scholarly journals Evaluation of post-fermentation heating times and temperatures for controlling Shiga toxin-producing Escherichia coli cells in a non-dried, pepperoni-type sausage

2018 ◽  
Vol 7 (2) ◽  
Author(s):  
Laura E. Shane ◽  
Anna C.S. Porto-Fett ◽  
Bradley A. Shoyer ◽  
Randall K. Phebus ◽  
Harshavardhan Thippareddi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Heating Temperature ◽  
Starter Culture ◽  
Pediococcus Acidilactici ◽  
Ground Meat ◽  
Escherichia Coli Cells

Coarse ground meat was mixed with non-meat ingredients and starter culture (Pediococcus acidilactici) and then inoculated with an 8-strain cocktail of Shiga toxinproducing Escherichia coli (ca. 7.0 log CFU/g). Batter was fine ground, stuffed into fibrous casings, and fermented at 35.6°C and ca. 85% RH to a final target pH of ca. pH 4.6 or ca. pH 5.0. After fermentation, the pepperoni- like sausage were heated to target internal temperatures of 37.8°, 43.3°, 48.9°, and 54.4°C and held for 0.5 to 12.5 h. Regardless of the heating temperature, the endpoint pH in products fermented to a target pH of pH 4.6 and pH 5.0 was pH 4.56±0.13 (range of pH 4.20 to pH 4.86) and pH 4.96±0.12 (range of pH 4.70 to pH 5.21), respectively. Fermentation alone delivered ca. a 0.3- to 1.2-log CFU/g reduction in pathogen numbers. Fermentation to ca. pH 4.6 or ca. pH 5.0 followed by post-fermentation heating to 37.8° to 54.4°C and holding for 0.5 to 12.5 h generated total reductions of ca. 2.0 to 6.7 log CFU/g.

scholarly journals Influence of Culture Conditions and Medium Composition on the Production of Cellulose by Shiga Toxin-Producing Escherichia coli Cells

2009 ◽  
Vol 75 (13) ◽  
pp. 4630-4632 ◽  
Author(s):  
Byong Kwon Yoo ◽  
Jinru Chen
Keyword(s):  
Escherichia Coli ◽  
Water Activity ◽  
Shiga Toxin ◽  
Incubation Temperature ◽  
Culture Conditions ◽  
Luria Bertani ◽  
Medium Composition ◽  
Cellulose Production ◽  
Escherichia Coli Cells

ABSTRACT Culture conditions favoring cellulose production by Shiga toxin-producing Escherichia coli included a 28°C incubation temperature, an aerobic atmosphere, and the presence of 2% ethanol in Luria-Bertani no-salt agar with pH 6.0 and a water activity of 0.99. These findings will assist in formulating microbiological media useful for cellulose and biofilm research.

Fate of Shiga Toxin–Producing O157:H7 and Non-O157:H7 Escherichia coli Cells within Blade-Tenderized Beef Steaks after Cooking on a Commercial Open-Flame Gas Grill†

2012 ◽  
Vol 75 (1) ◽  
pp. 62-70 ◽  
Author(s):  
JOHN B. LUCHANSKY ◽  
ANNA C. S. PORTO-FETT ◽  
BRADLEY A. SHOYER ◽  
JEFFREY E. CALL ◽  
WAYNE SCHLOSSER ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Phase I ◽  
Phase Ii ◽  
Shiga Toxin ◽  
Escherichia Coli O157 ◽  
Open Flame ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
Beef Steaks ◽  
Uneven Heating

We compared the fate of cells of both Shiga toxin–producing Escherichia coli O157:H7 (ECOH) and Shiga toxin–producing non-O157:H7 E. coli (STEC) in blade-tenderized steaks after tenderization and cooking on a gas grill. In phase I, beef subprimal cuts were inoculated on the lean side with about 5.5 log CFU/g of a five-strain mixture of ECOH or STEC and then passed once through a mechanical blade tenderizer with the lean side facing up. In each of two trials, 10 core samples were removed from each of two tenderized subprimals and cut into six consecutive segments starting from the inoculated side. Ten total cores also were obtained from two nontenderized (control) subprimals, but only segment 1 (the topmost segment) was sampled. The levels of ECOH and STEC recovered from segment 1 were about 6.0 and 5.3 log CFU/g, respectively, for the control subprimals and about 5.7 and 5.0 log CFU/g, respectively, for the tenderized subprimals. However, both ECOH and STEC behaved similarly in terms of translocation, and cells of both pathogen cocktails were recovered from all six segments of the cores obtained from tenderized subprimals, albeit at lower levels in segments 2 to 6 than those found in segment 1. In phase II, steaks (2.54 and 3.81 cm thick) cut from tenderized subprimals were subsequently cooked (three steaks per treatment) on a commercial open-flame gas grill to internal temperatures of 48.9, 54.4, 60.0, 65.6, and 71.1°C. Regardless of temperature or thickness, we observed 2.0- to 4.1-log and 1.5- to 4.5-log reductions in ECOH and STEC levels, respectively. Both ECOH and STEC behaved similarly in response to heat, in that cooking eliminated significant numbers of both pathogen types; however, some survivors were recovered due, presumably, to uneven heating of the blade-tenderized steaks.

scholarly journals Survival of Shiga Toxin-Producing Escherichia coli (STEC) Serogroups During Production and Storage of Yogurt

2021 ◽  
Vol 72 (1) ◽  
pp. 2689
Author(s):  
G CELIK ◽  
A DIKICI ◽  
A KOLUMAN
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Starter Culture ◽  
Escherichia Coli O157 ◽  
Potential Health ◽  
Potential Health Risk ◽  
E Coli ◽  
Lactic Acid Content ◽  
And Storage ◽  
Lactobacillus Spp

In this study, the survival of Escherichia coli O157:H7 and non-O157 STEC serogroups of O26, O111, O103, and O145 were investigated during production and storage of yogurt. For this purpose, pathogens were individually inoculated into milk after pasteurization along with the starter culture (approximately 7.00±1.00 log10 cfu/g). After incubation at 44oC (about 180 min), yogurt samples were capped and stored at 4oC for 20 days. Pathogens were enumerated at 0, 5, 10, 15, and 20th days of storage. Lactic acid content (%) and pH of the samples were also screened. Moreover, mesophilic Lactococcus spp. and mesophilic Lactobacillus spp. were enumerated during production of yogurt.After incubation, the number of E. coli O157, O26, O103, O145, O111were 6.76±0.45, 6.64±0.53, 7.12±0.43, 6.00±1.39, 5.89±1.37 log10 cfu/g, respectively. A significant decrease was determined in all groups during the storage of yogurt samples at 4oC (p<0.05). It was detected on the 20th day of storage that the number of E. coli O157:H7 and non-O157 STEC serogroups of O103 and O145 were under the detection limit. However, STEC O26 and O111 were viable around 1.51±0.98 and 1.18±0.62 log10 cfu/g respectively. Results of the study showed that Escherichia coli O157:H7 and non-O157 STEC serogroups might pose a potential health risk during production and storage of yogurt.

Fate of Shiga Toxin–Producing O157:H7 and Non-O157:H7 Escherichia coli Cells within Refrigerated, Frozen, or Frozen Then Thawed Ground Beef Patties Cooked on a Commercial Open-Flame Gas or a Clamshell Electric Grill†

2013 ◽  
Vol 76 (9) ◽  
pp. 1500-1512 ◽  
Author(s):  
JOHN B. LUCHANSKY ◽  
ANNA C. S. PORTO-FETT ◽  
BRADLEY A. SHOYER ◽  
JOHN PHILLIPS ◽  
VIVIAN CHEN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Initial Level ◽  
Ground Beef ◽  
High Fat ◽  
E Coli ◽  
Final Level ◽  
Beef Patties ◽  
Escherichia Coli Cells ◽  
Fat Level

Both high-fat and low-fat ground beef (percent lean:fat = ca. 70:30 and 93:7, respectively) were inoculated with a 6-strain cocktail of non-O157:H7 Shiga toxin–producing Escherichia coli (STEC) or a five-strain cocktail of E. coli O157:H7 (ca. 7.0 log CFU/g). Patties were pressed (ca. 2.54 cm thick, ca. 300 g each) and then refrigerated (4°C, 18 to 24 h), or frozen (−18°C, 3 weeks), or frozen (−18°C, 3 weeks) and then thawed (4°C for 18 h or 21°C for 10 h) before being cooked on commercial gas or electric grills to internal temperatures of 60 to 76.6°C. For E. coli O157:H7, regardless of grill type or fat level, cooking refrigerated patties to 71.1 or 76.6°C decreased E. coli O157:H7 numbers from an initial level of ca. 7.0 log CFU/g to a final level of ≤1.0 log CFU/g, whereas decreases to ca. 1.1 to 3.1 log CFU/g were observed when refrigerated patties were cooked to 60.0 or 65.5°C. For patties that were frozen or freeze-thawed and cooked to 71.1 or 76.6°C, E. coli O157:H7 numbers decreased to ca. 1.7 or ≤0.7 log CFU/g. Likewise, pathogen numbers decreased to ca. 0.7 to 3.7 log CFU/g in patties that were frozen or freeze-thawed and cooked to 60.0 or 65.5°C. For STEC, regardless of grill type or fat level, cooking refrigerated patties to 71.1 or 76.6°C decreased pathogen numbers from ca. 7.0 to ≤0.7 log CFU/g, whereas decreases to ca. 0.7 to 3.6 log CFU/g were observed when refrigerated patties were cooked to 60.0 or 65.5°C. For patties that were frozen or freeze-thawed and cooked to 71.1 or 76.6°C, STEC numbers decreased to a final level of ca. 1.5 to ≤0.7 log CFU/g. Likewise, pathogen numbers decreased from ca. 7.0 to ca. 0.8 to 4.3 log CFU/g in patties that were frozen or freeze-thawed and cooked to 60.0 or 65.5°C. Thus, cooking ground beef patties that were refrigerated, frozen, or freeze-thawed to internal temperatures of 71.1 and 76.6°C was effective for eliminating ca. 5.1 to 7.0 log CFU of E. coli O157:H7 and STEC per g.

scholarly journals Sensitivity of wild-type and rifampicin-resistant O157 and non-O157 Shiga toxin-producing Escherichia coli to elevated hydrostatic pressure and lactic acid in ground meat and meat homogenate

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246735
Author(s):  
Abimbola Allison ◽  
Aliyar Cyrus Fouladkhah
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Hydrostatic Pressure ◽  
Shiga Toxin ◽  
Meat Products ◽  
The United States ◽  
Health Concern ◽  
Ground Meat ◽  
Wild Type ◽  
Elevated Hydrostatic Pressure

Various serogroups of Shiga toxin-producing Escherichia coli have been epidemiologically associated with foodborne disease episodes in the United States and around the globe, with E. coli O157: H7 as the dominant serogroup of public health concern. Serogroups other than O157 are currently associated with about 60% of Shiga toxin-producing E. coli related foodborne illness episodes. Current study evaluated sensitivity of the O157 and epidemiologically important non-O157 serogroups of the pathogen to elevated hydrostatic pressure and 1% lactic acid. Pressure intensity of 250 to 650 MPa were applied for 0 to 7 min for inactivation of strain mixtures of wild-type and rifampicin-resistant E. coli O157, as well as O26, O45, O103, O111, O121, and O145 serogroups and ATCC® 43895™ strain in ground meat and 10% meat homogenate. E. coli O157 were reduced (p < 0.05) from 6.86 ± 0.2 to 4.56 ± 0.1 log CFU/g when exposed to pressure of 650 MPa for 7 min. Corresponding reductions (p < 0.05) for non-O157 E. coli were from 6.98 ± 0.3 to 4.72 ± 0.1. The D-values at 650 MPa were 3.71 and 3.47 min for O157 and non-O157 serogroups, respectively. Presence of 1% lactic acid to a great extent augmented (p < 0.05) decontamination efficacy of the treatment in meat homogenate resulting in up to 5.6 and 6.0 log CFU/mL reductions for O157 and non-O157 serogroups, respectively. Among the tested serogroups, the wild-type and rifampicin-resistant phenotypes exhibited (p ≥ 0.05) comparable pressure sensitivity. Thus, these two phenotypes could be used interchangeably in validation studies. Our results also illustrate that, application of elevated hydrostatic pressure could be utilized for assuring safety of ground and non-intact meat products against various serogroups of Shiga toxin-producing E. coli. Addition of 1% lactic acid additionally provided industrially appreciable augmentation in efficacy of the pressure-based treatments.

Thermal Inactivation of Escherichia coli O157:H7 and Non-O157 Shiga Toxin–Producing Escherichia coli Cells in Mechanically Tenderized Veal†

2014 ◽  
Vol 77 (7) ◽  
pp. 1201-1206 ◽  
Author(s):  
JOHN B. LUCHANSKY ◽  
ANNA C. S. PORTO-FETT ◽  
BRADLEY A. SHOYER ◽  
HARSHAVARDHAN THIPPAREDDI ◽  
JESUS R. AMAYA ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Thermal Inactivation ◽  
Escherichia Coli O157 ◽  
Internal Temperature ◽  
E Coli ◽  
Log Reduction ◽  
Cooking Oil ◽  
Escherichia Coli Cells ◽  
Cooking Times

Preflattened veal cutlets (ca. 71.5 g, ca. 0.32 cm thick) were surface inoculated with ca. 6.8 log CFU/g of a multistrain cocktail of Escherichia coli O157:H7 (ECOH) or a cocktail made of single strains of serogroups O26, O45, O103, O104, O111, O121, and O145 of Shiga toxin–producing E. coli (STEC) cells and then were mechanically tenderized by passing once through a “Sir Steak” tenderizer. For each cooking time, in each of at least three trials, three inoculated and tenderized cutlets, with and without breading, were individually cooked in 15 or 30 ml of canola oil for 0.0, 0.75, 1.0, 1.25, 1.5, 1.75, or 2.25 min per side on an electric skillet set at 191.5°C. The temperatures of the meat and of the skillet were monitored and recorded using a type J thermocouple. Regardless of the breading or volume of oil used to cook the meat, the longer the cooking times, the higher was the internal temperature of the meat, along with a greater reduction of both ECOH and STEC. The average final internal temperature of the meat at the approximate geometric center ranged from 56.8 to 93.1°C. Microbial reductions of ca. 2.0 to 6.7 log CFU/g and ca. 2.6 to 6.2 log CFU/g were achieved for ECOH and STEC, respectively. Our data also revealed no differences in thermal inactivation of ECOH relative to the volume of oil used to cook nonbreaded cutlets. However, when cooking breaded cutlets, the use of more (30 ml) compared with less (15 ml) cooking oil resulted in greater reductions in pathogen numbers. To deliver about a 5.0-log reduction of ECOH and STEC, and to achieve the recommended internal temperature of 71.1°C, it was necessary to cook mechanically tenderized veal cutlets for at least 1.5 min per side on a preheated electric skillet set at 191.5°C and containing 15 ml of cooking oil. These data also established that cooking times and temperatures effective for inactivating serotype O157:H7 strains of E. coli in tenderized veal are equally effective against the additional six non-O157 Shiga toxin–producing strains investigated herein.

Stimulation of Starter Culture for Further Reduction of Foodborne Pathogens during Salami Fermentation

2000 ◽  
Vol 63 (11) ◽  
pp. 1492-1495 ◽  
Author(s):  
DONG-HYUN KANG ◽  
DANIEL Y. C. FUNG
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Starter Culture ◽  
Escherichia Coli O157 ◽  
Pediococcus Acidilactici ◽  
Log10 Reduction ◽  
E Coli ◽  
Manganese Ion ◽  
And Staphylococcus Aureus ◽  
Stimulation Of

This study was conducted to determine if stimulated meat starter culture (MSC; Pediococcus acidilactici) would further control Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus during salami fermentation. Manganese ion (0.005% of MnSO4) was used as a stimulator for the growth and acid production of MSC. After 24-h salami fermentation, nonstimulated MSC and stimulated MSC reduced E. coli O157:H7 levels by 1.3 and 2.3 log10 units, respectively. Nonstimulated MSC reduced L. monocytogenes levels by 1.2 log10 units, whereas the stimulated MSC achieved a 2.2-log10 reduction after 24-h fermentation. In the case of S. aureus, nonstimulated MSC and stimulated MSC reduced S. aureus levels by 1.3 and 2.3 log10 units after 24-h fermentation, respectively. Stimulated MSC by MnSO4 reduced those foodborne pathogens more effectively compared with nonstimulated MSC (P &lt; 0.05).

scholarly journals Inactivation of Shiga Toxin-Producing Escherichia coli in Refrigerated and Frozen Meatballs Using High Pressure Processing

2020 ◽  
Vol 8 (3) ◽  
pp. 360
Author(s):  
Anna C. S. Porto-Fett ◽  
Armitra Jackson-Davis ◽  
Lamin S. Kassama ◽  
Marciauna Daniel ◽  
Michelle Oliver ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
Shiga Toxin ◽  
Ground Beef ◽  
High Pressure Processing ◽  
Ground Meat ◽  
Pathogen Reduction ◽  
G Prior

High pressure processing (HPP) was evaluated to inactivate Shiga toxin-producing Escherichia coli (STEC) in raw meatballs. Ground meat (>90% lean) was inoculated (ca. 7.0 log CFU/g) with a rifampicin-resistant cocktail of eight STEC strains (O26:H11, O45:H2, O103:H2, O104:H4, O111:H-, O121:H19, O145:NM, and O157:H7). Inoculated ground beef, ground veal, or a mixture of ground beef, pork, and veal were separately mixed with liquid whole eggs and seasonings, shaped by hand into meatballs (40 g each), and stored at −20 or at 4 °C for at least 18 h. Samples were then exposed to 400 or 600 MPa for 0 to 18 min. There were no differences (p > 0.05) in pathogen reduction related to the species of meat used or for meatballs that were refrigerated (0.9 to 2.9 log CFU/g) compared to otherwise similar meatballs that were stored frozen (1.0 to 3.0 log CFU/g) prior to HPP treatment. However, less time was needed to achieve a ≥ 2.0 log CFU/g reduction at 600 MPa (1 to 3 min) compared to 400 MPa (at least 9 min). This work provides new and practically useful information on the use of HPP to inactivate STEC in raw meatballs.

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