scholarly journals The Effect Ultrasound and Surfactants on Nanobubbles Efficacy against Listeria innocua and Escherichia coli O157:H7, in Cell Suspension and on Fresh Produce Surfaces

Foods ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2154
Author(s):  
Shamil Rafeeq ◽  
Reza Ovissipour
Keyword(s):  
Escherichia Coli ◽  
Cell Suspension ◽  
Sodium Dodecyl ◽  
Listeria Innocua ◽  
Wash Water ◽  
Tween 20 ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Bacterial Removal ◽  
The Impact

Removing foodborne pathogens from food surfaces and inactivating them in wash water are critical steps for reducing the number of foodborne illnesses. In this study we evaluated the impact of surfactants on enhancing nanobubbles’ efficacy on Escherichia coli O157:H7, and Listeria innocua removal from spinach leaves. We evaluated the synergistic impact of nanobubbles and ultrasound on these two pathogens inactivation in the cell suspension. The results indicated that nanobubbles or ultrasound alone could not significantly reduce bacteria in cell suspension after 15 min. However, a combination of nanobubbles and ultrasonication caused more than 6 log cfu/mL reduction after 15 min, and 7 log cfu/mL reduction after 10 min of L. innocua and E. coli, respectively. Nanobubbles also enhanced bacterial removal from spinach surface in combination with ultrasonication. Nanobubbles with ultrasound removed more than 2 and 4 log cfu/cm2 of L. innocua and E. coli, respectively, while ultrasound alone caused 0.5 and 1 log cfu/cm2 of L. innocua and E. coli reduction, respectively. No reduction was observed in the solutions with PBS and nanobubbles. Adding food-grade surfactants (0.1% Sodium dodecyl sulfate-SDS, and 0.1% Tween 20), did not significantly enhance nanobubbles efficacy on bacterial removal from spinach surface.

scholarly journals Evaluation of Escherichia coli O157:H7 Translocation and Decontamination for Beef Vacuum-Packaged Subprimals Destined for Nonintact Use

2011 ◽  
Vol 74 (7) ◽  
pp. 1048-1053 ◽  
Author(s):  
JACOB L. LEMMONS ◽  
LISA M. LUCIA ◽  
MARGARET D. HARDIN ◽  
JEFFREY W. SAVELL ◽  
KERRI B. HARRIS
Keyword(s):  
Escherichia Coli ◽  
Wash Water ◽  
Escherichia Coli O157 ◽  
Applied Water ◽  
Inoculum Level ◽  
E Coli ◽  
Water Washing ◽  
Inoculation Site ◽  
Packaged Beef ◽  
The Impact

The translocation of Escherichia coli O157:H7 as well as the impact of water washing and partial or complete surface trimming as possible pathogen reduction strategies were evaluated for vacuum-packaged beef subprimals destined for nonintact use. Cap-on and cap-off beef top sirloin butts were inoculated with two levels of E. coli O157:H7: a high-inoculum level of approximately 104 CFU/cm2 and a low-inoculum level of approximately 102 CFU/cm2. Following inoculation, the subprimals were vacuum packaged and stored for 0, 14, or 28 days. Upon removal from storage, the following sites were evaluated: exterior of the bag, purge, the inoculation site on the subprimal, the area adjacent to the inoculation site, and the surface opposite from the inoculation site. The following treatments then were applied: water wash, water wash followed by full-surface trimming, water wash followed by partial-surface trimming, full-surface trimming, full-surface trimming followed by water wash, partial-surface trimming, and partial-surface trimming followed by water wash. For both high- and low-inoculated top sirloin butts, contamination of adjacent and opposite surfaces was found after vacuum packaging. Of the treatments applied, water washing alone was the least effective for both high- and low-inoculated subprimals. Full trimming, with or without a water wash, proved to be the most effective treatment used to reduce E. coli O157:H7 to nondetectable levels.

scholarly journals Impact of Vacuum Cooling on Escherichia coli O157:H7 Infiltration into Lettuce Tissue

2008 ◽  
Vol 74 (10) ◽  
pp. 3138-3142 ◽  
Author(s):  
Haiping Li ◽  
Mehrdad Tajkarimi ◽  
Bennie I. Osburn
Keyword(s):  
Escherichia Coli ◽  
Risk Assessment ◽  
Reduction Rate ◽  
Escherichia Coli O157 ◽  
Surface Sterilization ◽  
E Coli ◽  
Green Industry ◽  
Vacuum Cooling ◽  
The Impact

ABSTRACT Vacuum cooling is a common practice in the California leafy green industry. This study addressed the impact of vacuum cooling on the infiltration of Escherichia coli O157:H7 into lettuce as part of the risk assessment responding to the E. coli O157:H7 outbreaks associated with leafy green produce from California. Vacuum cooling significantly increased the infiltration of E. coli O157:H7 into the lettuce tissue (2.65E+06 CFU/g) compared to the nonvacuumed condition (1.98E+05 CFU/g). A stringent surface sterilization and quadruple washing could not eliminate the internalized bacteria from lettuce. It appeared that vacuuming forcibly changed the structure of lettuce tissue such as the stomata, suggesting a possible mechanism of E. coli O157:H7 internalization. Vacuuming also caused a lower reduction rate of E. coli O157:H7 in stored lettuce leaves than that for the nonvacuumed condition.

Efficacy of Chemical Treatments in Eliminating Salmonella and Escherichia coli O157:H7 on Scarified and Polished Alfalfa Seeds

2001 ◽  
Vol 64 (10) ◽  
pp. 1489-1495 ◽  
Author(s):  
SARAH L. HOLLIDAY ◽  
ALAN J. SCOUTEN ◽  
LARRY R. BEUCHAT
Keyword(s):  
Escherichia Coli ◽  
Chemical Treatment ◽  
Organic Material ◽  
Pathogenic Bacteria ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Mechanical Abrasion ◽  
Chemical Treatments ◽  
The Impact ◽  
Alfalfa Seeds

Alfalfa seeds are sometimes subjected to a scarification treatment to enhance water uptake, which results in more rapid and uniform germination during sprout production. It has been hypothesized that this mechanical abrasion treatment diminishes the efficacy of chemical treatments used to kill or remove pathogenic bacteria from seeds. A study was done to compare the effectiveness of chlorine (20,000 ppm), H2O2 (8%), Ca(OH)2 (1%), Ca(OH)2 (1%) plus Tween 80 (1%), and Ca(OH)2 (1%) plus Span 20 (1%) treatments in killing Salmonella and Escherichia coli O157:H7 inoculated onto control, scarified, and polished alfalfa seeds obtained from two suppliers. The influence of the presence of organic material in the inoculum carrier on the efficacy of sanitizers was investigated. Overall, treatment with 1% Ca(OH)2 was the most effective in reducing populations of the pathogens. Reduction in populations of pathogens on seeds obtained from supplier 1 indicate that chemical treatments are less efficacious in eliminating the pathogens on scarified seeds compared to control seeds. However, the effectiveness of chemical treatment in removing Salmonella and E. coli O157:H7 from seeds obtained from supplier 2 was not markedly affected by scarification or polishing. The presence of organic material in the inoculum carrier did not have a marked influence on the efficacy of chemicals in reducing populations of test pathogens. Additional lots of control, scarified, and polished alfalfa seeds of additional varieties need to be tested before conclusions can be drawn concerning the impact of mechanical abrasion on the efficacy of chemical treatment in removing or killing Salmonella and E. coli O157:H7.

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.

Efficacy of Commercial Produce Sanitizers against Nontoxigenic Escherichia coli O157:H7 during Processing of Iceberg Lettuce in a Pilot-Scale Leafy Green Processing Line

2013 ◽  
Vol 76 (11) ◽  
pp. 1838-1845 ◽  
Author(s):  
GORDON R. DAVIDSON ◽  
ANNEMARIE L. BUCHHOLZ ◽  
ELLIOT T. RYSER
Keyword(s):  
Escherichia Coli ◽  
Fluorescent Protein ◽  
Pilot Scale ◽  
Wash Water ◽  
Escherichia Coli O157 ◽  
Cross Contamination ◽  
E Coli ◽  
Iceberg Lettuce ◽  
Processing Line ◽  
Green Fluorescent

Chemical sanitizers are routinely used during commercial flume washing of fresh-cut leafy greens to minimize cross-contamination from the water. This study assessed the efficacy of five commercial sanitizer treatments against Escherichia coli O157:H7 on iceberg lettuce, in wash water, and on equipment during simulated commercial production in a pilot-scale processing line. Iceberg lettuce (5.4 kg) was inoculated to contain 106 CFU/g of a four-strain cocktail of nontoxigenic, green fluorescent protein–labeled, ampicillin-resistant E. coli O157:H7 and processed after 1 h of draining at ~22°C. Lettuce was shredded using a commercial slicer, step-conveyed to a flume tank, washed for 90 s using six different treatments (water alone, 50 ppm of peroxyacetic acid, 50 ppm of mixed peracid, or 50 ppm of available chlorine either alone or acidified to pH 6.5 with citric acid [CA] or T-128), and then dried using a shaker table and centrifugal dryer. Various product (25-g) and water (50-ml) samples collected during processing along with equipment surface samples (100 cm2) from the flume tank, shaker table, and centrifugal dryer were homogenized in neutralizing buffer and plated on tryptic soy agar. During and after iceberg lettuce processing, none of the sanitizers were significantly more effective (P ≤ 0.05) than water alone at reducing E. coli O157:H7 populations on lettuce, with reductions ranging from 0.75 to 1.4 log CFU/g. Regardless of the sanitizer treatment used, the centrifugal dryer surfaces yielded E. coli O157:H7 populations of 3.49 to 4.98 log CFU/100 cm2. Chlorine, chlorine plus CA, and chlorine plus T-128 were generally more effective (P ≤ 0.05) than the other treatments, with reductions of 3.79, 5.47, and 5.37 log CFU/ml after 90 s of processing, respectively. This indicates that chlorine-based sanitizers will likely prevent wash water containing low organic loads from becoming a vehicle for cross-contamination.

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.

Inactivation of Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes on Apples, Oranges, and Tomatoes by Lactic Acid with Hydrogen Peroxide

2002 ◽  
Vol 65 (1) ◽  
pp. 100-105 ◽  
Author(s):  
KUMAR S. VENKITANARAYANAN ◽  
CHIA-MIN LIN ◽  
HANNALORE BAILEY ◽  
MICHAEL P. DOYLE
Keyword(s):  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Chemical Treatment ◽  
Salmonella Enteritidis ◽  
Deionized Water ◽  
Wash Water ◽  
Escherichia Coli O157 ◽  
E Coli

The objective of this study was to develop a practical and effective method for inactivating or substantially reducing Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes on apples, oranges, and tomatoes. Apples, oranges, and tomatoes were spot-inoculated with five-strain mixtures of E. coli O157:H7, Salmonella Enteritidis, and L. monocytogenes near the stem end and were submerged in sterile deionized water containing 1.5% lactic acid plus 1.5% hydrogen peroxide for 15 min at 40°C. Inoculated samples treated with sterile deionized water at the same temperature and for the same duration served as controls. The bacterial pathogens on fruits subjected to the chemical treatment were reduced by >5.0 log10 CFU per fruit, whereas washing in deionized water decreased the pathogens by only 1.5 to 2.0 log10 CFU per fruit. Furthermore, substantial populations of the pathogens survived in the control wash water, whereas no E. coli O157:H7, Salmonella Enteritidis, or L. monocytogenes cells were detected in the chemical treatment solution. The sensory and qualitative characteristics of apples treated with the chemical wash solution were not adversely affected by the treatment. It was found that the treatment developed in this study could effectively be used to kill E. coli O157:H7, Salmonella Enteritidis, and L. monocytogenes on apples, oranges, and tomatoes at the processing or packaging level.

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.

Evaluation of an Enzyme-Linked Immunosorbent Assay, Direct Immunofluorescent Filter Technique, and Multiplex Polymerase Chain Reaction for Detection of Escherichia coli O157:H7 Seeded in Beef Carcass Wash Water†

1998 ◽  
Vol 61 (8) ◽  
pp. 934-938 ◽  
Author(s):  
PINA M. FRATAMICO ◽  
TERENCE P. STROBAUGH
Keyword(s):  
Escherichia Coli ◽  
Polymerase Chain Reaction ◽  
Multiplex Pcr ◽  
Multiplex Polymerase Chain Reaction ◽  
Wash Water ◽  
Enzyme Linked Immunosorbent Assay ◽  
Escherichia Coli O157 ◽  
Chain Reaction ◽  
E Coli ◽  
Polymerase Chain

In commercial beef processing, carcasses are customarily washed with water to remove physical and microbial contamination. Assaying the water that is shed from the carcasses after washing is a convenient method to determine whether the carcass is contaminated with Escherichia coli O157:H7 or other bacterial pathogens. E. coli O157:H7 was inoculated into carcass wash water at various levels and the bacteria were then concentrated by filtration. After collection of bacteria in the filter units, the nylon membranes were cut out and placed in tubes containing growth medium, and the tubes were mixed vigorously to dislodge the bacteria from the membranes. Prior to enrichment, samples were removed for testing by a multiplex polymerase chain reaction (PCR) and a direct immunofluorescent filter technique (DIFT). The remaining samples were subjected to 4-h enrichment culturing at 37°C, after which aliquots were removed for testing by multiplex PCR, DIFT, and an enzyme-linked immunosorbent assay (ELISA). Following 4-h enrichment culturing, E. coli O157:H7 was detected in wash water samples initially inoculated with ca. 100, 0.1, and 1 CFU/ml by ELISA, DIFT, and multiplex PCR, respectively. Testing of the wash water using the ELISA and the DIFT can be accomplished in less than 8 h. On the basis of these results, assaying carcass wash water by ELISA, DIFT, or multiplex PCR can be useful for detection of E. coli O157:H7 beef carcass contamination and can potentially be employed to identify carcasses for further processing to inactivate the organism.

Environmental Dust Exposure as a Factor Contributing to an Increase in Escherichia coli O157 and Salmonella Populations on Cattle Hides in Feedyards

2008 ◽  
Vol 71 (10) ◽  
pp. 2078-2081 ◽  
Author(s):  
M. F. MILLER ◽  
G. H. LONERAGAN ◽  
D. D. HARRIS ◽  
K. D. ADAMS ◽  
J. C. BROOKS ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Positive Sample ◽  
Dust Exposure ◽  
Most Probable Number ◽  
Escherichia Coli O157 ◽  
Probable Number ◽  
Airborne Dust ◽  
E Coli ◽  
Dust Generation ◽  
The Impact

A study was conducted to determine the impact of exposure to dust in the cattle load-out area in feedyards on pathogen contamination of cattle hides. A total of 250 cattle hides were sampled during summer and fall months, which are associated with elevated prevalence of Escherichia coli O157 in West Texas. Animals were removed from their home pens and restrained in a chute and sampled prior to exposure to dust generated as a result of a simulated loading exercise. The cattle hides were sampled again after exposure to the loading dust to determine total numbers of pathogens on cattle hides on leaving their home pen (before loading) and on cattle hides after exposure to the dust in the loading area. Air and dirt samples from the home pens and the cattle load-out area were also collected. The presence of E. coli O157 and Salmonella was determined in all the samples, and when a positive sample was identified, the total numbers of these bacteria present were enumerated. The total numbers of pathogens increased after dust exposure; Salmonella counts increased from 1.09 log most probable number (MPN)/cm2 to 1.74 log MPN/cm2 after exposure, and E. coli O157 counts increased from 0.80 to 2.35 log MPN/cm2 after sampling. E. coli O157 and Salmonella were recovered from the air samples during dust generation at 6.66 and 11.1%, respectively. Salmonella and E. coli O157 prevalence was not changed and was not associated with the exposure to the dust. Results indicate airborne dust generated as a result of cattle movement and loading could be an important determining factor in total numbers of pathogens recovered on cattle hides.

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