacteria and the Impact on Sensory Properties

2005 ◽  
Vol 68 (8) ◽  
pp. 1587-1592 ◽  
Author(s):  
L. SMITH ◽  
J. E. MANN ◽  
K. HARRIS ◽  
M. F. MILLER ◽  
M. M. BRASHEARS
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Foodborne Pathogens ◽  
Ground Beef ◽  
Sensory Properties ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Log Reduction ◽  
The Impact

Studies were conducted to determine whether four strains of lactic acid bacteria (LAB) inhibited Escherichia coli O157: H7 and Salmonella in ground beef at 5°C and whether these bacteria had an impact on the sensory properties of the beef. The LAB consisted of frozen concentrated cultures of four Lactobacillus strains, and a cocktail mixture of streptomycin-resistant E. coli O157:H7 and Salmonella were used as pathogens. Individual LAB isolates at 107 CFU/ml were added to tryptic soy broth containing a pathogen concentration of 105 CFU/ml. Samples were stored at 5°C, and pathogen populations were determined on days 0, 4, 8, and 12. After 4 days of storage, there were significant differences in numbers of both pathogens exposed to LAB isolates NP 35 and NP 3. After 8 and 12 days of storage, all LAB reduced populations of both pathogens by an average of 3 to 5 log cycles. A second study was conducted in vacuum-packaged fresh ground beef. The individual LAB isolates resulted in an average difference of 1.5 log cycles of E. coli O157:H7 after 12 days of storage, and Salmonella populations were reduced by an average of 3 log cycles. Following this study, a mixed concentrated culture was prepared from all four LAB and added to ground beef inoculated with pathogen at 108 CFU/g. After 3 days of storage, the mixed culture resulted in a 2.0-log reduction in E. coli O157:H7 compared with the control, whereas after 5 days of storage, a 3-log reduction was noted. Salmonella was reduced to nondetectable levels after day 5. Sensory studies on noninoculated samples that contained LAB indicated that there were no adverse effects of LAB on the sensory properties of the ground beef. This study indicates that adding LAB to raw ground beef stored at refrigeration temperatures may be an important intervention for controlling foodborne pathogens.

Location of Escherichia coli O157:H7 on and in Apples as Affected by Bruising, Washing, and Rubbing

2001 ◽  
Vol 64 (9) ◽  
pp. 1328-1333 ◽  
Author(s):  
STEPHEN J. KENNEY ◽  
SCOTT L. BURNETT ◽  
LARRY R. BEUCHAT
Keyword(s):  
Escherichia Coli ◽  
Fluorescent Protein ◽  
Skin Surface ◽  
Confocal Scanning Laser Microscopy ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Log Reduction ◽  
Peptone Water ◽  
Confocal Scanning Laser ◽  
Green Fluorescent

Confocal scanning laser microscopy (CSLM) was used to determine the location of Escherichia coli O157:H7 cells on the surface and in tissue of bruised Red Delicious cv. apples. Undamaged and bruised apples were inoculated by immersing in a suspension of E. coli O157:H7 cells transformed with a plasmid that encodes for the production of a green fluorescent protein. Apples were then washed in 0.1% (wt/vol) peptone water and/or rubbed with a polyester cloth and examined to determine if these treatments removed or introduced cells into lenticels, cutin, and cracks on the skin surface. Optical slices of the apples obtained using CSLM were examined to determine the depth at which colonization or attachment of cells occurred. Populations of E. coli O157:H7 on the surface of apples were determined to assess the effectiveness of washing and rubbing in physically removing cells. The location of cells on or in undamaged and bruised areas of apples that were not washed or rubbed did not differ significantly. However, washing apples resulted in an approximate 2-log reduction in CFU of E. coli O157:H7 per cm2 of apple surface. On unwashed apples, cells were detected at depths up to 30 μm below the surface. No E. coli O157:H7 cells were detected at locations more than 6 m below the surface of washed apples. Cells that remained on the surface of rubbed apples appeared to be sealed within naturally occurring cracks and crevices in waxy cutin platelets. These cells may be protected from disinfection and subsequently released when apples are eaten or pressed for cider production.

scholarly journals Inactivation of Bacteria Using Bioactive Nanoparticles and Alternating Magnetic Fields

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 342
Author(s):  
Vitalij Novickij ◽  
Ramunė Stanevičienė ◽  
Rūta Gruškienė ◽  
Kazimieras Badokas ◽  
Juliana Lukša ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Foodborne Pathogens ◽  
Morphological Changes ◽  
Foodborne Pathogen ◽  
Cellular Damage ◽  
Suitable Model ◽  
Log Reduction ◽  
Invasive Infections ◽  
Alternating Magnetic Fields ◽  
Inactivation Of Bacteria

Foodborne pathogens are frequently associated with risks and outbreaks of many diseases; therefore, food safety and processing remain a priority to control and minimize these risks. In this work, nisin-loaded magnetic nanoparticles were used and activated by alternating 10 and 125 mT (peak to peak) magnetic fields (AMFs) for biocontrol of bacteria Listeria innocua, a suitable model to study the inactivation of common foodborne pathogen L. monocytogenes. It was shown that L. innocua features high resistance to nisin-based bioactive nanoparticles, however, application of AMFs (15 and 30 min exposure) significantly potentiates the treatment resulting in considerable log reduction of viable cells. The morphological changes and the resulting cellular damage, which was induced by the synergistic treatment, was confirmed using scanning electron microscopy. The thermal effects were also estimated in the study. The results are useful for the development of new methods for treatment of the drug-resistant foodborne pathogens to minimize the risks of invasive infections. The proposed methodology is a contactless alternative to the currently established pulsed-electric field-based treatment in food processing.

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