Prevalence of Escherichia coli O157:H7 and Indicator Organisms on the Surface of Intact Subprimal Beef Cuts Prior to Further Processing

2006 ◽  
Vol 69 (7) ◽  
pp. 1514-1517 ◽  
Author(s):  
JAMES E. KENNEDY ◽  
SALLY K. WILLIAMS ◽  
TED BROWN ◽  
PHIL MINERICH
Keyword(s):  
Escherichia Coli ◽  
Total Coliform ◽  
Escherichia Coli O157 ◽  
Indicator Organisms ◽  
Seasonal Differences ◽  
Total Coliforms ◽  
E Coli ◽  
Plate Counts ◽  
Collection Period

The objective of this study was to determine the prevalence of Escherichia coli O157:H7, other E. coli strains, total coliforms, and aerobic organisms on the surface of subprimal beef cuts prior to enhancement. Subprimal cuts were sampled during winter (January and February 2004) and summer (August through October 2004). During each collection period, six representative subprimal cuts (chuck tenders, 0.64-cm trimmed strips, bottom round flat, rough-trimmed brisket, cap-on top rounds, and cap-off insides) were sampled. A total of 600 samples in winter (100 samples per cut) and 599 samples in summer (100 chuck tenders, 100 0.64-cm trimmed strips, 100 bottom round flats, 100 cap-off insides, 97 rough-trimmed briskets, and 102 cap-on top rounds) were collected from five plants in the Midwest, southern Midwest, northern Midwest, and Southeast and swabbed using the sponge swab method. All sponges were analyzed for E. coli O157:H7. In addition, 400 subprimal cuts from four plants were analyzed for aerobic plate counts, total coliforms, and other E. coli strains during each collection period. E. coli O157:H7 was not detected on any of the 1,199 subprimal samples; thus, incidence of E. coli O157:H7 was <0.083%. Seasonal differences between aerobic plate counts and total coliform counts for each of the same cuts were 1.0 log CFU per cut or less. E. coli strains were not detected in 82, 52, 69, and 82% of the chuck tenders, 0.64-cm trimmed strips, bottom round flats, and cap-off insides, respectively.

scholarly journals Escherichia coli O157 Prevalence and Enumeration of Aerobic Bacteria, Enterobacteriaceae, and Escherichia coli O157 at Various Steps in Commercial Beef Processing Plants†

2004 ◽  
Vol 67 (4) ◽  
pp. 658-665 ◽  
Author(s):  
TERRANCE M. ARTHUR ◽  
JOSEPH M. BOSILEVAC ◽  
XIANGWU NOU ◽  
STEVEN D. SHACKELFORD ◽  
TOMMY L. WHEELER ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Aerobic Bacteria ◽  
Escherichia Coli O157 ◽  
Indicator Organisms ◽  
E Coli ◽  
Beef Processing ◽  
Processing Plants ◽  
Plate Counts ◽  
On Line ◽  
Antimicrobial Interventions

The effectiveness of current antimicrobial interventions used in reducing the prevalence or load of Escherichia coli O157 and indicator organisms on cattle hides and carcasses at two commercial beef processing plants was evaluated. Sponge sampling of beef cattle was performed at five locations from the initial entry of the animals to the slaughter floor to the exit of carcasses from the “hotbox” cooler. For each sample, E. coli O157 prevalence was determined and total aerobic bacteria, Enterobacteriaceae, and E. coli O157 were enumerated. E. coli O157 was found on 76% of animal hides coming into the plants, but no carcasses leaving the cooler were identified as contaminated with E. coli O157. A positive relationship was seen between the incidence of E. coli O157 in hide samples and that in preevisceration samples. Aerobic plate counts and Enterobacteriaceae counts averaged 7.8 and 6.2 log CFU/100 cm2, respectively, on hides, and 1.4 and 0.4 log CFU/100 cm2, respectively, on chilled carcasses. Aerobic plate counts and Enterobacteriaceae counts on preevisceration carcasses were significantly related to the respective levels on the corresponding hides; the carcasses of animals whose hides carried higher numbers of bacteria were more likely to carry higher numbers of bacteria. Implementation of the sampling protocol described here would allow processors to evaluate the efficacy of on-line antimicrobial interventions and allow industrywide benchmarking of hygienic practices.

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 Simulated Dry and Wet Chilling and Aging of Beef Fat and Lean Tissues on the Reduction of Escherichia coli O157:H7 and Salmonella

2011 ◽  
Vol 74 (2) ◽  
pp. 289-293 ◽  
Author(s):  
A. W. TITTOR ◽  
M. G. TITTOR ◽  
M. M. BRASHEARS ◽  
J. C. BROOKS ◽  
A. J. GARMYN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Control Point ◽  
Tissue Type ◽  
Escherichia Coli O157 ◽  
Air Velocity ◽  
E Coli ◽  
Critical Control Point ◽  
Initial Reduction ◽  
Plate Counts ◽  
Antimicrobial Interventions

The efficacy of dry and wet chilling and aging of beef as methods for the reduction of Escherichia coli O157:H7 and Salmonella on lean and fat tissues was studied. Samples were obtained from a harvest facility prior to antimicrobial interventions and were inoculated with a cocktail mixture of E. coli O157:H7 or Salmonella to achieve a target inoculation of 6 log CFU/cm2. Wet chilled and aged samples were then suspended, sprayed (10°C) continuously for 15 min and then sprayed for 1 min every 17 min for 17 h, and vacuum packed after 48 h. Dry chilled and aged samples were suspended in refrigeration (3°C) with an air velocity of 0.25 m/s and a relative humidity of 80%. A large initial reduction of E. coli O157:H7 and Salmonella was observed, regardless of tissue type and chilling method. Fewer E. coli O157:H7 microorganisms were detected on wet chilled samples at 24 and 36 h; however, plate counts were higher from wet aged samples excised at 7 through 28 days. The final plate counts were 1.03 and 3.67 log CFU/cm2 for dry and wet aged samples, respectively. Fewer E. coli O157:H7 microorganisms were detected on fat samples from each sampling time, with the exception of 28 days, compared with lean samples. Similar trends were observed in the reduction of Salmonella for chilling or aging method and tissue type, resulting in final plate counts of 1.25 and 3.67 log CFU/cm2 for dry and wet aged samples, respectively. The findings reaffirmed wet or dry chilling and aging as potential interventions for small plants as a critical control point.

scholarly journals Detection of Escherichia coli O157:H7 and Salmonella enterica in Air and Droplets at Three U.S. Commercial Beef Processing Plants†

2012 ◽  
Vol 75 (12) ◽  
pp. 2213-2218 ◽  
Author(s):  
JOHN W. SCHMIDT ◽  
TERRANCE M. ARTHUR ◽  
JOSEPH M. BOSILEVAC ◽  
NORASAK KALCHAYANAND ◽  
TOMMY L. WHEELER
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Published Data ◽  
Escherichia Coli O157 ◽  
Liquid Droplets ◽  
Air Samples ◽  
E Coli ◽  
Beef Processing ◽  
Processing Plants ◽  
Plate Counts

Bacteria are known to be present in the air at beef processing plants, but published data regarding the prevalences of airborne Escherichia coli O157:H7 and Salmonella enterica are very limited. To determine if airborne pathogens were present in beef processing facilities, we placed sedimentation sponges at various locations in three commercial beef plants that processed cattle from slaughter through fabrication. For the 291 slaughter area air samples, E. coli O157:H7 was isolated from 15.8% and S. enterica from 16.5%. Of the 113 evisceration area air samples, E. coli O157:H7 was isolated from only one sample and S. enterica was not isolated from any sample. Pathogens were not isolated from any of the 87 air samples from fabrication areas. Pathogen prevalences, aerobic plate counts, and Enterobacteriaceae counts were highest for air samples obtained from locations near hide removal operations. The process of hide removal disperses liquid droplets, which may contact neighboring carcasses. Samples were obtained both from hide removal locations that were close enough to hide pullers to be contacted by droplets and from locations that were not contacted by droplets. Higher pathogen prevalences, aerobic plate counts, and Enterobacteriaceae counts were observed at locations with samples contacted by the hide removal droplets. We conclude that the hide removal processes likely introduce pathogens into the air via a dispersion of liquid droplets and that these droplets may be an underappreciated source of hide-to-carcass contamination.

ColiComplete® Substrate-Supporting Disc Method for Confirmed Detection of Total Coliforms and Escherichia coli in All Foods: Comparative Study

1994 ◽  
Vol 77 (1) ◽  
pp. 58-63 ◽  
Author(s):  
Philip T Feldsine ◽  
Maria T Falbo-Nelson ◽  
David L Hustead
Keyword(s):  
Escherichia Coli ◽  
Comparative Study ◽  
Total Coliform ◽  
Coliform Bacteria ◽  
Most Probable Number ◽  
Probable Number ◽  
Total Coliforms ◽  
E Coli ◽  
Total Coliform Bacteria ◽  
Better Than

Abstract The ColiComplete® substrate-supporting disc (SSD) method for simultaneous confirmed total coliform count and Escherichia coli determination in all foods was compared with the AOAC most probable number (MPN) methods 966.23 and 966.24. In this comparative study, 20 water and food types were analyzed; 7 of these foods were naturally contaminated with coliform bacteria, 6 food types were naturally contaminated with E. coli, and the remaining foods were inoculated with coliform bacteria and/or E. coli. Data were analyzed separately for total coliform bacteria and for E. coli. Mean log MPN counts were determined by the SSD method and the appropriate AOAC MPN procedure. Results were then analyzed for mean log MPN differences and variance, according to methods described by AOAC INTERNATIONAL Results for both total conforms and E. coli indicate that the SSD method is equivalent to or better than AOAC MPN methods 966.23 and 966.24.

Draft Risk Assessment of the Public Health Impact of Escherichia coli O157:H7 in Ground Beef

2004 ◽  
Vol 67 (9) ◽  
pp. 1991-1999 ◽  
Author(s):  
E. EBEL ◽  
W. SCHLOSSER ◽  
J. KAUSE ◽  
K. ORLOSKI ◽  
T. ROBERTS ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Human Exposure ◽  
Ground Beef ◽  
Health Impact ◽  
Escherichia Coli O157 ◽  
Exposure Risk ◽  
Seasonal Differences ◽  
The Public ◽  
E Coli ◽  
Number Of Cells

An assessment of the risk of illness associated with Escherichia coli O157:H7 in ground beef was drafted in 2001. The exposure assessment considers farm, slaughter, and preparation factors that influence the likelihood of humans consuming ground beef servings containing E. coli O157:H7 and the number of cells in a contaminated serving. Apparent seasonal differences in prevalence of cattle infected with E. coli O157:H7 corresponded to seasonal differences in human exposure. The model predicts that on average 0.018% of servings consumed during June through September and 0.007% of servings consumed during the remainder of the year are contaminated with one or more E. coli O157:H7 cells. This exposure risk is combined with the probability of illness given exposure (i.e., dose response) to estimate a U.S. population risk of illness of nearly one illness in each 1 million (9.6 × 10−7) servings of ground beef consumed. Uncertainty about this risk ranges from about 0.33 illness in every 1 million ground beef servings at the 5th percentile to about two illnesses in every 1 million ground beef servings at the 95th percentile.

The influence of increasing numbers of nonindicator organisms upon the detection of indicator organisms by the membrane filter and presence–absence tests

1980 ◽  
Vol 26 (7) ◽  
pp. 827-832 ◽  
Author(s):  
James A. Clark
Keyword(s):  
Membrane Filter ◽  
Total Coliform ◽  
Plate Count ◽  
Indicator Organisms ◽  
Isolation Technique ◽  
Total Coliforms ◽  
Inhibition Effect ◽  
Counting Range ◽  
Plate Counts ◽  
Better Than

Municipal water samples were analyzed by membrane filter (MF) procedures for total coliforms, "background" counts, and 24-and 48-h, 35 °C plate counts. Presence–absence (P–A) tests were done on the samples for total coliforms and other indicator bacteria. The frequency of detection of indicator organisms by P–A tests was better than twice that recovered by MF analyses. When the 24-h plate count data were grouped into counting ranges of 0, 1–100, 101–1000, and > 1000, a marked inhibition effect was observed with total coliform MF recoveries on samples producing plate counts > 1000/mL. When the "background" and 48-h plate count results were placed in the corresponding counting ranges, inhibition of indicator organisms in the total coliform MF analyses was not observed. No inhibition effect was observed in the recovery of indicator organisms by P–A tests at any of the counting range levels. The presence of an apparent inhibition effect by high numbers of bacteria in a sample was shown to be influenced by the incubation period and type of count parameter, as well as the isolation technique for detection of indicator organisms.

Survival of Escherichia coli O157:H7 in Set Yogurt as Influenced by the Production of an Exopolysaccharide, Colanic Acid

2004 ◽  
Vol 67 (2) ◽  
pp. 252-255 ◽  
Author(s):  
SHIAO MEI LEE ◽  
JINRU CHEN
Keyword(s):  
Escherichia Coli ◽  
Culture Media ◽  
Starter Cultures ◽  
Escherichia Coli O157 ◽  
Acidic Polysaccharide ◽  
E Coli ◽  
Colanic Acid ◽  
Plate Counts ◽  
Processing And Storage ◽  
And Storage

Previous studies conducted in our laboratory revealed that Escherichia coli O157:H7 cells capable of producing colanic acid (CA), the acidic polysaccharide of mucoid slime, had increased tolerance to sublethal heat and the extreme pH of microbiological culture media. This study was undertaken to determine the effect of CA on the fate of E. coli O157:H7 during the processing and storage of an acid food: yogurt. Pasteurized and homogenized whole milk was inoculated with a wild-type E. coli O157:H7, its CA-deficient mutant, or a mixture (1:1) of the two strains. Set yogurt was processed from the contaminated milk and stored at 4° and 15°C for 3 weeks. Samples of milk and yogurt were withdrawn during processing and storage and analyzed for total plate counts and populations of E. coli O157:H7 and starter cultures. The results showed that E. coli O157: H7 survived longer in yogurt stored at 15°C than at 4°C. Cells of E. coli O157:H7 deficient in CA production died off more rapidly than those of the parent strain. This suggests that CA plays a role in protecting cells of E. coli O157:H7 from stress during the processing and storage of set yogurt.

Comparison of Sponging and Excising as Sampling Procedures for Microbiological Analysis of Fresh Beef-Carcass Tissue

1999 ◽  
Vol 62 (11) ◽  
pp. 1255-1259 ◽  
Author(s):  
LORENZO M. WARE ◽  
MINDY L. KAIN ◽  
JOHN N. SOFOS ◽  
KEITH E. BELK ◽  
GARY C. SMITH
Keyword(s):  
Escherichia Coli ◽  
Acetic Acid ◽  
Cell Suspension ◽  
Total Coliform ◽  
Microbiological Analysis ◽  
Sample Storage ◽  
E Coli ◽  
Plate Counts ◽  
Sampling Procedures ◽  
Beef Carcass

Sponging and excising were evaluated as sampling procedures for microbiological analysis of beef-carcass tissue. Brisket tissue portions (10 × 10 cm) were inoculated with 2 ml of an Escherichia coli ATCC 25922 cell suspension (3 × 108 CFU/ml). After 30 min, the portions were sampled by excising (EX) or swabbing (SP) with a sterile sponge and were analyzed for aerobic plate counts on tryptic soy agar and for total coliform counts and E. coli counts on Petrifilm E. coli count plates. Another set of inoculated samples was analyzed after being spray washed, in sequence, with water (6 s, 35°C, 3.4 bar), acetic acid (2%, 6 s, 35°C, 2.1 bar), water (20 s, 42°C, 20.7 bar), and acetic acid (2%, 6 s, 35°C, 2.1 bar). Additional samples were sampled for analysis after chilling at 7°C for 24 h. Bacterial counts recovered were influenced (P ≤ 0.05) by procedure of sampling (EX versus SP), time of sampling (0.5 versus 24 h), and by their interactions. Counts recovered 0.5 h after inoculation from unwashed or spray-washed samples were similar between the two sampling procedures (EX and SP). However, counts recovered after 24 h of sample storage were significantly (P ≤ 0.05) lower for the SP compared with the EX procedure. The results indicated that as the carcass tissue was stored, recovery of bacteria by SP was less efficient than was recovery by EX.

Chemical Dehairing of Bovine Skin To Reduce Pathogenic Bacteria and Bacteria of Fecal Origin†

1998 ◽  
Vol 61 (5) ◽  
pp. 623-625 ◽  
Author(s):  
A. CASTILLO ◽  
J. S. DICKSON ◽  
R. P. CLAYTON ◽  
L. M. LUCIA ◽  
G. R. ACUFF
Keyword(s):  
Escherichia Coli ◽  
Detection Limit ◽  
Pathogenic Bacteria ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Final Count ◽  
Before And After ◽  
Plate Counts ◽  
Bovine Hide ◽  
Bovine Feces

A Chemical dehairing process was applied to artificially contaminated bovine hide to evaluate the effect on populations of Escherichia coli O157:H7 and Salmonella Typhimurium, as well as other strains of E. coli, total coliforms, and aerobic plate counts (APC). Pieces of hide (4 cm2) were contaminated with bovine feces inoculated with both rifampicin-resistant E. coli O157:H7 and S. Typhimurium to yield a final count of each pathogen of ca. 5.0 log10 CFU/cm2, or with noninoculated feces which produced an approximate final APC of 6.0 log10 CFU/cm2 and a coliform and E. coli count of 5.0 log10 CFU/cm2. Counts of pathogens, APC, coliforms, and E. coli were conducted before and after applying the dehairing treatment. S. Typhimurium and E. coli O157:H7 populations were significantly reduced from initial numbers (5.1 to 5.3 log10 CFU/cm2) to levels below the detection limit of 0.5 log10 CFU/cm2 after Chemical dehairing. APC, coliforms, and E. coli counts were also reduced significantly after dehairing, with reductions of 3.4 for APC, 3.9 for coliforms, and &gt;4.3 log10 CFU/cm2 for other E. coli strains. Since the hide is a major source of fecal contamination of beef carcass surfaces, Chemical dehairing may be beneficial in reducing overall contamination of carcasses.

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