Fate of Escherichia coli O157:H7 and Other Coliforms in Commercial Mayonnaise and Refrigerated Salad Dressing

1995 ◽  
Vol 58 (1) ◽  
pp. 13-18 ◽  
Author(s):  
ERROL V. RAGHUBEER ◽  
JIM S. KE ◽  
MICHAEL L. CAMPBELL ◽  
RICHARD S. MEYER
Keyword(s):  
Escherichia Coli ◽  
Storage Temperature ◽  
Enterobacter Aerogenes ◽  
Antimicrobial Effect ◽  
Coliform Bacteria ◽  
Escherichia Coli O157 ◽  
Salad Dressing ◽  
E Coli ◽  
Survival Pattern ◽  
High Level

Commercial mayonnaise and refrigerated ranch salad dressing were inoculated at two levels with two strains of Escherichia coli O157:H7, a non-pathogenic E. coli, and the non-fecal coliform Enterobacter aerogenes. Results showed that at the high inoculation level (>106 colony forming units [CFU]/g) in mayonnaise stored at room temperature (ca. 22°C) both strains of O157:H7 were undetected at 96 h. At the high inoculation level, all strains of coliform bacteria tested survived longer in salad dressing stored at 4°C than in mayonnaise stored at 22°C. The O157:H7 strains were still present at low levels after 17 days. The survival time in the low-level inoculum (104CFU/g) study decreased, but the survival pattern in the two products was similar to that observed in the high-level inoculum study. Slight differences in survival among strains were observed. The greater antimicrobial effect of mayonnaise may be attributable to differences in pH, water activity (aw), nutrients, storage temperature, and the presence of lysozyme in the whole eggs used in the production of commercial mayonnaise. Coliform bacteria survived longer in refrigerated salad dressing than in mayonnaise particularly at the high-level inoculum. Both mayonnaise (pH 3.91) and salad dressing (pH 4.51) did not support the growth of any of the microorganisms even though survival was observed.

Bacteriophages reduce Escherichia coli O157:H7 levels in experimentally inoculated sheep

2009 ◽  
Vol 89 (2) ◽  
pp. 285-293 ◽  
Author(s):  
S J Bach ◽  
R P Johnson ◽  
K. Stanford ◽  
T A McAllister
Keyword(s):  
Escherichia Coli ◽  
Oral Administration ◽  
Coliform Bacteria ◽  
Escherichia Coli O157 ◽  
Fecal Shedding ◽  
Total Coliforms ◽  
E Coli ◽  
Oral Inoculation ◽  
Experimental Treatments ◽  
And Control

Bacteriophage biocontrol has potential as a means of mitigating the prevalence of Escherichia coli O157:H7 in ruminants. The efficacy of oral administration of bacteriophages for reducing fecal shedding of E. coli O157:H7 by sheep was evaluated using 20 Canadian Arcott rams (50.0 ± 3.0) housed in four rooms (n = 5) in a contained facility. The rams had ad libitum access to drinking water and a pelleted barley-based total mixed ration, delivered once daily. Experimental treatments consisted of administration of E. coli O157:H7 (O157), E. coli O157:H7+bacteriophages (O157+phage), bacteriophages (phage), and control (CON). Oral inoculation of the rams with 109 CFU of a mixture of four nalidixic acid-resistant strains of E. coli O157:H7 was performed on day 0. A mixture of 1010 PFU of bacteriophages P5, P8 and P11 was administered on days -2, -1, 0, 6 and 7. Fecal samples collected on 14 occasions over 21 d were analyzed for E. coli O157:H7, total E. coli, total coliforms and bacteriophages. Sheep in treatment O157+phage shed fewer (P < 0.05) E. coli O157:H7 than did sheep in treatment O157. Populations of total coliforms and total E. coli were similar (P < 0.05) among treatments, implying that bacteriophage lysis of non-target E. coli and coliform bacteria in the gastrointestinal tract did not occur. Bacteriophage numbers declined rapidly over 21 d, which likely reduced the chance of collision between bacteria and bacteriophage. Oral administration of bacteriophages reduced shedding of E. coli O157:H7 by sheep, but a delivery system that would protect bacteriophages during passage through the intestine may increase the effectiveness of this strategy as well as allow phage to be administered in the feed.Key words: Escherichia coli O157:H7, bacteriophage, sheep, environment, coliforms

Effects of Water Source, Dilution, Storage, and Bacterial and Fecal Loads on the Efficacy of Electrolyzed Oxidizing Water for the Control of Escherichia coli O157:H7

2004 ◽  
Vol 67 (7) ◽  
pp. 1377-1383 ◽  
Author(s):  
S. M. L. STEVENSON ◽  
S. R. COOK ◽  
S. J. BACH ◽  
T. A. McALLISTER
Keyword(s):  
Escherichia Coli ◽  
Bactericidal Activity ◽  
Storage Temperature ◽  
Uv Light ◽  
Tap Water ◽  
Organic Matter Content ◽  
Water Source ◽  
Deionized Water ◽  
Escherichia Coli O157 ◽  
E Coli

To evaluate the potential of using electrolyzed oxidizing (EO) water for controlling Escherichia coli O157:H7 in water for livestock, the effects of water source, electrolyte concentration, dilution, storage conditions, and bacterial or fecal load on the oxidative reduction potential (ORP) and bactericidal activity of EO water were investigated. Anode and combined (7:3 anode:cathode, vol/vol) EO waters reduced the pH and increased the ORP of deionized water, whereas cathode EO water increased pH and lowered ORP. Minimum concentrations (vol/vol) of anode and combined EO waters required to kill 104 CFU/ml planktonic suspensions of E. coli O157:H7 strain H4420 were 0.5 and 2.0%, respectively. Cathode EO water did not inhibit H4420 at concentrations up to 16% (vol/vol). Higher concentrations of anode or combined EO water were required to elevate the ORP of irrigation or chlorinated tap water compared with that of deionized water. Addition of feces to EO water products (0.5% anode or 2.0% combined, vol/vol) significantly reduced (P &lt; 0.001) their ORP values to &lt;700 mV in all water types. A relationship between ORP and bactericidal activity of EO water was observed. The dilute EO waters retained the capacity to eliminate a 104 CFU/ml inoculation of E. coli O157:H7 H4420 for at least 70 h regardless of exposure to UV light or storage temperature (4 versus 24°C). At 95 h and beyond, UV exposure reduced ORP, significantly more so (P &lt; 0.05) in open than in closed containers. Bactericidal activity of EO products (anode or combined) was lost in samples in which ORP value had fallen to ≤848 mV. When stored in the dark, the diluted EO waters retained an ORP of &gt;848 mV and bactericidal efficacy for at least 125 h; with refrigeration (4°C), these conditions were retained for at least 180 h. Results suggest that EO water may be an effective means by which to control E. coli O157:H7 in livestock water with low organic matter content.

Antibacterial Effect of Monocaprylin on Escherichia coli O157:H7 in Apple Juice

2005 ◽  
Vol 68 (9) ◽  
pp. 1895-1899 ◽  
Author(s):  
MANOJ KUMAR MOHAN NAIR ◽  
HANEM ABOUELEZZ ◽  
THOMAS HOAGLAND ◽  
KUMAR VENKITANARAYANAN
Keyword(s):  
Escherichia Coli ◽  
Apple Juice ◽  
Antibacterial Effect ◽  
Storage Temperature ◽  
Escherichia Coli O157 ◽  
Organoleptic Properties ◽  
E Coli ◽  
Low Concentrations ◽  
Storage Temperatures ◽  
Control Samples

The antibacterial effect of low concentrations of monocaprylin on Escherichia coli O157:H7 in apple juice was investigated. Apple juice alone (control) or containing 2.5 mM (0.055%) or 5 mM monocaprylin was inoculated with a five-strain mixture of E. coli O157:H7 at ~6.0 log CFU/ml. The juice samples were stored at 23 or 4°C for 14 or 21 days, respectively, and the population of E. coli O157:H7 was determined on tryptic soy agar plates supplemented with 0.6% yeast extract. At both storage temperatures, the population of E. coli O157:H7 in monocaprylin-supplemented juice samples was significantly lower (P &lt; 0.05) than that in the control samples. The concentration of monocaprylin and the storage temperature had a significant effect on the inactivation of E. coli O157:H7 in apple juice. Monocaprylin at 5 mM was significantly more effective than 2.5 mM monocaprylin for killing E. coli O157:H7 in apple juice. Inactivation of E. coli O157:H7 by monocaprylin was more pronounced in juice stored at 23°C than in the refrigerated samples. Results of this study indicated that monocaprylin is effective for killing E. coli O157:H7 in apple juice, but detailed sensory studies are needed to determine the organoleptic properties of apple juice containing monocaprylin.

scholarly journals Escherichia coli O157:H7 in Drin Prevalence of Escherichia coli O157:H7 in Drink from Different Food Premises in Kota Samarahan Sarawak

2019 ◽  
Vol 2 (2) ◽  
pp. a13-19
Author(s):  
ELEXSON NILLIAN ◽  
AMIZA NUR ◽  
DIYANA NUR ◽  
AMIRAH ZAKIRAH ◽  
GRACE BEBEY
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Coliform Bacteria ◽  
Most Probable Number ◽  
Plain Water ◽  
Escherichia Coli O157 ◽  
Probable Number ◽  
E Coli ◽  
Preventive Actions ◽  
Stx1 Gene

Contamination of drinks with E. coli O157:H7 served in food premises such as restaurants can cause haemorrhagic colitis and haemolytic uremic syndrome to humans. The presence or absence of faecal pathogen was demonstrated using coliform group as indicator microorganisms. Therefore, this study was conducted to detect the presence of E. coli O157:H7 in drinking water from food restaurant premise in Kota Samarahan and Kuching to ensure safe and potable drinking water is served to the consumer. A total of thirty (n=30) drink samples including six types of each of the samples are cold plain water, iced tea, iced milo, syrup and iced milk tea. Most Probable Number (MPN) procedure was used in this study to enumerate the MPN values of coliform bacteria in each drink collected. A total of 53.33% (16/30) of the drink samples showed positive E. coli detection. Then, the PCR assay showed 6.25% (one out of 16 isolates) samples were positive and carried stx1 gene produced by E. coli O157:H7 in iced milo sample types. This study showed the drinks collected from food premises was contaminated with faecal contamination, which was not safe to drink by the consumer. Therefore, preventive actions should be taken to prevent foodborne illness outbreak in future

Use of the Systems Approach To Determine the Fate of Escherichia coli O157:H7 on Fresh Lettuce and Spinach

2009 ◽  
Vol 72 (7) ◽  
pp. 1560-1568 ◽  
Author(s):  
HELGA J. DOERING ◽  
MARK A. HARRISON ◽  
RUTH A. MORROW ◽  
WILLIAM C. HURST ◽  
WILLIAM L. KERR
Keyword(s):  
Escherichia Coli ◽  
Systems Approach ◽  
Storage Temperature ◽  
Storage Period ◽  
Categorical Variables ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Field Temperature ◽  
Before And After ◽  
Handling Practices

Lettuce and spinach inoculated with Escherichia coli O157:H7 were processed and handled in ways that might occur in commercial situations, including variations in holding times before and after product cooling, transportation conditions and temperatures, wash treatments, and product storage temperatures and times. Populations of background microflora and E. coli O157:H7 were enumerated after each step in the system. Data analysis was done to predict response variables with a combination of independent categorical variables. Field temperature, time before cooling, and wash treatment significantly affected E. coli O157:H7 populations on both products. The lowest populations of E. coli O157:H7 were encountered when precool time was minimal, lettuce was washed with chlorine, and storage temperature was 4°C. For lettuce, field and transportation temperature were not important once the storage period started, whereas after 2 days E. coli O157:H7 populations on packaged baby spinach were not affected by field temperature. On chopped iceberg lettuce and whole leaf spinach that was packaged and stored at 4°C, E. coli O157:H7 contamination could still be detected after typical handling practices, although populations decreased from initial levels in many cases by at least 1.5 log units. In abusive cases, where populations increased, the product quality quickly deteriorated. Although E. coli O157:H7 levels decreased on products handled and stored under recommended conditions, survivors persisted. This study highlights practices that may or may not affect the populations of E. coli O157:H7 on the final product.

Fate of Escherichia coli O157:H7 in the Presence of Indigenous Microorganisms on Commercially Packaged Baby Spinach, as Impacted by Storage Temperature and Time†

2009 ◽  
Vol 72 (10) ◽  
pp. 2038-2045 ◽  
Author(s):  
YAGUANG LUO ◽  
QIANG HE ◽  
JAMES L. McEVOY ◽  
WILLIAM S. CONWAY
Keyword(s):  
Escherichia Coli ◽  
Product Quality ◽  
Elevated Temperatures ◽  
Storage Temperature ◽  
Escherichia Coli O157 ◽  
Indigenous Microorganisms ◽  
E Coli ◽  
Psychrotrophic Bacteria ◽  
Survival And Growth

This study investigated the effect of storage temperature and time on the survival and growth of Escherichia coli O157:H7, the growth of indigenous microorganisms, and the changes in product quality of packaged baby spinach. Commercial packages of spinach within 2 days of processing were cut open at one end, sprayed with fine mists of E. coli O157:H7 inoculum, resealed, and then stored at 1, 5, 8, and 12°C for 12 days until their labeled best-if-used-by dates. Microbial enumeration and product quality evaluation were conducted on day(s) 0, 3, 6, 9, and 12 postinoculation. Spinach held at 12°C supported significant (P &lt; 0.001) E. coli O157:H7 growth, with a 1.0-log CFU/g increase within 3 days postinoculation, which was followed by additional growth during continued storage. E. coli O157:H7 grew slowly when held at 8°C, with a significant (P &lt; 0.01) level of growth reached after 6 days of storage. However, on products held at 1 and 5°C, E. coli O157:H7 populations declined significantly (P &lt; 0.01 and P &lt; 0.001, respectively) within 3 days of storage. Aerobic mesophilic bacteria, psychrotrophic bacteria, and yeast and mold populations increased significantly at all storage temperatures, with more growth on products held at elevated temperatures. Product quality scores remained high within the first 6 days of storage, with a sharp decline noted on samples held at 12°C on day 9. Results suggest that E. coli O157:H7 can grow significantly on commercially packaged spinach held at 8°C or above before significant product quality deterioration occurs.

Shellac Formulations To Reduce Epiphytic Survival of Coliform Bacteria on Citrus Fruit Postharvest†

2001 ◽  
Vol 64 (11) ◽  
pp. 1756-1760 ◽  
Author(s):  
RAYMOND G. McGUIRE ◽  
ROBERT D. HAGENMAIER
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Limit Of Detection ◽  
Citrus Fruit ◽  
Enterobacter Aerogenes ◽  
Coliform Bacteria ◽  
Undetectable Level ◽  
Neutral Solution ◽  
E Coli ◽  
Epiphytic Survival

Survival of the coliform bacteria Enterobacter aerogenes and Escherichia coli was monitored in a neutral carboxyme-thylcellulose formulation and in shellac formulations with various pH and concentrations of ethanol and the preservative paraben; populations were subsequently measured from the surface of citrus fruit coated with these formulations. Numbers of the two bacteria increased over 24 h from 106 CFU/ml to approximately 108 CFU/ml in the carboxymethylcellulose solution, but over this time numbers remained little changed in the neutral solution of shellac. The Enterobacter was more tolerant of alcohol over a 3-h period; although its numbers in a shellac solution with 10% ethanol dropped from more than 106 CFU/ml to just over 103 CFU/ml, E. coli and a third species, Klebsiella pneumoniae, declined toward the limit of detection (5 CFU/ml) during this time. The addition of morpholine to increase the formulation pH to 9.0 caused numbers of bacteria to plummet to an undetectable level within 30 to 60 min. On Ruby Red grapefruit and Valencia oranges in storage at 13°C numbers of E. aerogenes and E. coli declined over 2 weeks from 105 CFU/cm2 to less than 2.5 × 101, but most of the loss in numbers occurred within 1 day. Numbers remained significantly less on shellacked fruit compared with those applied in the carboxymethylcellulose coating, and a shellac coating prepared from a pH 9 solution was more toxic to these species than one in which 12% ethanol had been added to the neutral formulation. The addition of the preservative paraben in the basic shellac was further inhibitory.

Comparison of VRB and VRB-2 Agars for Recovery of Stressed Coliforms From Stored Acidified Half-and-Half1

1982 ◽  
Vol 45 (7) ◽  
pp. 584-585 ◽  
Author(s):  
C. L. REBER ◽  
R. T. MARSHALL
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Enterobacter Aerogenes ◽  
Coliform Bacteria ◽  
E Coli ◽  
Culture Viability

Half-and-half was acidified with delta-gluconolactone, inoculated with three species of coliform bacteria, stored for 31 days at 5 °C, and examined for numbers of viable coliforms on VRB and VRB-2 agars. Loss of culture viability was logarithmic with recovery of 50 and 10% of initial numbers on days 7 and 30, respectively. Escherichia coli had significantly more recoverable injured cells than did Enterobacter aerogenes or Klebsiella pneumoniae. As time of storage increased, the proportion of injured to noninjured cells also increased. However, the maximal number of injured cells was on the thirteenth day of storage of E. coli-inoculated product. VRB-2 agar averaged 20% higher in productivity than VRB agar.

scholarly journals Longitudinal Study of Escherichia coli O157:H7 in a Beef Cattle Feedlot and Role of High-Level Shedders in Hide Contamination

2009 ◽  
Vol 75 (20) ◽  
pp. 6515-6523 ◽  
Author(s):  
Terrance M. Arthur ◽  
James E. Keen ◽  
Joseph M. Bosilevac ◽  
Dayna M. Brichta-Harhay ◽  
Norasak Kalchayanand ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Longitudinal Study ◽  
Beef Cattle ◽  
Intervention Studies ◽  
High Density ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
High Level ◽  
Cattle Feedlot

ABSTRACT The objectives of the study described here were (i) to investigate the dynamics of Escherichia coli O157:H7 fecal and hide prevalence over a 9-month period in a feedlot setting and (ii) to determine how animals shedding E. coli O157:H7 at high levels affect the prevalence and levels of E. coli O157:H7 on the hides of other animals in the same pen. Cattle (n = 319) were distributed in 10 adjacent pens, and fecal and hide levels of E. coli O157:H7 were monitored. When the fecal pen prevalence exceeded 20%, the hide pen prevalence was usually (25 of 27 pens) greater than 80%. Sixteen of 19 (84.2%) supershedder (>104 CFU/g) pens had a fecal prevalence greater than 20%. Significant associations with hide and high-level hide (≥40 CFU/100 cm2) contamination were identified for (i) a fecal prevalence greater than 20%, (ii) the presence of one or more high-density shedders (≥200 CFU/g) in a pen, and (iii) the presence of one or more supershedders in a pen. The results presented here suggest that the E. coli O157:H7 fecal prevalence should be reduced below 20% and the levels of shedding should be kept below 200 CFU/g to minimize the contamination of cattle hides. Also, large and unpredictable fluctuations within and between pens in both fecal and hide prevalence of E. coli O157:H7 were detected and should be used as a guide when preharvest studies, particularly preharvest intervention studies, are designed.

Viability of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in Yellow Fat Spreads as Affected by Storage Temperature

2003 ◽  
Vol 66 (4) ◽  
pp. 549-558 ◽  
Author(s):  
SARAH L. HOLLIDAY ◽  
LARRY R. BEUCHAT
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Storage Temperature ◽  
Salt Content ◽  
Inactivation Kinetics ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Inhibition Of Growth ◽  
Time Required ◽  
Kinetics Of

A study was conducted to characterize the survival and inactivation kinetics of a five-serotype mixture of Salmonella (6.23 to 6.55 log10 CFU per 3.5-ml or 4-g sample), a five-strain mixture of Escherichia coli O157:H7 (5.36 to 6.14 log10 CFU per 3.5-ml or 4-g sample), and a six-strain mixture of Listeria monocytogenes (5.91 to 6.18 log10 CFU per 3.5-ml or 4-g sample) inoculated into seven yellow fat spreads (one margarine, one butter-margarine blend, and five dairy and nondairy spreads and toppings) after formulation and processing and stored at 4.4, 10, and 21°C for up to 94 days. Neither Salmonella nor E. coli O157:H7 grew in any of the test products. The time required for the elimination of each pathogen depended on the product and the storage temperature. Death was more rapid at 21°C than at 4.4 or 10°C. Depending on the product, the time required for the elimination of viable cells at 21°C ranged from 5 to 7 days to &gt;94 days for Salmonella, from 3 to 5 days to 28 to 42 days for E. coli O157:H7, and from 10 to 14 days to &gt;94 days for L. monocytogenes. Death was most rapid in a water-continuous spray product (pH 3.66, 4.12% salt) and least rapid in a butter-margarine blend (pH 6.66, 1.88% salt). E. coli O157:H7 died more rapidly than did Salmonella or L. monocytogenes regardless of storage temperature. Salmonella survived longer in high-fat (≥61%) products than in products with lower fat contents. The inhibition of growth is attributed to factors such as acidic pH, salt content, the presence of preservatives, emulsion characteristics, and nutrient deprivation. L. monocytogenes did not grow in six of the test products, but its population increased between 42 and 63 days in a butter-margarine blend stored at 10°C and between 3 and 7 days when the blend was stored at 21°C. On the basis of the experimental parameters examined in this study, traditional margarine and spreads not containing butter are not “potentially hazardous foods” in that they do not support the growth of Salmonella, E. coli O157:H7, or L. monocytogenes.

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