Antibacterial Effect of Lactoferricin B on Escherichia coli O157:H7 in Ground Beef

1999 ◽  
Vol 62 (7) ◽  
pp. 747-750 ◽  
Author(s):  
KUMAR S. VENKITANARAYANAN ◽  
TONG ZHAO ◽  
MICHAEL P. DOYLE
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Effect ◽  
Ground Beef ◽  
Enterohemorrhagic Escherichia Coli ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Significant Difference ◽  
Sufficient Magnitude ◽  
Peptone Medium

The antibacterial activity of lactoferricin B on enterohemorrhagic Escherichia coli O157:H7 in 1% peptone medium and ground beef was studied at 4 and 10°C. In 1% peptone medium, 50 and 100 μg of lactoferricin B per ml reduced E. coli O157:H7 populations by approximately 0.7 and 2.0 log CFU/ml, respectively. Studies comparing the antibacterial effect of lactoferricin B on E. coli O157:H7 in 1% peptone at pH 5.5 and 7.2 did not reveal any significant difference (P > 0.5) at the two pH values. Lactoferricin B (100 μg/g) reduced E. coli O157:H7 population in ground beef by about 0.8 log CFU/g (P < 0.05). No significant difference (P > 0.5) was observed in the total plate count between treatment and control ground beef samples stored at 4 and 10°C. The antibacterial effect of lactoferricin B on E. coli O157:H7 observed in this study is not of sufficient magnitude to merit its use in ground beef for controlling the pathogen.

Survival of Escherichia coli O157:H7 in Ground-Beef Patties during Storage at 2, −2, 15 and then −2°C, and −20°C†

1999 ◽  
Vol 62 (11) ◽  
pp. 1243-1247 ◽  
Author(s):  
SUSAN E. ANSAY ◽  
KIM A. DARLING ◽  
CHARLES W. KASPAR
Keyword(s):  
Escherichia Coli ◽  
Frozen Storage ◽  
Ground Beef ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
Control Strain ◽  
Single Strain ◽  
E Coli ◽  
Beef Patties ◽  
Significant Difference

The survival of Escherichia coli O157:H7 and of a nonpathogenic control strain of E. coli was monitored in raw ground beef that was stored at 2°C for 4 weeks, −2°C for 4 weeks, 15°C for 4 h and then −2°C for 4 weeks, and −20°C. Irradiated ground beef was inoculated with one E. coli control strain or with a four-strain cocktail of E. coli O157:H7 (ca. 105 CFU/g), formed into patties (30 to 45 g), and stored at the appropriate temperature. The numbers of the E. coli control strain decreased by 1.4 log10 CFU/g, and pathogen numbers declined 1.9 log10 CFU/g when patties were stored for 4 weeks at 2°C. When patties were stored at −2°C for 4 weeks, the numbers of the E. coli control strain and the serotype O157:H7 strains decreased 2.8 and 1.5 log10 CFU/g, respectively. Patties stored at 15°C for 4 h prior to storage at −2°C for 4 weeks resulted in 1.6 and 2.7 log10–CFU/g reduction in the numbers of E. coli and E. coli O157:H7, respectively. Storage of retail ground beef at 15°C for 4 h (tempering) did not result in increased numbers of colony forming units per gram, as determined with violet red bile, MRS lactobacilli, and plate-count agars. Frozen storage (−20°C) of ground-beef patties that had been inoculated with a single strain of E. coli resulted in approximately a 1 to 2 log10–CFU/g reduction in the numbers of the control strain and individual serotype O157:H7 strains after 1 year. There was no significant difference between the survival of the control strain and the O157:H7 strains, nor was there a difference between O157:H7 strains. These data demonstrate that tempering of ground-beef patties prior to low-temperature storage accelerated the decline in the numbers of E. coli O157:H7.

Bioluminescence: A Rapid Indicator of Escherichia Coli O157:H7 in Selected Yogurt and Cheese Varieties

1997 ◽  
Vol 60 (8) ◽  
pp. 891-897 ◽  
Author(s):  
L. M. HUDSON ◽  
J. CHEN ◽  
A. R. HILL ◽  
M. W. GRIFFITHS
Keyword(s):  
Escherichia Coli ◽  
Enterohemorrhagic Escherichia Coli ◽  
Cottage Cheese ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
Potential Hazard ◽  
Growth And Survival ◽  
E Coli ◽  
Standard Plate Count ◽  
Standard Plate

Outbreaks of enterohemorrhagic Escherichia coli O157:H7 have been commonly associated with products derived from ground beef, but recently the organism has been implicated as the causative agent in outbreaks involving yogurt and cheese. This finding has raised concern about the potential for its growth and survival in fermented dairy products. A bioluminescent strain of E. coli O157:H7 was used to determine postprocessing survival in yogurt with live cultures at pH 4.17, 4.39, and 4.47 stored at 4 and 10°C. In addition, survival of E. coli O157:H7 was monitored during the manufacture of Cottage, Colby, Romano, and Feta cheeses. Results indicated survival for 8 and 5 days at 4 and 10°C respectively in yogurt at pH 4.17, 17 and 15 days at 4 and 10°C respectively in yogurt at pH 4.39, and 17days at both 4 and 10°C in yogurt at pH 4.47. E. coli O157:H7 did not survive cooking procedures at 56°C in Cottage cheese. However, the pathogen survived for 27, 30, and 27 days in Colby, Romano, and Feta cheeses respectively. A high correlation of r2 > 0.89 was obtained between counts of bioluminescenct colonies and standard plate count for all yogurt and cheese varieties, indicating that bioluminescence was a sensitive and rapid indicator of cellular viability for E. coli O157:H7. Survival of the pathogen, as indicated by this method, is possible in highly acidic environments even at refrigeration temperatures. This poses a potential hazard should postprocessing contamination occur.

Comparative Evaluation of a Phage Protein Ligand Assay with Real-Time PCR and a Reference Method for the Detection of Escherichia coli O157:H7 in Raw Ground Beef and Trimmings

2011 ◽  
Vol 74 (1) ◽  
pp. 6-12 ◽  
Author(s):  
F. SAVOYE ◽  
P. FENG ◽  
C. ROZAND ◽  
M. BOUVIER ◽  
A. GLEIZAL ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Real Time ◽  
Ground Beef ◽  
Reference Method ◽  
Enterohemorrhagic Escherichia Coli ◽  
Detection Methods ◽  
Escherichia Coli O157 ◽  
Rt Pcr ◽  
Raw Meat ◽  
E Coli

Enterohemorrhagic Escherichia coli O157:H7 is an important pathogen associated with infections caused by consumption of undercooked raw meat. Sensitive and rapid detection methods for E. coli O157:H7 are essential for the meat industry to ensure a safe meat supply. This study was conducted to compare the sensitivity of the VIDAS ultraperformance E. coli test (ECPT UP) with a noncommercial real-time (RT) PCR method and the U.S. Department of Agriculture, Food Safety and Inspection Service (USDA-FSIS) reference method for detecting E. coli O157:H7 in raw ground beef. Optimal enrichment times and the efficacy of testing different types of raw meat, either as individual samples (25 g) or as composites (375 g), were examined. For 25-g samples of each type of raw ground beef tested, 6 h of enrichment was sufficient for both the VIDAS ECPT UP and RT-PCR methods, but for 375-g samples, 24 h of enrichment was required. Both the VIDAS ECPT UP and RT-PCR methods produced results similar to those obtained with the USDA-FSIS reference method after 18 to 24 h of enrichment. The primer specificity of the RT-PCR assay and the highly specific phage ligand used in the VIDAS ECPT UP for target recognition enabled the detection of low levels of E. coli O157:H7 in 25 g of various types of raw ground beef. The tests also allowed the detection of E. coli O157:H7 in composite raw ground beef and trimmings in samples of up to 375 g.

Fate of Enterohemorrhagic Escherichia coli O157: H7 in Commercial Mayonnaise

1994 ◽  
Vol 57 (9) ◽  
pp. 780-783 ◽  
Author(s):  
TONG ZHAO ◽  
MICHAEL P. DOYLE
Keyword(s):  
Escherichia Coli ◽  
Enterohemorrhagic Escherichia Coli ◽  
Health Concern ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Initial Ph ◽  
Contaminated Food ◽  
Aerobic Plate Count ◽  
Mold And Yeast

The fate of enterohemorrhagic Escherichia coli O157:H7 was determined in three different lots of commercial mayonnaise, including four different samples from a lot implicated in an outbreak of E. coli O157:H7 infection. The initial pH of the products ranged from 3.6 to 3.9. Products were inoculated with 6.5 × 103 E. coli O157:H7/g and incubated at 5 or 20°C. Escherichia coli O157:H7 did not grow at either temperature but survived for 34 to 55 days at 5°C and for 8 to 21 days at 20°C, depending on the lot. Survival was greatest in real mayonnaise purchased at retail among six mayonnaise samples which included a reduced calorie mayonnaise. Escherichia coli O157:H7 populations decreased between 2- and 100-fold by 3 weeks at 5°C, and between 10- and 1,000-fold by 7 days at 20°C. There was little or no change in pH (<0.1 unit), aerobic plate count, mold and yeast count or Lactobacillus count (< 1 log10 CFU/g) for the duration of the study. Commercial mayonnaise manufactured under good manufacturing practices is not a public health concern. Abusive handling of mayonnaise resulting in cross-contamination with E. coli O157:H7-contaminated food or contamination by an infected foodhandler is the principal basis for concern.

Growth Rates of Salmonella and Escherichia coli O157:H7 in Irradiated Beef†

2001 ◽  
Vol 64 (11) ◽  
pp. 1828-1831 ◽  
Author(s):  
J. S. DICKSON ◽  
D. G. OLSON
Keyword(s):  
Escherichia Coli ◽  
Growth Parameters ◽  
Ground Beef ◽  
Lag Phase ◽  
Escherichia Coli O157 ◽  
Phase Duration ◽  
E Coli ◽  
Generation Times ◽  
Significant Difference ◽  
Spoilage Microflora

Ground beef was irradiated to 0, 2, or 4 kGy and then inoculated with a mixed culture of four serotypes of salmonellae or five strains of Escherichia coli O157:H7. The ground beef was stored at either 15 or 25°C, and the growth of the inoculated bacteria was monitored over time. Growth parameters were determined for both the salmonellae and the E. coli O157:H7 using the Gompertz equation. There was no significant difference in lag phase duration or generation time, irrespective of the dose to which the ground beef had previously been exposed. Furthermore, the lag phase durations and generation times determined in this study did not differ significantly from previously published values. This suggests that, although irradiation eliminates a significant portion of the spoilage microflora in ground beef, the absence of this microflora provides no competitive advantage to the growth of salmonellae or E. coli O157:H7 in ground beef.

Incidence of Enterohemorrhagic Escherichia coli, Escherichia coli O157, Salmonella, and Listeria monocytogenes in Retail Fresh Ground Beef, Sprouts, and Mushrooms

2006 ◽  
Vol 69 (2) ◽  
pp. 441-443 ◽  
Author(s):  
M. SAMADPOUR ◽  
M. W. BARBOUR ◽  
T. NGUYEN ◽  
T.-M. CAO ◽  
F. BUCK ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Ground Beef ◽  
Food Samples ◽  
Enterohemorrhagic Escherichia Coli ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Pcr Assays ◽  
Retail Food

The objective of this study was to determine the prevalence of enterohemorrhagic Escherichia coli (EHEC), E. coli O157, Salmonella, and Listeria monocytogenes in retail food samples from Seattle, Wash. A total of 2,050 samples of ground beef (1,750 samples), mushrooms (100 samples), and sprouts (200 samples) were collected over a 12-month period and analyzed for the presence of these pathogens. PCR assays, followed by culture confirmation were used to determine the presence or absence of each organism. Of the 1,750 ground beef samples analyzed, 61 (3.5%) were positive for EHEC, and 20 (1.1%) of these were positive for E. coli O157. Salmonella was present in 67 (3.8%) of the 1,750 ground beef samples. Of 512 ground beef samples analyzed, 18 (3.5%) were positive for L. monocytogenes. EHEC was found in 12 (6.0%) of the 200 sprout samples, and 3 (1.5%) of these yielded E. coli O157. Of the 200 total sprout samples, 14 (7.0%) were positive for Salmonella and none were positive for L. monocytogenes. Among the 100 mushroom samples, 4 (4.0%) were positive for EHEC but none of these 4 samples were positive for E. coli O157. Salmonella was detected in 5 (5.0%) of the mushroom samples, and L. monocytogenes was found in 1 (1.0%) of the samples.

scholarly journals Improvement of Immunomagnetic Separation for Escherichia coli O157:H7 Detection by the PickPen Magnetic Particle Separation Device†

2006 ◽  
Vol 69 (12) ◽  
pp. 2870-2874 ◽  
Author(s):  
XIANGWU NOU ◽  
TERRANCE M. ARTHUR ◽  
JOSEPH M. BOSILEVAC ◽  
DAYNA M. BRICHTA-HARHAY ◽  
MICHAEL N. GUERINI ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pathogen Detection ◽  
Magnetic Particles ◽  
Magnetic Particle ◽  
Ground Beef ◽  
Immunomagnetic Separation ◽  
Escherichia Coli O157 ◽  
High Background ◽  
E Coli ◽  
Significant Difference

Conventional immunomagnetic separation (IMS) procedures, which use an external magnetic source to capture magnetic particles against the side of a test tube, are labor-intensive and can have poor sensitivity for the target organism because of high background microflora that is not effectively washed away during the IMS process. This report compares the conventional IMS procedure to a new IMS procedure with an intrasolution magnetic particle transfer device, the PickPen. The IMS target for the majority of these studies is Escherichia coli O157:H7 in various types of samples, including cattle feces, hides, carcasses, and ground beef. Comparison of the two IMS methods showed a significant difference (P < 0.05) in the efficiency of detecting E. coli O157:H7 from cattle carcass surface, cattle hide, and cattle fecal samples. No significant improvement (P > 0.05) in E. coli O157:H7 detection was observed when the PickPen IMS procedure was used to isolate this pathogen from ground beef samples. Use of the PickPen IMS greatly increases the throughput of the IMS procedure and may be more compatible with various emerging technologies for pathogen detection. In addition, the efficacy of sequential IMS for multiple pathogens is reported herein.

Attachment of Escherichia coli O157:H7 in Ground Beef to Meat Grinders and Survival after Sanitation with Chlorine and Peroxyacetic Acid

1998 ◽  
Vol 61 (7) ◽  
pp. 817-822 ◽  
Author(s):  
BRIDGET L. FARRELL ◽  
AMY B. RONNER ◽  
AMY C. LEE WONG
Keyword(s):  
Escherichia Coli ◽  
Limit Of Detection ◽  
Ground Beef ◽  
Plate Count ◽  
Residual Soil ◽  
Escherichia Coli O157 ◽  
Peroxyacetic Acid ◽  
E Coli ◽  
Bioluminescence Assay ◽  
Atp Bioluminescence Assay

The potential for transfer of Escherichia coli O157:H7 from contaminated ground beef to grinding equipment and the inactivation of attached cells during cleaning and sanitizing was examined. Chub-packed ground beef with lean:fat ratios of 75:25, 80:20, or 90:10 was inoculated with 6 log CFU/g or 2 log CFU/g E. coli O157:H7 strain FRIK 910. Samples were consecutively ground in a Hobart meat grinder with stainless Steel (SS) chips (1 cm2) glued to the auger housing. Chips were harvested after grinding, detergent washing with or without manual scrubbing and rinsing, sanitizing in a chlorine or peroxyacetic acid sanitizer, and overnight storage. Survival of E. coli O157:H7 was evaluated both by plate count and enrichment in trypticase soy broth. Approximately 3 to 4 log CFU/cm2 were attached to the SS after grinding with all three fat contents. After washing and sanitizing in a chlorine or peroxyacetic acid sanitizer, viable bacteria were infrequently recovered by plate count. Enrichment of chips resulted in a higher survival rate with both sanitizing treatments, indicating that cell numbers below the limit of detection (5 CFU/cm2) or potentially injured organisms remained on the surface. Manual scrubbing during the washing step reduced the recovery rate. The scrubbing step also increased the number of passing scores assigned using an ATP bioluminescence assay of total residual soil on the chips sanitized in chlorine. The overall results indicate that plate counts alone may not be a reliable indicator of sanitation efficacy and may be validated by enrichment assay.

Comparison of β-Glucuronidase and Indole-Based Direct Plating Methods for Enumerating Escherichia coli in Artificially Inoculated Ground Meats

1990 ◽  
Vol 53 (11) ◽  
pp. 933-935 ◽  
Author(s):  
ELON W. FRAMPTON ◽  
LAWRENCE RESTAINO ◽  
NANCY BLASZKO
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Plate Count ◽  
Most Probable Number ◽  
Probable Number ◽  
E Coli ◽  
Glucuronidase Activity ◽  
Plate Count Agar ◽  
Significant Difference ◽  
Indole Production

Peptone tergitol glucuronide (PTG) agar containing 4-methylumbelliferyl-β-D glucuronide (MUG) (for β-glucuronidase activity), the Holbrook, Anderson, Baird-Parker (HABP) method (for detecting indole production), and the standard 3-tube most probable number (MPN) method were compared with plate count agar (PCA) for enumerating three strains of unstressed Escherichia coli artificially inoculated into ground beef and chicken at 1–6 × 106 cells/g. No significant difference (P>0.05) was determined between PTG agar and PCA in the recovery of E. coli. The MPN method enumerated a significantly greater (P<0.05) number of E. coli cells than PCA. Compared with PCA, the HABP method recovered a significantly lower (P<0.05) number of E. coli cells from chicken, whereas no significant difference (P>0.05) was obtained with ground beef. When combining all data from chicken and beef, the recovery of E. coli cells by the HABP method was also significantly lower (P<0.05). Overall, based on the enumeration of E. coli on PCA, the HABP method, PTG agar, and MPN method recovered 57, 102, and 144%, respectively.

Incidence of Escherichia coli O157:H7 in Frozen Beef Patties Produced over an 8-Hour Shift†

2002 ◽  
Vol 65 (9) ◽  
pp. 1363-1370 ◽  
Author(s):  
W. PAYTON PRUETT ◽  
TIMOTHY BIELA ◽  
CHARLES P. LATTUADA ◽  
PETER M. MROZINSKI ◽  
W. MARK BARBOUR ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Food Service ◽  
Ground Beef ◽  
Raw Material ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Beef Patties ◽  
Entry Points ◽  
Positive Results

A ground beef patty processor detected Escherichia coli O157:H7 in five production lots during routine testing with polymerase chain reaction (PCR) technology. This finding stimulated research to determine the incidence and potential entry points of the pathogen during processing. One of these lots (53,960 kg) was divided into 71 pallets (760 kg each) of food service ground beef patties. Ten cartons (19 kg each) were removed from each pallet, for a total of 710 cartons. Four patties were taken from each carton and subdivided to provide comparable samples for E. coli O157:H7 analyses by three different laboratories. Two laboratories employed different immunoassay tests, and one used PCR to screen samples. One sample set was analyzed for aerobic plate, coliform, and E. coli Biotype I counts to determine if any relationship existed between these microbial groups and the incidence of E. coli O157:H7. For 73 samples, presumptive positive results for E. coli O157:H7 were obtained by one or more methods. For 48 of these 73 samples, positive results for the pathogen were culture confirmed. The largest number (29) of culture-confirmed positive E. coli O157:H7 results were detected by PCR. Most positive results were obtained during a short segment of processing. All culture-confirmed E. coli O157:H7 strains were further characterized by two genetic subtyping techniques, resulting in two to four different patterns, depending on the subtyping procedure employed. For any sample tested, the aerobic plate count was <3.0 log CFU/g, and coliform and E. coli Biotype I counts were ≤1.00 log CFU/g. The results of this study suggest that most positive samples were associated with a contaminated batch of raw material introduced just before the 1725- to 1844-h processing segment. These results also indicate that more aggressive sampling plans and genetic screening technologies such as PCR may be used to better detect low levels of E. coli O157:H7 in ground beef products.

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