Electrostatic Spray of Food-Grade Organic Acids and Plant Extract to Reduce Escherichia coli O157:H7 on Fresh-Cut Cantaloupe Cubes

2013 ◽  
Vol 33 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Leighanna M. Massey ◽  
Navam S. Hettiarachchy ◽  
Elizabeth M. Martin ◽  
Steven C. Ricke
Keyword(s):  
Escherichia Coli ◽  
Organic Acids ◽  
Plant Extract ◽  
Escherichia Coli O157 ◽  
Food Grade ◽  
Fresh Cut ◽  
Electrostatic Spray

Tracking an Escherichia coli O157:H7–Contaminated Batch of Leafy Greens through a Pilot-Scale Fresh-Cut Processing Line

2014 ◽  
Vol 77 (9) ◽  
pp. 1487-1494 ◽  
Author(s):  
ANNEMARIE L. BUCHHOLZ ◽  
GORDON R. DAVIDSON ◽  
BRADLEY P. MARKS ◽  
EWEN C. D. TODD ◽  
ELLIOT T. RYSER
Keyword(s):  
Escherichia Coli ◽  
Membrane Filtration ◽  
Fluorescent Protein ◽  
Pilot Scale ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Leafy Greens ◽  
Iceberg Lettuce ◽  
Processing Line ◽  
Fresh Cut

Cross-contamination of fresh-cut leafy greens with residual Escherichia coli O157:H7–contaminated product during commercial processing was likely a contributing factor in several recent multistate outbreaks. Consequently, radicchio was used as a visual marker to track the spread of the contaminated product to iceberg lettuce in a pilot-scale processing line that included a commercial shredder, step conveyor, flume tank, shaker table, and centrifugal dryer. Uninoculated iceberg lettuce (45 kg) was processed, followed by 9.1 kg of radicchio (dip inoculated to contain a four-strain, green fluorescent protein–labeled nontoxigenic E. coli O157:H7 cocktail at 106 CFU/g) and 907 kg (2,000 lb) of uninoculated iceberg lettuce. After collecting the lettuce and radicchio in about 40 bags (~22.7 kg per bag) along with water and equipment surface samples, all visible shreds of radicchio were retrieved from the bags of shredded product, the equipment, and the floor. E. coli O157:H7 populations were quantified in the lettuce, water, and equipment samples by direct plating with or without prior membrane filtration on Trypticase soy agar containing 0.6% yeast extract and 100 ppm of ampicillin. Based on triplicate experiments, the weight of radicchio in the shredded lettuce averaged 614.9 g (93.6%), 6.9 g (1.3%), 5.0 g (0.8%), and 2.8 g (0.5%) for bags 1 to 10, 11 to 20, 21 to 30, and 31 to 40, respectively, with mean E. coli O157:H7 populations of 1.7, 1.2, 1.1, and 1.1 log CFU/g in radicchio-free lettuce. After processing, more radicchio remained on the conveyor (9.8 g; P < 0.05), compared with the shredder (8.3 g), flume tank (3.5 g), and shaker table (0.1 g), with similar E. coli O157:H7 populations (P > 0.05) recovered from all equipment surfaces after processing. These findings clearly demonstrate both the potential for the continuous spread of contaminated lettuce to multiple batches of product during processing and the need for improved equipment designs that minimize the buildup of residual product during processing.

Evaluation of Gaseous Chlorine Dioxide as a Sanitizer for Killing Salmonella, Escherichia coli O157:H7, Listeria monocytogenes, and Yeasts and Molds on Fresh and Fresh-Cut Produce

2005 ◽  
Vol 68 (6) ◽  
pp. 1176-1187 ◽  
Author(s):  
KAYE V. SY ◽  
MELINDA B. MURRAY ◽  
M. DAVID HARRISON ◽  
LARRY R. BEUCHAT
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Chlorine Dioxide ◽  
Foodborne Pathogens ◽  
Escherichia Coli O157 ◽  
Gaseous Chlorine Dioxide ◽  
Sensory Qualities ◽  
A Cell ◽  
Fresh Cut ◽  
Yeasts And Molds

Gaseous chlorine dioxide (ClO2) was evaluated for effectiveness in killing Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes on fresh-cut lettuce, cabbage, and carrot and Salmonella, yeasts, and molds on apples, peaches, tomatoes, and onions. Inoculum (100 μl, ca. 6.8 log CFU) containing five serotypes of Salmonella enterica, five strains of E. coli O157:H7, or five strains of L. monocytogenes was deposited on the skin and cut surfaces of fresh-cut vegetables, dried for 30 min at 22°C, held for 20 h at 4°C, and then incubated for 30 min at 22°C before treatment. The skin surfaces of apples, peaches, tomatoes, and onions were inoculated with 100 μl of a cell suspension (ca. 8.0 log CFU) containing five serotypes of Salmonella, and inoculated produce was allowed to dry for 20 to 22 h at 22°C before treatment. Treatment with ClO2 at 4.1 mg/liter significantly (α = 0.05) reduced the population of foodborne pathogens on all produce. Reductions resulting from this treatment were 3.13 to 4.42 log CFU/g for fresh-cut cabbage, 5.15 to 5.88 log CFU/g for fresh-cut carrots, 1.53 to 1.58 log CFU/g for fresh-cut lettuce, 4.21 log CFU per apple, 4.33 log CFU per tomato, 1.94 log CFU per onion, and 3.23 log CFU per peach. The highest reductions in yeast and mold populations resulting from the same treatment were 1.68 log CFU per apple and 2.65 log CFU per peach. Populations of yeasts and molds on tomatoes and onions were not significantly reduced by treatment with 4.1 mg/liter ClO2. Substantial reductions in populations of pathogens on apples, tomatoes, and onions but not peaches or fresh-cut cabbage, carrot, and lettuce were achieved by treatment with gaseous ClO2 without markedly adverse effects on sensory qualities.

scholarly journals Modeling of Free Chlorine Consumption and Escherichia coli O157:H7 Cross‐Contamination During Fresh‐Cut Produce Wash Cycles

2019 ◽  
Vol 84 (10) ◽  
pp. 2736-2744 ◽  
Author(s):  
Mohammadreza Dehghan Abnavi ◽  
Ali Alradaan ◽  
Daniel Munther ◽  
Chandrasekhar R. Kothapalli ◽  
Parthasarathy Srinivasan
Keyword(s):  
Escherichia Coli ◽  
Free Chlorine ◽  
Escherichia Coli O157 ◽  
Cross Contamination ◽  
Fresh Cut

Effect of Modified Atmosphere Packaging on the Persistence and Expression of Virulence Factors of Escherichia coli O157:H7 on Shredded Iceberg Lettuce†

2011 ◽  
Vol 74 (5) ◽  
pp. 718-726 ◽  
Author(s):  
MANAN SHARMA ◽  
SUDESNA LAKSHMAN ◽  
SEAN FERGUSON ◽  
DAVID T. INGRAM ◽  
YAGUANG LUO ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Modified Atmosphere Packaging ◽  
Ambient Air ◽  
Modified Atmosphere ◽  
Escherichia Coli O157 ◽  
Atmospheric Conditions ◽  
E Coli ◽  
Leafy Greens ◽  
Fresh Cut

Fresh-cut leafy greens contaminated with Escherichia coli O157:H7 have caused foodborne outbreaks. Packaging conditions, coupled with abusive storage temperatures of contaminated lettuce, were evaluated for their effect on the potential virulence of E. coli O157:H7. Shredded lettuce was inoculated with 5.58 and 3.98 log CFU E. coli O157:H7 per g and stored at 4 and 15°C, respectively, for up to 10 days. Lettuce was packaged under treatment A (modified atmosphere packaging conditions used for commercial fresh-cut produce, in gas-permeable film with N2), treatment B (near–ambient air atmospheric conditions in a gas-permeable film with microperforations), and treatment C (high-CO2 and low-O2 conditions in a gas-impermeable film). E. coli O157:H7 populations from each treatment were determined by enumeration of numbers on MacConkey agar containing nalidixic acid. RNA was extracted from packaged lettuce for analysis of expression of virulence factor genes stx2, eae, ehxA, iha, and rfbE. E. coli O157:H7 populations on lettuce at 4°C under all treatments decreased, but most considerably so under treatment B over 10 days. At 15°C, E. coli O157:H7 populations increased by at least 2.76 log CFU/g under all treatments. At 15°C, expression of eae and iha was significantly greater under treatment B than it was under treatments A and C on day 3. Similarly, treatment B promoted significantly higher expression of stx2, eae, ehxA, and rfbE genes on day 10, compared with treatments A and C at 15°C. Results indicate that storage under near–ambient air atmospheric conditions can promote higher expression levels of O157 virulence factors on lettuce, and could affect the severity of E. coli O157:H7 infections associated with leafy greens.

Growth potential of Escherichia coli O157:H7 on fresh-cut fruits (melon and pineapple) and vegetables (carrot and escarole) stored under different conditions

Food Control ◽  
2012 ◽  
Vol 27 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Maribel Abadias ◽  
Isabel Alegre ◽  
Marcia Oliveira ◽  
Rosa Altisent ◽  
Inmaculada Viñas
Keyword(s):  
Escherichia Coli ◽  
Growth Potential ◽  
Escherichia Coli O157 ◽  
Fresh Cut

Determination of Free Chlorine Concentrations Needed To Prevent Escherichia coli O157:H7 Cross-Contamination during Fresh-Cut Produce Wash†

2011 ◽  
Vol 74 (3) ◽  
pp. 352-358 ◽  
Author(s):  
YAGUANG LUO ◽  
XIANGWU NOU ◽  
YANG YANG ◽  
ISABEL ALEGRE ◽  
ELLEN TURNER ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Free Chlorine ◽  
Chlorine Concentration ◽  
Wash Water ◽  
Escherichia Coli O157 ◽  
Cross Contamination ◽  
E Coli ◽  
Wash Solution ◽  
Fresh Cut ◽  
Experimental Trials

This study was conducted to investigate the effect of free chlorine concentrations in wash water on Escherichia coli O157:H7 reduction, survival, and transference during washing of fresh-cut lettuce. The effectiveness of rewashing for inactivation of E. coli O157:H7 on newly cross-contaminated produce previously washed with solutions containing an insufficient amount of chlorine also was assessed. Results indicate that solutions containing a minimum of 0.5 mg/liter free chlorine were effective for inactivating E. coli O157:H7 in suspension to below the detection level. However, the presence of 1 mg/liter free chlorine in the wash solution before washing was insufficient to prevent E. coli O157:H7 survival and transfer during washing because the introduction of cut lettuce to the wash system quickly depleted the free chlorine. Although no E. coli O157:H7 was detected in the wash solution containing 5 mg/liter free chlorine before washing a mix of inoculated and uninoculated lettuce, low numbers of E. coli O157:H7 cells were detected on uninoculated lettuce in four of the seven experimental trials. When the prewash free chlorine concentration was increased to 10 mg/liter or greater, no E. coli O157:H7 transfer was detected. Furthermore, although rewashing newly cross-contaminated lettuce in 50 mg/liter free chlorine for 30 s significantly reduced (P = 0.002) the E. coli O157:H7 populations, it failed to eliminate E. coli O157:H7 on lettuce. This finding suggests that rewashing is not an effective way to correct for process failure, and maintaining a sufficient free chlorine concentration in the wash solution is critical for preventing pathogen cross-contamination.

Approaches toward Identification of Surrogates To Validate Antimicrobial Washes as Preventive Controls for Fresh-Cut Leafy Greens

2017 ◽  
Vol 80 (10) ◽  
pp. 1600-1604
Author(s):  
A. Shazer ◽  
D. Stewart ◽  
K. Deng ◽  
M. Tortorello
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Escherichia Coli O157 ◽  
Cross Contamination ◽  
Process Variables ◽  
Leafy Greens ◽  
Microbial Characteristics ◽  
Leaf Surfaces ◽  
Fresh Cut ◽  
Contamination Events

ABSTRACT In fresh-cut produce production, antimicrobials may be used during washing to control the risk of cross-contamination by microbial hazards. Surrogate microorganisms have long been used to validate processes, but none have been identified for validating the efficacy of antimicrobial washing of fresh-cut produce. The objective of this study was to develop procedures by which surrogates may be identified for use in validating the control of cross-contamination for fresh-cut lettuce operations. Four microbial characteristics, which may be important factors in cross-contamination events, were quantitatively evaluated in potential surrogate microorganisms for comparison to a reasonably foreseeable hazard, Escherichia coli O157:H7: sensitivity to chlorine in solution, sensitivity to chlorine on lettuce leaf surfaces, shedding from contaminated lettuce leaves into the water during washing, and cross-contamination from inoculated to uninoculated lettuce leaves during chorine washing. A procedure of practical quantitative experiments for comparing the characteristics reduced the original pool of 80 potential strains, which consisted of lactic acid bacteria, probiotics, and isolates obtained from lettuce enrichment cultures, to five strains: Lactobacillus plantarum, Pediococcus pentosaceus, probiotic 22C, and two lettuce enrichment isolates. These strains may be evaluated in additional studies involving comparisons to other reasonably foreseeable hazards and including other potential process variables that should be understood and controlled to prevent cross-contamination in fresh-cut lettuce operations.

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