Impact of Wash Water Quality on Sensory and Microbial Quality, Including Escherichia coli Cross-Contamination, of Fresh-Cut Escarole

2008 ◽  
Vol 71 (12) ◽  
pp. 2514-2518 ◽  
Author(s):  
ANA ALLENDE ◽  
MARIA V. SELMA ◽  
FRANCISCO LÓPEZ-GÁLVEZ ◽  
RAQUEL VILLAESCUSA ◽  
MARÍA I. GIL
Keyword(s):  
Escherichia Coli ◽  
Water Quality ◽  
Sensory Quality ◽  
Wash Water ◽  
Microbial Load ◽  
Contamination Level ◽  
Cross Contamination ◽  
Inoculum Level ◽  
E Coli ◽  
Fresh Cut

The influence of wash water quality on the microbial load and sensory quality of fresh-cut escarole was evaluated. Additionally, the degree of Escherichia coli cross-contamination between inoculated and uninoculated products after washing was also studied. Three types of wash water, i.e., potable water, diluted recirculated water, and recirculated water, containing different microbial counts and organic loads, were used. Results showed that microbial load (P > 0.02) and sensory quality (P > 0.625) of the product were not influenced by the water quality after washing and storage. Cross-contamination between inoculated and uninoculated products was observed after washing, as there was significant transmission of E. coli cells from the product to the wash water (P < 0.001). When fresh-cut escarole was contaminated at a high inoculum level (5.1 log CFU/g), wash water quality influenced the level of cross-contamination, as the highest E. coli load (P < 0.001) was shown in uninoculated fresh-cut escarole washed with recirculated water. However, when fresh-cut escarole was contaminated at a low inoculum level (3.2 log CFU/g), the wash water quality did not influence the level of cross-contamination, as E. coli slightly increased, although not at a statistically significant level, after the uninoculated product was washed with recirculated water (P > 0.035). Therefore, the contamination level may impact the effectiveness of water quality to reduce pathogen concentrations. It was clearly observed that cross-contamination of fresh-cut escarole with E. coli occurs, thereby suggesting that small amounts of contamination could impact the overall product and indicating the necessity of using wash water sanitizers to eliminate pathogens.

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.

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.

Behavior of Shiga Toxigenic Escherichia coli Relevant to Lettuce Washing Processes and Consideration of Factors for Evaluating Washing Process Surrogates

2014 ◽  
Vol 77 (11) ◽  
pp. 1860-1867 ◽  
Author(s):  
KAIPING DENG ◽  
XUE WANG ◽  
LI-HAN YEN ◽  
HONGLIU DING ◽  
MARY LOU TORTORELLO
Keyword(s):  
Escherichia Coli ◽  
Bacterial Species ◽  
Wash Water ◽  
Lag Phase ◽  
Phenotypic Traits ◽  
Cross Contamination ◽  
Process Validation ◽  
E Coli ◽  
Hazard Characterization ◽  
Washing Process

Postharvest processes for fresh produce commonly include washing in water containing antimicrobial chemicals, such as chlorine; however, if the antimicrobials are not present in sufficient levels, washing can promote the spread of contamination that might be present. To understand cross-contamination risk during washing, we tested a collection of Shiga toxigenic Escherichia coli (STEC), including O157:H7 and other non-O157 strains, for certain traits during washing of fresh-cut lettuce, i.e., sensitivity to sublethal chlorine levels and ability to cross-contaminate (detach from and attach to) lettuce in the presence of sublethal chlorine levels. Nonpathogenic E. coli Nissle 1917 (EcN) and Pediococcus pentosaceus lactic acid bacterial species (LAB) were included as potential washing process validation surrogates. As measured by extension of the lag phase of growth in media containing 0.15 ppm of chlorine, chlorine sensitivity varied among the STECs. Cross-contamination was assessed by evaluating transfer of bacteria from inoculated to uninoculated leaves during washing. Without chlorine, similar transfer to wash water and uninoculated leaves was shown. In 1 ppm of chlorine, cross-contamination was not detected with most strains, except for the substantial transfer by a STEC O111 strain and EcN in some replicates. Strain O111 and EcN showed less inactivation in 0.25 ppm of chlorine water compared with O157 (P < 0.05). LAB showed similar transfer and similar chlorine inactivation to O157. Considering together the sublethal chlorine sensitivity and detachment/attachment traits, neither EcN nor LAB displayed optimal characteristics as washing process surrogates for the STEC strains, although further evaluation is needed. This work demonstrated a range of behaviors of STEC strains during lettuce washing and may be helpful in hazard characterization, identifying factors to consider for evaluating washing process efficacy, and identifying phenotypic traits to select surrogates to validate washing processes.

Quantitative study of cross-contamination with Escherichia coli, E. coli O157, MS2 phage and murine norovirus in a simulated fresh-cut lettuce wash process

Food Control ◽  
2014 ◽  
Vol 37 ◽  
pp. 218-227 ◽  
Author(s):  
K. Holvoet ◽  
A. De Keuckelaere ◽  
I. Sampers ◽  
S. Van Haute ◽  
A. Stals ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Quantitative Study ◽  
Cross Contamination ◽  
Murine Norovirus ◽  
E Coli ◽  
Fresh Cut

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 Monitoring of transfer and internalization of Escherichia coli from inoculated knives to fresh cut cucumbers (Cucumis sativus L.) using bioluminescence imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yeting Sun ◽  
Xiaoyan Zhao ◽  
Xiulan Xu ◽  
Yue Ma ◽  
Hongyang Guan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bioluminescence Imaging ◽  
Storage Period ◽  
Cross Contamination ◽  
Cucumis Sativus L ◽  
Industrial Environment ◽  
E Coli ◽  
Fresh Cut ◽  
And Storage ◽  
Contaminated Area

AbstractSlicing may cause the risk of cross-contamination in cucumber. In this study, knife inoculated with Escherichia coli (E. coli) was used to cut cucumbers, bioluminescence imaging (BLI) was used to visualize the possible distribution and internalization of E. coli during cutting and storage. Results showed that the initial two slices resulted in greater bacterial transfer. The bacterial transfer exhibited a fluctuating decay trend, E. coli was most distributed at the initial cutting site. The contaminated area on the surface of cucumber slices decreased during the storage period, which can be attributed to the death and internalization of E. coli. The maximum internalization distance of E. coli was about 2–3 mm, and did not further spread after 30 min from inoculation. Hence, our results provide useful information for risk management in both home and industrial environment.

Transfer of Escherichia coli O157:H7 to Iceberg Lettuce via Simulated Field Coring

2009 ◽  
Vol 72 (3) ◽  
pp. 465-472 ◽  
Author(s):  
PETER J. TAORMINA ◽  
LARRY R. BEUCHAT ◽  
MARILYN C. ERICKSON ◽  
LI MA ◽  
GUODONG ZHANG ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Escherichia Coli O157 ◽  
Cross Contamination ◽  
Inoculum Level ◽  
E Coli ◽  
Iceberg Lettuce ◽  
Harvesting Technique ◽  
Untreated Water ◽  
Simulated Field ◽  
Contaminated Field

The field-core (cut and core) harvesting technique used for iceberg lettuce was evaluated as a potential means of cross-contamination with Escherichia coli O157:H7. Chlorinated water treatment was evaluated for its efficacy in removing or inactivating the pathogen on the blade portion of the field coring device and on cored lettuce. Field coring devices inoculated by immersing blades in soil containing E. coli O157:H7 at 3.74 or 6.57 log CFU/g contained 3.13 and 4.97 log CFU per blade, respectively. Treatment of inoculated field coring device blades by immersing in chlorinated water (200 μg/ml total chlorine) for 10 s resulted in a reduction of 1.56 log CFU per blade, which was 1.42 log CFU per blade greater than that achieved using water, but insufficient to eliminate the pathogen on blades. Field coring devices inoculated by contacting soil containing E. coli O157:H7 at 2.72 and 1.67 log CFU/g, then repeatedly used to cut and core 10 lettuce heads, transferred the pathogen to 10 and 5 consecutively processed heads, respectively. Lettuce cores remained positive for the pathogen after spraying with 100 μg/ml free chlorine for 120 s at 2.81 kg/cm2 (40 lb/in2), regardless of the inoculum level. The number of E. coli O157:H7 recovered from inoculated lettuce cores treated for 10 s with chlorine was significantly (P ≤ 0.05) different from the number recovered from tissues treated with water. Dipping contaminated field coring devices in chlorinated water may not be effective in killing the pathogen and controlling cross-contamination from head to head. Spraying contaminated lettuce with chlorinated or untreated water reduces but does not eliminate E. coli O157:H7.

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.

Growth of Selected Cross-Contaminating Bacterial Pathogens on Beef and Fish at 15 and 35°C+

1994 ◽  
Vol 57 (4) ◽  
pp. 337-340 ◽  
Author(s):  
AJIBOLA O. FAPOHUNDA ◽  
KENNETH W. MCMILLIN ◽  
DOUGLAS L. MARSHALL ◽  
W. M. WAITES
Keyword(s):  
Escherichia Coli ◽  
Clostridium Perfringens ◽  
Aeromonas Hydrophila ◽  
Growth Response ◽  
Cross Contamination ◽  
Limited Growth ◽  
E Coli ◽  
Fish Samples ◽  
Conditioning Temperature ◽  
The Tropics

Isolates of Escherichia coli and Clostridium perfringens from beef and Aeromonas hydrophila from fish were examined for their ability to survive and grow as cross-contaminates on nonnative tissues at simulated ambient (35°C) and aging/conditioning (15°C) temperatures of handling and retailing found in the tropics. Growth of all isolates over a 10-h period was greater (P < 0.05) on their native tissues at both temperatures. The aging/conditioning temperature effectively limited growth of E. coli and A. hydrophila to less than l-logl0 CFU/g and prevented growth of C. perfringens on beef and fish samples. All three isolates demonstrated characteristic mesophilic growth response on both tissues at 35°C during the 10-h retail period. The study suggests that two muscle food products could be jointly handled to efficiently use available storage/haulage capacity in tropical countries. Potential savings in space, labor and energy would be made if cross-contamination between the two products is minimized by available packaging and sanitizing technologies.

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.

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