High-Pressure Resistance Variation of Escherichia coli O157:H7 Strains and Salmonella Serovars in Tryptic Soy Broth, Distilled Water, and Fruit Juice

2007 ◽  
Vol 70 (9) ◽  
pp. 2078-2083 ◽  
Author(s):  
BROOKE M. WHITNEY ◽  
ROBERT C. WILLIAMS ◽  
JOSEPH EIFERT ◽  
JOSEPH MARCY
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
Orange Juice ◽  
High Pressure Processing ◽  
Distilled Water ◽  
Escherichia Coli O157 ◽  
Bacterial Populations ◽  
E Coli ◽  
Log Reduction ◽  
Salmonella Serovars

The effect of high pressure on the log reduction of six strains of Escherichia coli O157:H7 and five serovars of Salmonella enterica was investigated in tryptic soy broth, sterile distilled water, and commercially sterile orange juice (for Salmonella) and apple cider (for E. coli). Samples were subjected to high-pressure processing treatment at 300 and 550 MPa for 2 min at 6°C. Samples were plated onto tryptic soy agar directly after pressurization and after being held for 24 h at 4°C. At 300 MPa, little effect was seen on E. coli O157:H7 strains, while Salmonella serovars varied in resistance, showing reductions between 0.26 and 3.95 log CFU/ml. At 550 MPa, E. coli O157:H7 strains exhibited a range of reductions (0.28 to 4.39 log CFU/ml), while most Salmonella populations decreased beyond the detection limit (>5-log CFU/ml reduction). The most resistant strains tested were E. coli E009 and Salmonella Agona. Generally, bacterial populations in fruit juices showed larger decreases than did populations in tryptic soy broth and distilled water. E. coli O157:H7 cultures held for 24 h at 4°C after treatment at 550 MPa showed a significant log decrease as compared with cultures directly after treatment (P ≤ 0.05), while Salmonella serovars did not show this significant decrease (P > 0.05). All Salmonella serovars tested in orange juice treated at 550 MPa for 2 min at 6°C and held for 24 h showed a >5-log decrease, while E. coli O157:H7 strains require a higher pressure, higher temperature, longer pressurization, or a chemical additive to achieve a 5-log decrease.

Survival of Escherichia coli O157:H7 during Storage in Pressure-Treated Orange Juice

1999 ◽  
Vol 62 (9) ◽  
pp. 1038-1040 ◽  
Author(s):  
M. LINTON ◽  
J. M. J. McCLEMENTS ◽  
M. F. PATTERSON
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
Orange Juice ◽  
Ambient Pressure ◽  
Storage Period ◽  
High Pressure Processing ◽  
Escherichia Coli O157 ◽  
Pressure Treatment ◽  
E Coli ◽  
Time Required

The effect of a high-pressure treatment on the survival of a pressure-resistant strain of Escherichia coli O157:H7 (NCTC 12079) in orange juice during storage at 3°C was investigated over the pH range of 3.4 to 5.0. The pH of shelf-stable orange juice was adjusted to 3.4, 3.6, 3.9, 4.5, and 5.0 and inoculated with 108 CFU ml−1 of E. coli O157:H7. The orange juice was then pressure treated at 400 MPa for 1 min at 10°C or was held at ambient pressure (as a control). Surviving E. coli O157: H7 cells were enumerated at 1-day intervals during a storage period of 25 days at 3°C. Survival of E. coli O157:H7 during storage was dependent on the pH of the orange juice. The application of high pressure prior to storage significantly increased the susceptibility of E. coli O157:H7 to high acidity. For example, after pressure treatment, the time required for a 5-log decrease in cell numbers was reduced from 13 to 3 days at pH 3.4, from 16 to 6 days at pH 3.6, and from >25 to 8 days at pH 3.9. It is evident that the use of high-pressure processing of orange juice in order to increase the juice's shelf-life and to inactivate pathogens has the added advantage that it sensitizes E. coli O157:H7 to the high acid conditions found in orange juice, which results in the survival of significantly fewer E. coli O157:H7 during subsequent refrigerated storage.

Inactivation of Escherichia coli O157:H7 in Orange Juice Using a Combination of High Pressure and Mild Heat

1999 ◽  
Vol 62 (3) ◽  
pp. 277-279 ◽  
Author(s):  
M. LINTON ◽  
J. M. J. McCLEMENTS ◽  
M. F. PATTERSON
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
Resistant Strain ◽  
Orange Juice ◽  
Escherichia Coli O157 ◽  
Pressure Treatment ◽  
Processing Conditions ◽  
E Coli ◽  
Mild Heat ◽  
Ph Range

The effect of high pressure on the survival of a pressure-resistant strain of Escherichia coli O157:H7 (NCTC 12079) in orange juice was investigated over the pH range 3.4 to 5.0. The pH of commercial, sterile orange juice was adjusted to 3.4, 3.6, 3.9, 4.5, or 5.0. The juice was then inoculated with 108 CFU ml−1 of E. coli O157:H7. The inoculated orange juice was subjected to pressure treatments of 400, 500, or 550 MPa at 20°C or 30°C to determine the conditions that would give a 6-log10 inactivation of E. coli O157:H7. A pressure treatment of 550 MPa for 5 min at 20°C produced this level of kill at pH 3.4, 3.6, 3.9, and 4.5 but not at pH 5.0. Combining pressure treatment with mild heat (30°C) did result in a 6-log10 inactivation at pH 5.0. Thus, the processing conditions (temperature and time) must be considered when pressure-treating orange juice to ensure microbiological safety.

scholarly journals Lethality Prediction for Escherichia Coli O157:H7 and Uropathogenic E. coli in Ground Chicken Treated with High Pressure Processing and Trans-Cinnamaldehyde

2018 ◽  
Vol 83 (3) ◽  
pp. 740-749 ◽  
Author(s):  
Shiowshuh Sheen ◽  
Chi-Yun Huang ◽  
Rommel Ramos ◽  
Shih-Yung Chien ◽  
O. Joseph Scullen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
High Pressure Processing ◽  
Escherichia Coli O157 ◽  
E Coli

Application of High Pressure Processing To Kill Escherichia coli O157 in Ready-to-Eat Meats

2008 ◽  
Vol 71 (11) ◽  
pp. 2182-2189 ◽  
Author(s):  
ALEXANDER O. GILL ◽  
HOSAHALLI S. RAMASWAMY
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
Hold Time ◽  
Foodborne Pathogen ◽  
Immunomagnetic Separation ◽  
High Pressure Processing ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Reflected Light ◽  
Additional Reduction

Uncooked ready-to-eat (RTE) meats have previously been identified as vehicles for the transmission of the foodborne pathogen Escherichia coli O157. In this study, the potential for high pressure processing (HPP) to kill E. coli O157 in two RTE meats (Hungarian salami and All Beef salami) was investigated. The RTE meats were inoculated with a five-strain cocktail of E. coli O157, vacuum packed, and then pressure treated at 600 MPa with a hold time of 3 min. Samples were stored at 15°C for 28 days. HPP initially reduced E. coli numbers on both RTE meats by greater than 4 log CFU/g. However, with enrichment and immunomagnetic separation we were able to recover E. coli O157 from the samples. During storage, the numbers of E. coli O157 increased on the All Beef samples but remained static on the Hungarian salami, which had a restrictive pH and water activity. Increasing the hold time to 6 or 9 min did not result in additional reduction of E. coli O157. The sensory appeal of the two products was not significantly changed by HPP as determined by a sensory panel (n = 50). Analysis of the reflected light parameters of luminance, green-red, and blue-yellow revealed no significant changes. The results of these experiments indicate that HPP has potential as a lethal treatment for E. coli O157 on RTE meats with minimal changes in consumer appeal.

Use of Nonpathogenic Escherichia coli Surrogates as Predictors of the Survival of Nontyphoidal Salmonella, non-O157 Shiga Toxin–Producing Escherichia coli, and Escherichia coli O157 Populations after High Hydrostatic Pressure Processing

2018 ◽  
Vol 81 (7) ◽  
pp. 1068-1072 ◽  
Author(s):  
DALE R. WOERNER ◽  
IFIGENIA GEORNARAS ◽  
JENNIFER N. MARTIN ◽  
KEITH E. BELK ◽  
GARY R. ACUFF ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
Shiga Toxin ◽  
Pathogenic Bacteria ◽  
Ground Beef ◽  
High Pressure Processing ◽  
Escherichia Coli O157 ◽  
Specific Level ◽  
E Coli ◽  
Pathogen Populations

ABSTRACT Validated surrogates are a useful tool for studying the response of pathogens to food safety interventions, but better surrogates are needed for studies using high pressure processing. Ground beef (85% lean, 15% fat) was inoculated separately with mixed cultures of Escherichia coli O157, non-O157 Shiga toxin–producing E. coli, nontyphoidal Salmonella, and nonpathogenic E. coli surrogate bacteria. The inoculated ground beef was subjected to high hydrostatic pressures of 200, 400, and 600 MPa for 4, 6, and 8 min at each pressure. High pressure processing at 200 MPa reduced the inoculated populations of the pathogenic bacteria by 0.9 to 1.8 log CFU/g, 400 MPa reduced the inoculated populations by 2.5 to 3.6 log CFU/g, and 600 MPa reduced the inoculated populations by 4.5 to 5.6 log CFU/g. The nonpathogenic E. coli surrogates were more resistant to the effects of high pressure processing than were the inoculated pathogen populations. This finding suggests that the nonpathogenic E. coli surrogates could be used as process control indicators for high pressure processing of ground beef to predict a specific level of pathogen reduction. The surviving populations of the potential surrogate bacteria were proportional to the surviving populations of the pathogenic bacteria. The models allow for an estimation of the potential surviving populations of the pathogenic bacteria based on quantitative results of the populations of the surrogate bacteria.

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 < 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 < 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.

Reduction of Escherichia coli O157:H7 Counts on Whole Fresh Apples by Treatment with Sanitizers

2000 ◽  
Vol 63 (6) ◽  
pp. 703-708 ◽  
Author(s):  
MARCY A. WISNIEWSKY ◽  
BONITA A. GLATZ ◽  
MARK L. GLEASON ◽  
CHERYLL A. REITMEIER
Keyword(s):  
Escherichia Coli ◽  
Chlorine Dioxide ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Escherichia Coli O157 ◽  
Peroxyacetic Acid ◽  
Water Control ◽  
Buffer Solution ◽  
E Coli ◽  
Log Reduction

The objectives of this study were to determine if washing of whole apples with solutions of three different sanitizers (peroxyacetic acid, chlorine dioxide, or a chlorine-phosphate buffer solution) could reduce a contaminating nonpathogenic Escherichia coli O157:H7 population by 5 logs and at what sanitizer concentration and wash time such a reduction could be achieved. Sanitizers were tested at 1, 2, 4, 8, and 16 times the manufacturer's recommended concentration at wash times of 5, 10, and 15 min. Whole, sound Braeburn apples were inoculated with approximately 1 × 108 or 7 × 106 CFU per apple, stored for 24 h, then washed with sterile water (control) or with sanitizers for the prescribed time. Recovered bacteria were enumerated on trypticase soy agar. Washing with water alone reduced the recoverable population by almost 2 logs from the starting population; this can be attributed to physical removal of organisms from the apple surface. No sanitizer, when used at the recommended concentration, reduced the recovered E. coli population by 5 logs under the test conditions. The most effective sanitizer, peroxyacetic acid, achieved a 5-log reduction when used at 2.1 to 14 times its recommended concentration, depending on the length of the wash time. The chlorine-phosphate buffer solution reduced the population by 5 logs when used at 3 to 15 times its recommended concentration, depending on wash time. At no concentration or wash time tested did chlorine dioxide achieve the 5-log reduction.

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