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.

scholarly journals Critical Concentration of Lecithin Enhances the Antimicrobial Activity of Eugenol against Escherichia coli

2017 ◽  
Vol 83 (8) ◽  
Author(s):  
Haoshu Zhang ◽  
Edward G. Dudley ◽  
P. Michael Davidson ◽  
Federico Harte
Keyword(s):  
Escherichia Coli ◽  
Essential Oils ◽  
Food Systems ◽  
Critical Concentration ◽  
Physical Stability ◽  
Antimicrobial Properties ◽  
Content Type ◽  
Antimicrobial Effects ◽  
Wide Range ◽  
The Stability

ABSTRACT Lecithin is a natural emulsifier used in a wide range of food and nonfood applications to improve physical stability, with no known bioactive effects. In this study, the effect of lecithin on the antimicrobial performance of a constant eugenol concentration was tested against three Escherichia coli strains (C600, 0.1229, and O157:H7 strain ATCC 700728). This is the first study, to our knowledge, focusing on lecithin at concentrations below those commonly used in foods to improve the stability of oil in water emulsions (≤10 mg/100 ml). For all three cultures, significant synergistic antimicrobial effects were observed when E. coli cultures were exposed to a constant eugenol concentration (ranging from 0.043 to 0.050% [wt/wt]) together with critical lecithin concentrations ranging from 0.5 to 1 mg/100 ml. Increasing the concentration of lecithin above 1 mg/100 ml (up to 10 mg/100 ml lecithin) diminished the antibacterial effect to values similar to those with eugenol-only treatments. The formation of aggregates (<100 nm) at the critical lecithin concentration was observed using cryo-transmission electron microscopy (cryo-TEM), together with a reduction in light absorbance at 284 nm. At critically low concentrations of lecithin, the formation of nanoscale aggregates is responsible for improving eugenol antimicrobial effects. IMPORTANCE Essential oils (EOs) are effective natural antimicrobials. However, their hydrophobicity and strong aromatic character limit the use of essential oils in food systems. Emulsifiers (e.g., lecithin) increase the stability of EOs in water-based systems but fail to consistently improve antimicrobial effects. We demonstrate that lecithin, within a narrow critical concentration window, can enhance the antimicrobial properties of eugenol. This study highlights the potential bioactivity of lecithin when utilized to effectively control foodborne pathogens.

scholarly journals Fitness of Enterohemorrhagic Escherichia coli (EHEC)/Enteroaggregative E. coli O104:H4 in Comparison to That of EHEC O157: Survival Studies in Food andIn Vitro

2016 ◽  
Vol 82 (21) ◽  
pp. 6326-6334 ◽  
Author(s):  
Christina Böhnlein ◽  
Jan Kabisch ◽  
Diana Meske ◽  
Charles M. A. P. Franz ◽  
Rohtraud Pichner
Keyword(s):  
Escherichia Coli ◽  
Meat Product ◽  
Enterohemorrhagic Escherichia Coli ◽  
Content Type ◽  
E Coli ◽  
Adverse Conditions ◽  
Log Reduction ◽  
Fermented Sausages ◽  
Survival Studies

ABSTRACTIn 2011, one of the world's largest outbreaks of hemolytic-uremic syndrome (HUS) occurred, caused by a rareEscherichia coliserotype, O104:H4, that shared the virulence profiles of Shiga toxin-producingE. coli(STEC)/enterohemorrhagicE. coli(EHEC) and enteroaggregativeE. coli(EAEC). The persistence and fitness factors of the highly virulent EHEC/EAEC O104:H4 strain, grown either in food orin vitro, were compared with those ofE. coliO157 outbreak-associated strains. The log reduction rates of the different EHEC strains during the maturation of fermented sausages were not significantly different. Both the O157:NM and O104:H4 serotypes could be shown by qualitative enrichment to be present after 60 days of sausage storage. Moreover, the EHEC/EAEC O104:H4 strain appeared to be more viable thanE. coliO157:H7 under conditions of decreased pH and in the presence of sodium nitrite. Analysis of specific EHEC strains in experiments with an EHEC inoculation cocktail showed a dominance of EHEC/EAEC O104:H4, which could be isolated from fermented sausages for 60 days. Inhibitory activities of EHEC/EAEC O104:H4 toward severalE. colistrains, including serotype O157 strains, could be determined. Our study suggests that EHEC/EAEC O104:H4 is well adapted to the multiple adverse conditions occurring in fermented raw sausages. Therefore, it is strongly recommended that STEC strain cocktails composed of several serotypes, instead ofE. coliO157:H7 alone, be used in food risk assessments. The enhanced persistence of EHEC/EAEC O104:H4 as a result of its robustness, as well as the production of bacteriocins, may account for its extraordinary virulence potential.IMPORTANCEIn 2011, a severe outbreak caused by an EHEC/EAEC serovar O104:H4 strain led to many HUS sequelae. In this study, the persistence of the O104:H4 strain was compared with those of other outbreak-relevant STEC strains under conditions of fermented raw sausage production. Both O157:NM and O104:H4 strains could survive longer during the production of fermented sausages thanE. coliO157:H7 strains.E. coliO104:H4 was also shown to be well adapted to the multiple adverse conditions encountered in fermented sausages, and the secretion of a bacteriocin may explain the competitive advantage of this strain in an EHEC strain cocktail. Consequently, this study strongly suggests that enhanced survival and persistence, and the presumptive production of a bacteriocin, may explain the increased virulence of the O104:H4 outbreak strain. Furthermore, this strain appears to be capable of surviving in a meat product, suggesting that meat should not be excluded as a source of potentialE. coliO104:H4 infection.

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).

scholarly journals Genome Sequence of a Podovirus (AAPEc6) Isolated from Wastewater in New Zealand That Infects Escherichia coli O45:H10

2017 ◽  
Vol 5 (31) ◽  
Author(s):  
Judith Nonis ◽  
Aruni Premaratne ◽  
Craig Billington ◽  
Arvind Varsani
Keyword(s):  
Escherichia Coli ◽  
New Zealand ◽  
Genome Sequence ◽  
Foodborne Pathogens ◽  
Content Type ◽  
E Coli

ABSTRACT Bacteriophages are ideal candidates for pathogen biocontrol to mitigate outbreaks of prevalent foodborne pathogens, such as Escherichia coli. We identified a bacteriophage (AAPEc6) from wastewater that infects E. coli O45:H10. The AAPEc6 genome sequence shares 93% identity (with 92% coverage) to enterobacterial phage K1E (Sp6likevirus) in the Autographivirinae subfamily (Podoviridae).

scholarly journals Escherichia coli Survival in, and Release from, White-Tailed Deer Feces

2014 ◽  
Vol 81 (3) ◽  
pp. 1168-1176 ◽  
Author(s):  
Andrey K. Guber ◽  
Jessica Fry ◽  
Rebecca L. Ives ◽  
Joan B. Rose
Keyword(s):  
Escherichia Coli ◽  
Fate And Transport ◽  
Exponential Model ◽  
Temperature Correction ◽  
Content Type ◽  
E Coli ◽  
Naturally Occurring ◽  
Different Temperatures ◽  
Kinetics Of ◽  
Source Materials

ABSTRACTWhite-tailed deer are an important reservoir for pathogens that can contribute a large portion of microbial pollution in fragmented agricultural and forest landscapes. The scarcity of experimental data on survival of microorganisms in and release from deer feces makes prediction of their fate and transport less reliable and development of efficient strategies for environment protection more difficult. The goal of this study was to estimate parameters for modelingEscherichia colisurvival in and release from deer (Odocoileus virginianus) feces. Our objectives were as follows: (i) to measure survival ofE. coliin deer pellets at different temperatures, (ii) to measure kinetics ofE. colirelease from deer pellets at different rainfall intensities, and (iii) to estimate parameters of models describing survival and release of microorganisms from deer feces. Laboratory experiments were conducted to studyE. colisurvival in deer pellets at three temperatures and to estimate parameters of Chick's exponential model with temperature correction based on the Arrhenius equation. Kinetics ofE. colirelease from deer pellets were measured at two rainfall intensities and used to derive the parameters of Bradford-Schijven model of bacterial release. The results showed that parameters of the survival and release models obtained forE. coliin this study substantially differed from those obtained by using other source materials, e.g., feces of domestic animals and manures. This emphasizes the necessity of comprehensive studies of survival of naturally occurring populations of microorganisms in and release from wildlife animal feces in order to achieve better predictions of microbial fate and transport in fragmented agricultural and forest landscapes.

scholarly journals Acute Limonene Toxicity in Escherichia coli Is Caused by Limonene Hydroperoxide and Alleviated by a Point Mutation in Alkyl Hydroperoxidase AhpC

2015 ◽  
Vol 81 (14) ◽  
pp. 4690-4696 ◽  
Author(s):  
Victor Chubukov ◽  
Florence Mingardon ◽  
Wendy Schackwitz ◽  
Edward E. K. Baidoo ◽  
Jorge Alonso-Gutierrez ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Properties ◽  
Wild Type ◽  
Food Preservative ◽  
Citrus Peel ◽  
Content Type ◽  
E Coli ◽  
The Common ◽  
Alkyl Hydroperoxidase ◽  
Peel Oil

ABSTRACTLimonene, a major component of citrus peel oil, has a number of applications related to microbiology. The antimicrobial properties of limonene make it a popular disinfectant and food preservative, while its potential as a biofuel component has made it the target of renewable production efforts through microbial metabolic engineering. For both applications, an understanding of microbial sensitivity or tolerance to limonene is crucial, but the mechanism of limonene toxicity remains enigmatic. In this study, we characterized a limonene-tolerant strain ofEscherichia coliand found a mutation inahpC, encoding alkyl hydroperoxidase, which alleviated limonene toxicity. We show that the acute toxicity previously attributed to limonene is largely due to the common oxidation product limonene hydroperoxide, which forms spontaneously in aerobic environments. The mutant AhpC protein with an L-to-Q change at position 177 (AhpCL177Q) was able to alleviate this toxicity by reducing the hydroperoxide to a more benign compound. We show that the degree of limonene toxicity is a function of its oxidation level and that nonoxidized limonene has relatively little toxicity to wild-typeE. colicells. Our results have implications for both the renewable production of limonene and the applications of limonene as an antimicrobial.

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.

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 &lt;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 &gt;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.

Soil Solarization Reduces Escherichia coli O157:H7 and Total Escherichia coli on Cattle Feedlot Pen Surfaces†

2012 ◽  
Vol 75 (1) ◽  
pp. 7-13 ◽  
Author(s):  
ELAINE D. BERRY ◽  
JAMES E. WELLS
Keyword(s):  
Escherichia Coli ◽  
Immunomagnetic Separation ◽  
Sampling Time ◽  
Soil Solarization ◽  
Food Crops ◽  
Escherichia Coli O157 ◽  
Cattle Production ◽  
E Coli ◽  
Log Reduction ◽  
Naturally Occurring

Feedlot pen soil is a source for transmission of Escherichia coli O157:H7, and therefore a target for preharvest strategies to reduce this pathogen in cattle. The objective of this study was to determine the ability of soil solarization to reduce E. coli O157:H7 in feedlot surface material (FSM). A feedlot pen was identified in which naturally occurring E. coli O157:H7 was prevalent and evenly distributed in the FSM. Forty plots 3 by 3 m were randomly assigned such that five plots of each of the solarization times of 0, 1, 2, 3, 4, 6, 8, and 10 weeks were examined. Temperature loggers were placed 7.5 cm below the surface of each plot, and plots to be solarized were covered with clear 6-mil polyethylene. At each sampling time, five FSM samples were collected from each of five solarized and five unsolarized plots. E. coli concentrations and E. coli O157:H7 presence by immunomagnetic separation and plating were determined for each FSM sample. Initial percentages of E. coli O157:H7–positive samples in control and solarized FSM were 84 and 80%, respectively, and did not differ (P &gt; 0.05). E. coli O157:H7 was no longer detectable by 8 weeks of solarization, but was still detected in unsolarized FSM at 10 weeks. The average initial concentration of E. coli in FSM was 5.56 log CFU/g and did not differ between treatments (P &gt; 0.05). There was a 2.0-log decrease of E. coli after 1 week of solarization, and a &gt;3.0-log reduction of E. coli by week 6 of solarization (P &lt; 0.05). E. coli levels remained unchanged in unsolarized FSM (P &gt; 0.05). Daily peak FSM temperatures were on average 8.7°C higher for solarized FSM compared with unsolarized FSM, and reached temperatures as high as 57°C. Because soil solarization reduces E. coli O157:H7, this technique may be useful for reduction of persistence and transmission of this pathogen in cattle production, in addition to remediation of E. coli O157:H7–contaminated soil used to grow food crops.

scholarly journals Soil Conditions That Can Alter Natural Suppression of Escherichia coli O157:H7 in Ohio Specialty Crop Soils

2015 ◽  
Vol 81 (14) ◽  
pp. 4634-4641 ◽  
Author(s):  
Michele L. Williams ◽  
Jeffrey T. LeJeune ◽  
Brian McSpadden Gardener
Keyword(s):  
Escherichia Coli ◽  
Moisture Content ◽  
Soil Ph ◽  
Soil Conditions ◽  
Longitudinal Field ◽  
Content Type ◽  
E Coli ◽  
Log Reduction ◽  
Specialty Crop ◽  
Complex Relationships

ABSTRACTFood-borne pathogen persistence in soil fundamentally affects the production of safe vegetables and small fruits. Interventions that reduce pathogen survival in soil would have positive impacts on food safety by minimizing preharvest contamination entering the food chain. Laboratory-controlled studies determined the effects of soil pH, moisture content, and soil organic matter (SOM) on the survivability of this pathogen through the creation of single-parameter gradients. Longitudinal field-based studies were conducted in Ohio to quantify the extent to which field soils suppressedEscherichia coliO157:H7 survival. In all experiments, heat-sensitive microorganisms were responsible for the suppression ofE. coliO157 in soil regardless of the chemical composition of the soil. In laboratory-based studies, soil pH and moisture content were primary drivers ofE. coliO157 survival, with increases in pH after 48 h (P= 0.02) and decreases in moisture content after 48 h (P= 0.007) significantly increasing the log reduction ofE. coliO157 numbers. In field-based experiments,E. coliO157 counts from both heated and unheated samples were sensitive to both season (P= 0.004 for heated samples andP= 0.001 for unheated samples) and region (P= 0.002 for heated samples andP= 0.001 for unheated samples). SOM was observed to be a more significant driver of pathogen suppression than the other two factors after 48 h at both planting and harvest (P= 0.002 at planting andP= 0.058 at harvest). This research reinforces the need for both laboratory-controlled experiments and longitudinal field-based experiments to unravel the complex relationships controlling the survival of introduced organisms in soil.

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