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.

scholarly journals Effect of Electron Beam Irradiation on Survival of Escherichia coli O157:H7 and Salmonella enterica serovar Thyphimurium in Minced Camel Meat during Refrigerated Storage

2019 ◽  
Author(s):  
A. Amiri ◽  
H. Zandi ◽  
H. Mozaffari Khosravi
Keyword(s):  
Escherichia Coli ◽  
Electron Beam ◽  
Electron Beam Irradiation ◽  
Escherichia Coli O157 ◽  
Refrigerated Storage ◽  
Beam Irradiation ◽  
E Coli ◽  
Serovar Typhimurium ◽  
Camel Meat ◽  
Meat Samples

Background: Electron beam irradiation is one of the effective ways to control foodborne pathogens. We evaluated the effect of electron beam irradiation on survival of Escherichia coli O157:H7 and Salmonella enterica serovar Thyphimurium in minced camel meat during refrigerated storage. Methods: The meat samples were inoculated with E. coli O157:H7 and S. enterica serovar Thyphimurium and then irradiated with doses of 0, 1, 2, 3, and 5 kGy. The samples were stored at 4±1 °C and evaluated microbiologically up to 10 days. Data were analyzed using SPSS software version 18. Results: The microbial loads of minced camel meat samples were significantly reduced (p<0.0001) with increasing the dose of irradiation. The most effective dose was 5 kGy that highly reduced S. enterica serovar Typhimurium, and completely destroyed E. coli O157:H7. However, E. coli O157:H7 was more sensitive to electron beam irradiation than S. enterica serovar Typhimurium. Conclusion: Electron beam irradiation effectively reduced the population of both E. coli O157:H7 and S. enterica serovar Typhimurium in minced camel meat in a dose dependent manner.

Quantitative Microbial Risk Assessment for Escherichia coli O157:H7 in Fresh-Cut Lettuce

2017 ◽  
Vol 80 (2) ◽  
pp. 302-311 ◽  
Author(s):  
Hao Pang ◽  
Elisabetta Lambertini ◽  
Robert L. Buchanan ◽  
Donald W. Schaffner ◽  
Abani K. Pradhan
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
The United States ◽  
Intervention Strategies ◽  
Sensitivity Analyses ◽  
Escherichia Coli O157 ◽  
Baseline Model ◽  
Microbial Risk ◽  
E Coli ◽  
Fresh Cut

ABSTRACT Leafy green vegetables, including lettuce, are recognized as potential vehicles for foodborne pathogens such as Escherichia coli O157:H7. Fresh-cut lettuce is potentially at high risk of causing foodborne illnesses, as it is generally consumed without cooking. Quantitative microbial risk assessments (QMRAs) are gaining more attention as an effective tool to assess and control potential risks associated with foodborne pathogens. This study developed a QMRA model for E. coli O157:H7 in fresh-cut lettuce and evaluated the effects of different potential intervention strategies on the reduction of public health risks. The fresh-cut lettuce production and supply chain was modeled from field production, with both irrigation water and soil as initial contamination sources, to consumption at home. The baseline model (with no interventions) predicted a mean probability of 1 illness per 10 million servings and a mean of 2,160 illness cases per year in the United States. All intervention strategies evaluated (chlorine, ultrasound and organic acid, irradiation, bacteriophage, and consumer washing) significantly reduced the estimated mean number of illness cases when compared with the baseline model prediction (from 11.4- to 17.9-fold reduction). Sensitivity analyses indicated that retail and home storage temperature were the most important factors affecting the predicted number of illness cases. The developed QMRA model provided a framework for estimating risk associated with consumption of E. coli O157:H7–contaminated fresh-cut lettuce and can guide the evaluation and development of intervention strategies aimed at reducing such risk.

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.

Nonthermal Inactivation of Escherichia coli K-12 on Spinach Leaves, Using Dense Phase Carbon Dioxide

2008 ◽  
Vol 71 (5) ◽  
pp. 1015-1017 ◽  
Author(s):  
QIXIN ZHONG ◽  
D. GLENN BLACK ◽  
P. MICHAEL DAVIDSON ◽  
DAVID A. GOLDEN
Keyword(s):  
Escherichia Coli ◽  
Carbon Dioxide ◽  
Foodborne Pathogens ◽  
Fruits And Vegetables ◽  
Subcritical State ◽  
Dense Phase ◽  
Log Reduction ◽  
Treatment Conditions ◽  
K 12 ◽  
Spinach Leaves

While the use of some chemical sanitizers is approved for inactivation of microbes on the surfaces of fruits and vegetables, these compounds often degrade product quality with limited improvement in product safety. The application of dense phase carbon dioxide (DPCD, or high-pressure CO2) is a nonthermal process for inactivation of foodborne pathogens inoculated into various juices and model solutions. In this work, DPCD was evaluated for its potential to inactivate Escherichia coli K-12 inoculated on fresh spinach leaves. Inoculated leaves were exposed for up to 40 min to DPCD at a subcritical condition (5 MPa, 40°C) and two supercritical conditions (7.5 and 10 MPa, 40°C) at a flow rate of 50 g of CO2/min. E. coli K-12 populations were reduced to nondetectable levels (~5-log reduction) using supercritical treatment conditions at exposure times as short as 10 min; efficacy of DPCD at the subcritical state was limited. This research demonstrates that DPCD has potential as a pasteurization technology for application to leafy green vegetables, although issues with discoloration and other quality measures will need more extensive evaluations.

Inactivation of Escherichia coli O157:H7 and Other Naturally Occurring Microorganisms in Apple Cider by Electron Beam Irradiation

2004 ◽  
Vol 67 (8) ◽  
pp. 1574-1577 ◽  
Author(s):  
HUI WANG ◽  
CHERYLL A. REITMEIER ◽  
BONITA A. GLATZ
Keyword(s):  
Escherichia Coli ◽  
Electron Beam ◽  
Electron Beam Irradiation ◽  
Escherichia Coli O157 ◽  
Beam Irradiation ◽  
Accelerator Facility ◽  
Apple Cider ◽  
E Coli ◽  
Naturally Occurring ◽  
D Values

Two Escherichia coli O157:H7 strains, SEA 13 B88 gfp 73ec and B6-914 gfp 90ec, together with two bacteria, three yeasts, and two molds that were randomly selected from a collection of microorganisms found on apples or in apple cider, were inoculated into apple cider and subjected to electron beam irradiation at several doses between 0.0 and 2.3 kGy at the Iowa State University Linear Accelerator Facility. The D-values for the E. coli O157:H7 strains ranged between 0.25 and 0.34 kGy; the D-values for most of the normal flora from apples ranged between 0.24 and 0.59 kGy. By taking into account possible variations in treatment conditions, it was calculated that irradiation at 2.47 kGy should achieve a 5-log reduction of E. coli O157:H7 in apple cider at the 95% confidence level. Naturally occurring yeasts might survive such irradiation treatment.

Biological Control of Postharvest Decays of Apple Can Prevent Growth of Escherichia coli O157:H7 in Apple Wounds

1999 ◽  
Vol 62 (12) ◽  
pp. 1372-1375 ◽  
Author(s):  
W. J. JANISIEWICZ ◽  
W. S. CONWAY ◽  
B. LEVERENTZ
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Syringae ◽  
Foodborne Pathogens ◽  
Additional Benefit ◽  
Escherichia Coli O157 ◽  
Water Control ◽  
Commercial Formulation ◽  
E Coli ◽  
Golden Delicious ◽  
Fresh Cut

Fresh cells of the antagonist Pseudomonas syringae at 2.4 × 108 CFU/ml inoculated into wounds of ‘Golden Delicious’ apple prevented Escherichia coli O157:H7 (concentrations ranging from 2.4 × 105 to 2.4 × 107 CFU/ml) from growing in the wounds. This occurred when the two microorganisms were co-inoculated or inoculation with E. coli O157:H7 was conducted 1 or 2 days after inoculation with the antagonist. In similar tests, application of the commercial formulation of this antagonist prevented the growth of E. coli O157:H7 in wounds when inoculated 1 or 2 days after application of the antagonist. Populations of E. coli O157:H7 in wounds treated with water (control) before inoculation with this pathogen increased approximately 2 log units during the first 48 h after inoculation. These results indicate that biocontrol agents developed for controlling storage decays of fruits may have the additional benefit of preventing the growth of foodborne pathogens in freshly wounded tissue of intact and fresh-cut fruits.

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.

Survival of Salmonella and Escherichia coli O157:H7 on Strawberries, Basil, and Other Leafy Greens during Storage

2015 ◽  
Vol 78 (4) ◽  
pp. 652-660 ◽  
Author(s):  
STEFANIE DELBEKE ◽  
SIELE CEUPPENS ◽  
LIESBETH JACXSENS ◽  
MIEKE UYTTENDAELE
Keyword(s):  
Escherichia Coli ◽  
Limit Of Detection ◽  
Escherichia Coli O157 ◽  
Similar Reduction ◽  
Initial Inoculum ◽  
E Coli ◽  
Log Reduction ◽  
Leafy Greens ◽  
Fresh Cut ◽  
Butterhead Lettuce

The survival of Salmonella and Escherichia coli O157:H7 on strawberries, basil leaves, and other leafy greens (spinach leaves, lamb and butterhead lettuce leaves, baby leaves, and fresh-cut iceberg lettuce) was assessed at cold (&lt;7°C) and ambient temperatures. All commodities were spot inoculated with E. coli O157:H7 or Salmonella to obtain an initial inoculum of 5 to 6 log and 4 to 5 log CFU/g for strawberries and leafy greens, respectively. Samples were air packed. Strawberries were stored at 4, 10, 15, and 22°C and basil leaves and other leafy greens at 7, 15, and 22°C for up to 7 days (or less if spoiled before). Both Salmonella and E. coli O157:H7 showed a gradual decrease in numbers if inoculated on strawberries, with a similar reduction observed at 4, 10, and 15°C (2 to 3 log after 5 days). However, at 15°C (and 10°C for E. coli O157:H7), the survival experiment stopped before day 7, as die-off of both pathogens below the lower limit of detection was achieved or spoilage occurred. At 22°C, strawberries were moldy after 2 or 4 days. At that time, a 1- to 2-log reduction of both pathogens had occurred. A restricted die-off (on average 1.0 log) and increase (on average &lt;0.5 log) of both pathogens on basil leaves occurred after 7 days of storage at 7 and 22°C, respectively. On leafy greens, a comparable decrease as on basil was observed after 3 days at 7°C. At 22°C, both pathogens increased to higher numbers on fresh-cut iceberg and butterhead lettuce leaves (on average 1.0 log), probably due to the presence of exudates. However, by using spot inoculation, the increase was rather limited, probably due to minimized contact between the inoculum and cell exudates. Avoiding contamination, in particular, at cultivation (and harvest or postharvest) is important, as both pathogens survive during storage, and strawberries, basil, and other leafy green leaves are consumed without inactivation treatment.

Effect of Hydrogen Peroxide in Combination with Minimal Thermal Treatment for Reducing Bacterial Populations on Cantaloupe Rind Surfaces and Transfer to Fresh-Cut Pieces

2016 ◽  
Vol 79 (8) ◽  
pp. 1316-1324 ◽  
Author(s):  
DIKE O. UKUKU ◽  
SUDARSAN MUKHOPADHYAY ◽  
DAVID GEVEKE ◽  
MODESTO OLANYA ◽  
BRENDAN NIEMIRA
Keyword(s):  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Combination Treatment ◽  
Bacterial Pathogens ◽  
Escherichia Coli O157 ◽  
Bacterial Populations ◽  
E Coli ◽  
Log Reduction ◽  
Fresh Cut ◽  
Bacterial Cell Morphology

ABSTRACT Surface structure and biochemical characteristics of bacteria and produce play a major role in how and where bacteria attach, complicating decontamination treatments. Whole cantaloupe rind surfaces were inoculated with Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes at 107 CFU/ml. Average population size of Salmonella, Escherichia coli O157:H7, and L. monocytogenes recovered after surface inoculation was 4.8 ± 0.12, 5.1 ± 0.14, and 3.6 ± 0.13 log CFU/cm2, respectively. Inoculated melons were stored at 5 and 22°C for 7 days before washing treatment interventions. Intervention treatments used were (i) water (H2O) at 22°C, (ii) H2O at 80°C, (iii) 3% hydrogen peroxide (H2O2) at 22°C, and (iv) a combination of 3% H2O2 and H2O at 80°C for 300 s. The strength of pathogen attachment (SR value) at days 0, 3, and 7 of storage was determined, and then the efficacy of the intervention treatments to detach, kill, and reduce transfer of bacteria to fresh-cut pieces during fresh-cut preparation was investigated. Populations of E. coli O157:H7 attached to the rind surface at significantly higher levels (P &lt; 0.05) than Salmonella and L. monocytogenes, but Salmonella exhibited the strongest attachment (SR value) at all days tested. Washing with 3% H2O2 alone led to significant reduction (P &lt; 0.05) of bacteria and caused some changes in bacterial cell morphology. A combination treatment with H2O and 3% H2O2 at 80°C led to an average 4-log reduction of bacterial pathogens, and no bacterial pathogens were detected in fresh-cut pieces prepared from this combination treatment, including enriched fresh-cut samples. The results of this study indicate that the microbial safety of fresh-cut pieces from treated cantaloupes was improved at day 6 of storage at 5°C and day 3 of storage at 10°C.

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