Effect of a Vaccine Product Containing Type III Secreted Proteins on the Probability of Escherichia coli O157:H7 Fecal Shedding and Mucosal Colonization in Feedlot Cattle†

2007 ◽  
Vol 70 (11) ◽  
pp. 2568-2577 ◽  
Author(s):  
R. E. PETERSON ◽  
T. J. KLOPFENSTEIN ◽  
R. A. MOXLEY ◽  
G. E. ERICKSON ◽  
S. HINKLEY ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Humoral Response ◽  
Immunomagnetic Separation ◽  
Environmental Safety ◽  
Feedlot Cattle ◽  
Escherichia Coli O157 ◽  
Selective Enrichment ◽  
E Coli ◽  
Natural Exposure ◽  
Vaccine Product

Preharvest intervention strategies to reduce Escherichia coli O157:H7 in cattle have been sought as a means to reduce human foodborne illness. A blinded clinical trial was conducted to test the effect of a vaccine product on the probability that feedlot steers, under conditions of natural exposure, shed E. coli O157:H7 in feces, are colonized by this organism in the terminal rectum, or develop a humoral response to the respective antigens. Steers (n = 288) were assigned randomly to 36 pens (eight head per pen), and pens were randomized to vaccination treatment in a balanced fashion within six dietary treatments of an unrelated nutrition study. Treatments included vaccination or placebo (three doses at 3-week intervals). Fecal samples for culture (n = 1,410) were collected from the rectum of each steer on pretreatment day 0 and posttreatment days 14, 28, 42, and 56. Terminal rectum mucosal (TRM) cells were aseptically collected for culture at harvest (day 57 posttreatment) by scraping the mucosa 3.0 to 5.5 cm proximal to the rectoanal junction. E. coli O157:H7 was isolated and identified with selective enrichment, immunomagnetic separation, and PCR confirmation. Vaccinated cattle were 98.3% less likely to be colonized by E. coli O157:H7 in TRM cells (odds ratio = 0.014, P < 0.0001). Diet was also associated with the probability of cattle being colonized (P = 0.04). Vaccinated cattle demonstrated significant humoral responses to Tir and O157 lipopolysaccharide. These results provide evidence that this vaccine product reduces E. coli O157:H7 colonization of the terminal rectum of feedlot beef cattle under conditions of natural exposure, a first step in its evaluation as an effective intervention for food and environmental safety.

Effect of Lactobacillus acidophilus Strain NP51 on Escherichia coli O157:H7 Fecal Shedding and Finishing Performance in Beef Feedlot Cattle†

2007 ◽  
Vol 70 (2) ◽  
pp. 287-291 ◽  
Author(s):  
R. E. PETERSON ◽  
T. J. KLOPFENSTEIN ◽  
G. E. ERICKSON ◽  
J. FOLMER ◽  
S. HINKLEY ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactobacillus Acidophilus ◽  
Repeated Measures ◽  
Immunomagnetic Separation ◽  
Feedlot Cattle ◽  
Outcome Variable ◽  
Escherichia Coli O157 ◽  
Fecal Shedding ◽  
Selective Enrichment ◽  
E Coli

A 2-year study was conducted during the summer months (May to September) to test the effectiveness of feeding Lactobacillus acidophilus strain NP51 on the proportion of cattle shedding Escherichia coli O157:H7 in the feces and evaluate the effect of the treatment on finishing performance. Steers (n = 448) were assigned randomly to pens, and pens of cattle were assigned randomly to NP51 supplementation or no supplementation (control). NP51 products were mixed with water and applied as the feed was mixed daily in treatment-designated trucks at the rate of 109 CFU per steer. Fecal samples were collected (n = 3,360) from the rectum from each animal every 3 weeks, and E. coli O157:H7 was isolated by standard procedures, using selective enrichment, immunomagnetic separation, and PCR confirmation. The outcome variable was the recovery of E. coli O157:H7 from feces, and was modeled using logistic regression accounting for year, repeated measures of pens of cattle, and block. No significant differences were detected for gain, intakes, or feed efficiency of control or NP51-fed steers. The probability for cattle to shed E. coli O157:H7 varied significantly between 2002 and 2003 (P = 0.004). In 2002 and 2003, the probability for NP51-treated steers to shed E. coli O157:H7 over the test periods was 13 and 21%, respectively, compared with 21 and 28% among controls. Over the 2 years, NP51-treated steers were 35% less likely to shed E. coli O157: H7 than were steers in untreated pens (odds ratio = 0.58, P = 0.008). This study is consistent with previous reports that feeding NP51 is effective in reducing E. coli O157:H7 fecal shedding in feedlot cattle.

Prevalence and Enumeration of Escherichia coli O157 in Steers Receiving Various Strains of Lactobacillus-Based Direct-Fed Microbials

2007 ◽  
Vol 70 (5) ◽  
pp. 1252-1255 ◽  
Author(s):  
T. P. STEPHENS ◽  
G. H. LONERAGAN ◽  
L. M. CHICHESTER ◽  
M. M. BRASHEARS
Keyword(s):  
Escherichia Coli ◽  
Lactobacillus Acidophilus ◽  
Immunomagnetic Separation ◽  
Feedlot Cattle ◽  
Most Probable Number ◽  
Escherichia Coli O157 ◽  
Feeding Period ◽  
Probable Number ◽  
Selective Enrichment ◽  
E Coli

The objective of this research was to evaluate the effect of daily dietary inclusion of specific strains of Lactobacillus acidophilus on prevalence and concentration of Escherichia coli O157 in harvest-ready feedlot cattle. Five hundred yearling steers were housed in pens of 10 animals each. At arrival, steers were randomly allocated to one of five cohorts. Four of the cohorts were fed various strains and dosages of Lactobacillus-based direct-fed microbials throughout the feeding period. Fecal samples were collected from the rectum of each animal immediately prior to shipment to the abattoir. E. coli O157 was detected using selective enrichment and immunomagnetic separation techniques. For positive samples, E. coli O157 concentration was estimated using a most-probable-number (MPN) technique that included immunomagnetic separation. Prevalence varied among the cohorts (P < 0.01). The prevalence in the controls (26.3%) was greater (P < 0.05) than that in cattle supplemented with L. acidophilus strains NP51, NP28, or NP51-NP35 (13.0, 11.0, and 11.0%, respectively). The greatest E. coli O157 concentration was also observed in the controls (3.2 log MPN/g of feces); this concentration was greater (P < 0.05) than that observed in positive animals receiving NP51, NP28, or NP51-NP35 (0.9, 1.1, 1.7 log MPN/g of feces, respectively). Specific strains of Lactobacillus-based direct-fed microbials effectively reduced the prevalence and concentration of E. coli O157 in harvest-ready cattle, whereas others did not. When using direct-fed microbials to reduce carriage of E. coli O157 in cattle, it is important to select appropriately validated products.

Development and Validation of a Most-Probable-Number–Immunomagnetic Separation Methodology of Enumerating Escherichia coli O157 in Cattle Feces

2007 ◽  
Vol 70 (5) ◽  
pp. 1072-1075 ◽  
Author(s):  
T. P. STEPHENS ◽  
G. H. LONERAGAN ◽  
W. E. CHANEY ◽  
L. A. BRANHAM ◽  
M. M. BRASHEARS
Keyword(s):  
Escherichia Coli ◽  
Immunomagnetic Separation ◽  
Feedlot Cattle ◽  
Most Probable Number ◽  
Escherichia Coli O157 ◽  
Probable Number ◽  
Direct Plating ◽  
Fecal Samples ◽  
E Coli ◽  
The Difference

A method to validate enumeration of Escherichia coli O157 in fecal samples from feedlot cattle was developed in these studies. Due to background flora, bovine fecal sample enumeration cannot be performed by simple direct plating techniques. Known quantities of E. coli O157:H7 were inoculated into feces, and populations were determined by direct plating of the cocktail (studies 1, 2, and 3) and manure and cocktail (studies 4 and 5) mixtures and compared with a most-probable-number (MPN)–immunomagnetic separation (IMS) method. The three-tube MPN combined preenrichment in gram-negative broth with confirmation using IMS. Five separate enumeration studies (study 1, sterile feces inoculated with 102 E. coli O157:H7 per g; study 2, nonsterile feces inoculated with 103 E. coli O157:H7 per g; study 3, nonsterile feces inoculated with 101 E. coli O157:H7 per g; study 4, sterile feces inoculated with 104 streptomycin-resistant E. coli O157:H7 per g; and study 5, sterile feces inoculated with 102 streptomycin-resistant E. coli O157:H7 per g) were conducted. These studies were performed to determine the precision, accuracy, and specificity at low and high levels of pathogen contamination in feces, using direct plating compared with the MPN-IMS methodology tested. There was an overall difference (P < 0.01) between direct plating and MPN-IMS methodologies, but this difference was biologically negligible due to the difference in least-squares means (0.29 ± 0.10) being so low. The direct plating and MPN-IMS methods were correlated (r = 0.93). These results suggest that using the MPN-IMS procedures is an effective method of estimating E. coli O157 populations in naturally infected bovine fecal samples.

Dietary Supplementation with Lactobacillus- and Propionibacterium-Based Direct-Fed Microbials and Prevalence of Escherichia coli O157 in Beef Feedlot Cattle and on Hides at Harvest

2004 ◽  
Vol 67 (5) ◽  
pp. 889-893 ◽  
Author(s):  
S. M. YOUNTS-DAHL ◽  
M. L. GALYEAN ◽  
G. H. LONERAGAN ◽  
N. A. ELAM ◽  
M. M. BRASHEARS
Keyword(s):  
Escherichia Coli ◽  
Intervention Strategy ◽  
Immunomagnetic Separation ◽  
Feedlot Cattle ◽  
High Dose ◽  
Standard Diet ◽  
Escherichia Coli O157 ◽  
Feeding Period ◽  
E Coli ◽  
Finishing Beef Cattle

The objective of this study was to describe the prevalence of Escherichia coli O157 in the feces and on the hides of finishing beef cattle fed a standard diet and those fed diets supplemented with direct-fed microbials. Two hundred forty steers received one of four treatments throughout the feeding period: (i) control: no added microbials; (ii) HNP51: high dose of Lactobacillus acidophilus strain NP 51 (109 CFU per steer daily) and Propionibacterium freudenreichii (109 CFU per steer daily); (iii) HNP51+45: high dose of NP 51 (109 CFU per steer daily), P. freudenreichii (109 CFU per steer daily), and L. acidophilus NP 45 (106 CFU per steer daily); or (iv) LNP51+ 45: low dose of NP 51 (106 CFU per steer daily), P. freudenreichii (109 CFU per steer daily), and NP 45 (106 CFU per steer daily). Samples were collected from each animal and analyzed for the presence of E. coli O157 using immunomagnetic separation methods on day 0 (feces), 7 days before harvest (feces), and at harvest (feces and hide). At the end of the feeding period, cattle receiving HNP51 were 57% less likely to shed detectable E. coli O157 in their feces than were the controls (P < 0.01). For animals receiving HNP51+ 45 and LNP51+ 45, fecal prevalence did not differ from that of the controls. The prevalence of positive hide samples was least among cattle receiving HNP51+ 45 (3.3%); these animals were 79% less likely (P < 0.06) to have a positive hide sample than were the controls (prevalence = 13.8%). There was poor agreement of the culture results between fecal and hide samples collected from the same animal (κ = 0.08; confidence interval = −0.05 to 0.2). Cattle supplemented with a high dose of NP 51 had reduced E. coli O157 prevalence in both fecal and hide samples, indicating that this treatment may be an efficacious preharvest intervention strategy.

Reduction of Escherichia coli O157 and Salmonella in Feces and on Hides of Feedlot Cattle Using Various Doses of a Direct-Fed Microbial

2007 ◽  
Vol 70 (10) ◽  
pp. 2386-2391 ◽  
Author(s):  
T. P. STEPHENS ◽  
G. H. LONERAGAN ◽  
E. KARUNASENA ◽  
M. M. BRASHEARS
Keyword(s):  
Escherichia Coli ◽  
Low Dose ◽  
Immunomagnetic Separation ◽  
Feedlot Cattle ◽  
High Dose ◽  
Escherichia Coli O157 ◽  
Propionibacterium Freudenreichii ◽  
E Coli ◽  
High Doses ◽  
Medium Dose

In this study, the effectiveness of direct-fed microbials at reducing Escherichia coli O157 and Salmonella in beef cattle was evaluated. Steers (n = 240) received one of the following four treatment concentrations: control = lactose carrier only; low = 1 × 107 CFU per steer daily Lactobacillus acidophilus NP51; medium = 5 × 108 CFU per steer daily L. acidophilus NP51; and high = 1 × 109 CFU per steer daily L. acidophilus NP51. Low, medium, and high diets also included 1 × 109 CFU per steer Propionibacterium freudenreichii NP24. Feces were collected from each animal at allocation of treatment and found to have no variation (P = 0.54) between cohorts concerning E. coli O157 recovery. Feces and hide swabs were collected at harvest and analyzed for the presence of E. coli O157 by immunomagnetic separation and Salmonella by PCR. No significant dosing effects were detected for E. coli O157 recovery from feces at the medium dose or from hides at the medium and high doses. E. coli O157 was 74% (P < 0.01) and 69% (P < 0.01) less likely to be recovered in feces from animals receiving the high and low diets, respectively, compared with controls. Compared with controls, E. coli O157 was 74% (P = 0.05) less likely to be isolated on hides of cattle receiving the low dose. No significant dosing effects were detected for Salmonella recovery from feces at the medium and low doses or from hides at any doses. Compared with controls, Salmonella was 48% (P = 0.09) less likely to be shed in feces of cattle receiving the high dose. No obvious dose-response of L. acidophilus NP51 on recovery of E. coli O157 or Salmonella was detected in our study.

An Improved Rapid Technique for Isolation of Escherichia coli O157:H7 from Foods

1995 ◽  
Vol 58 (1) ◽  
pp. 7-12 ◽  
Author(s):  
STEPHEN D. WEAGANT ◽  
JAMES L. BRYANT ◽  
KAREN G. JINNEMAN
Keyword(s):  
Escherichia Coli ◽  
Comparative Method ◽  
Immunomagnetic Separation ◽  
Latex Agglutination ◽  
Escherichia Coli O157 ◽  
Biochemical Tests ◽  
Isolation Technique ◽  
Selective Enrichment ◽  
E Coli ◽  
Polymerase Chain

A newly revised enrichment and agar-plating system was tested for selectivity and sensitivity in recovery of unstressed and cold-stressed Escherichia coli O157:H7 from foods. Various foods inoculated with known levels of enterohemorrhagic E. coli O157:H7 (EHEC) were tested by enrichment for 6 h at 37°C in modified tryptic soy broth (mTSB) base supplemented with vancomycin, cefsulodin and cefixime, referred to as EHEC enrichment broth (EEB). Subsequently, portions were spread-plated on sorbitol–MacConkey agar supplemented with tellurite and cefixime (TCSMAC). Further selective enrichment was also examined using immunomagnetic separation (IMS) from the EEB prior to spread-plating on TCSMAC agar. These methods were compared to a procedure of enrichment in mTSB (supplemented with novobiocin) at 37°C for 24 h followed by spread-plating of decimal dilutions on hemorrhagic colitis 4–methylumbelliferyl–B–D–glucuronide (HC–MUG) agar. The new enrichment isolation technique was found to be sensitive at a level of one EHEC organism per 10 g of food in four food types. This represents an approximate l00-fold to 1,000-fold enhancement in sensitivity over the comparative method for foods with high levels of competitive microflora. These enrichment-isolation protocols also were compared in analysis of naturally contaminated raw or undercooked ground beef samples implicated in foodborne illness. EEB-TCSMAC with and without IMS were combined with rapid biochemical tests, and with O157 latex agglutination and confirmation of toxin genes by polymerase chain reaction (PCR) to provide a completed test within 30 h of initiating testing. The new system was successful in 15 of 17 samples, where only 6 of 17 were found positive by the comparative technique.

Screening Bovine Carcass Sponge Samples for Escherichia coli O157 Using a Short Enrichment Coupled with Immunomagnetic Separation and a Polymerase Chain Reaction–Based (BAX) Detection Step†

2001 ◽  
Vol 64 (10) ◽  
pp. 1610-1612 ◽  
Author(s):  
DONG-HYUN KANG ◽  
GENEVIEVE A. BARKOCY-GALLAGHER ◽  
MOHAMMAD KOOHMARAIE ◽  
GREGORY R. SIRAGUSA
Keyword(s):  
Escherichia Coli ◽  
Culture Method ◽  
Immunomagnetic Separation ◽  
Escherichia Coli O157 ◽  
Chain Reaction ◽  
Selective Enrichment ◽  
E Coli ◽  
Screening Protocol ◽  
Polymerase Chain ◽  
Culture Positive

A bovine carcass sponge sample screening protocol for detecting Escherichia coli O157:H7 was composed of a short selective enrichment followed by an immunomagnetic separation (IMS) and target detection using the BAX E. coli O157 polymerase chain reaction assay. This screening protocol was compared to a culture-based method for detection of the organism in carcass sponge samples. Enriched samples were subjected to IMS; the bead suspension was divided and plated on selected media or stored at −20°C, then subjected to BAX analysis. The results showed a high degree of agreement between the plating method and the BAX system. Fifty-two of the 59 culture-positive samples were also positive using the BAX system (88.1% sensitivity). Of the 76 samples that appeared negative for the presence of E. coli O157:H7 by the culture method, 66 were determined as negative using the BAX system (86.8% specificity). Four of the 10 samples found negative by the initial culture method and positive by the BAX method were subsequently found to be culture positive upon reanalysis. Based on these data, the BAX system combined with a short, selective enrichment and IMS may be a rapid, reliable, and simple method to screen for E. coli O157:H7 in carcass sponge samples. Our data indicate that optimization and subsequent testing of this protocol for use as a carcass screening tool are warranted.

Efficacy of Dose Regimen and Observation of Herd Immunity from a Vaccine against Escherichia coli O157:H7 for Feedlot Cattle†

2007 ◽  
Vol 70 (11) ◽  
pp. 2561-2567 ◽  
Author(s):  
R. E. PETERSON ◽  
T. J. KLOPFENSTEIN ◽  
R. A. MOXLEY ◽  
G. E. ERICKSON ◽  
S. HINKLEY ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Repeated Measures ◽  
Fixed Effects ◽  
Herd Immunity ◽  
Feedlot Cattle ◽  
External Control ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Feedlot Steers ◽  
Vaccine Product

A clinical trial was conducted to test the effect of a vaccine product containing type III secreted proteins of Escherichia coli O157:H7 on the probability that feedlot steers shed E. coli O157:H7 in feces. Six hundred eight same-source steers were utilized. Of these, 480 steers were assigned randomly to 60 pens (eight head per pen) and to one of four vaccination treatments (120 cattle per treatment, two head per treatment per pen). The four treatments were (i) no vaccination; (ii) one dose, vaccinated once at reimplant (day 42); (iii) two doses, vaccinated on arrival (day 0) and again at reimplant (day 42); and (iv) three doses, vaccinated on arrival (day 0), on day 21, and again at reimplant (day 42). The remaining 128 steers were assigned randomly to 12 pens within the same feedlot to serve as unvaccinated external controls. The probability of detecting E. coli O157:H7 among cattle receiving different doses of vaccine was compared with that of unvaccinated external control cattle, accounting for clustering by repeated measures, block, and pen and fixed effects of vaccine, corn product, and test period. Vaccine efficacy of receiving one, two, and three doses of vaccine was 68, 66, and 73%, respectively, compared with cattle in pens not receiving vaccine. Cattle receiving three doses of vaccine were significantly less likely to shed E. coli O157:H7 than unvaccinated cattle within the same pen. Unvaccinated cattle housed with vaccinated cattle were 59% less likely to shed E. coli O157:H7 than cattle in pens not receiving vaccine, likely because they benefited from herd immunity. This study supports the hypothesis that vaccination with this vaccine product effectively reduces the probability for cattle to shed E. coli O157:H7. There was no indication that the vaccine affected performance or carcass quality. In addition, we found that vaccinating a majority of cattle within a pen offered a significant protective effect (herd immunity) to unvaccinated cattle within the same pen.

Monitoring Escherichia coli O157:H7 in Inoculated and Naturally Colonized Feedlot Cattle and Their Environment

2005 ◽  
Vol 68 (1) ◽  
pp. 26-33 ◽  
Author(s):  
K. STANFORD ◽  
S. J. BACH ◽  
T. H. MARX ◽  
S. JONES ◽  
J. R. HANSEN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Feedlot Cattle ◽  
Mitigation Strategies ◽  
Escherichia Coli O157 ◽  
Feeding Period ◽  
Sample Collection ◽  
E Coli ◽  
Challenge Study ◽  
On Farm ◽  
Feed Samples

On-farm methods of monitoring Escherichia coli O157:H7 were assessed in 30 experimentally inoculated steers housed in four pens over a 12-week period and in 202,878 naturally colonized feedlot cattle housed in 1,160 pens on four commercial Alberta feedlots over a 1-year period. In the challenge study, yearling steers were experimentally inoculated with 1010 CFU of a four-strain mixture of nalidixic acid–resistant E. coli O157:H7. After inoculation, shedding of E. coli O157:H7 was monitored weekly by collecting rectal fecal samples (FEC), oral swabs (ORL), pooled fecal pats (PAT), manila ropes (ROP) orally accessed for 4 h, feed samples, water, and water bowl interface. Collection of FEC from all animals per pen provided superior isolation (P < 0.01) of E. coli O157:H7 compared with other methods, although labor and animal restraint requirements for fecal sample collection were high. When one sample was collected per pen of animals, E. coli O157:H7 was more likely to be detected from the ROP than from the FEC, PAT, or ORL (P < 0.001). In the commercial feedlot study, samples were limited to ROP and PAT, and E. coli O157:H7 was isolated in 18.8% of PAT and 6.8% of ROP samples. However, for animals that had been resident in the feedlot pen for at least 1 month, isolation of E. coli O157:H7 from ROP was not different from that from PAT (P = 0.35). Pens of animals on feed for <30 days were six times more likely to shed E. coli O157:H7 than were animals on feed for >30 days. However, change in diet did not affect shedding of the organism (P > 0.23) provided that animals had acclimated to the feedlot for 1 month or longer. Findings from this study indicate the importance of introduction of mitigation strategies early in the feeding period to reduce transference and the degree to which E. coli O157:H7 is shed into the environment.

Comparison of Rapid Enzyme-Linked Immunosorbent Assay and Immunomagnetic Separation Methods for Detection of Escherichia coli O157 in Fecal, Hide, Carcass, and Ground Beef Samples

2007 ◽  
Vol 70 (10) ◽  
pp. 2230-2234 ◽  
Author(s):  
T. W. THOMPSON ◽  
T. P. STEPHENS ◽  
G. H. LONERAGAN ◽  
M. F. MILLER ◽  
M. M. BRASHEARS
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Immunomagnetic Separation ◽  
Separation Method ◽  
Enzyme Linked Immunosorbent Assay ◽  
Escherichia Coli O157 ◽  
Perfect Agreement ◽  
Fecal Samples ◽  
E Coli ◽  
Beef Products

Rapid enzyme-linked immunosorbent assays (ELISAs) are approved for detection of Escherichia coli O157 in beef products. However, these kits have also been used in the industry to detect this pathogen on hides or in feces of cattle, although this use has not been validated. The objective of this study was to compare commercially available ELISAs (E. coli Now, Reveal, and VIP) with immunomagnetic separation along with selective media to detect E. coli O157 on hides, in feces, and in medium- and low-level-inoculated ground beef and carcasses (simulated by using briskets) samples. Naturally infected hide and fecal samples were subjected to both the immunomagnetic separation method and ELISAs for the detection of E. coli O157. Additionally, E. coli O157 inoculated and noninoculated ground beef and beef briskets were used to simulate meat and carcass samples. When comparing the detection results from the ELISAs (E. coli Now, Reveal, and VIP) to the immunomagnetic separation method, poor agreement was observed for fecal samples (kappa = 0.10, 0.02, and 0.03 for E. coli Now, Reveal, and VIP, respectively), and fair-to-moderate agreement was observed for hide samples (kappa = 0.30, 0.51, and 0.29 for E. coli Now, Reveal, and VIP, respectively). However, there was near-perfect agreement between the immunomagnetic separation method and ELISAs for ground beef (kappa = 1, 1, and 0.80 for E. coli Now, Reveal, and VIP, respectively) and brisket (kappa = 1, 1, and 1 for E. coli Now, Reveal, and VIP, respectively) samples. Assuming immunomagnetic separation is the best available method, these data suggest that the ELISAs are not useful in detecting E. coli O157 from hide or fecal samples. However, when ELISAs are used on ground beef and beef brisket samples they can be used with a high degree of confidence.

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