scholarly journals Determination of the Sensitivity of a RapidEscherichia coli O157:H7 Assay for Testing 375-Gram Composite Samples

2000 ◽  
Vol 66 (9) ◽  
pp. 4149-4151 ◽  
Author(s):  
Wan-Ling Tsai ◽  
Cynthia E. Miller ◽  
Edward R. Richter
Keyword(s):  
Escherichia Coli ◽  
Sample Size ◽  
Ground Beef ◽  
Immunomagnetic Separation ◽  
Enzyme Linked Immunosorbent Assay ◽  
Elisa System ◽  
Composite Ground ◽  
Single Size ◽  
Composite Samples

ABSTRACT Both 25-g single-size ground beef samples and 375-g composite ground beef samples were tested by a method combining an immunomagnetic separation (IMS) technique with a sandwich enzyme-linked immunosorbent assay (ELISA) system (IMS-ELISA). The results demonstrated that IMS-ELISA could detect the target, Escherichia coliO157:H7, at the level of 10−1 CFU/g of sample in either the 25- or 375-g sample size.

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.

Detection of Escherichia coli O157:H7 in ground beef using immunomagnetic separation and multiplex PCR

Food Control ◽  
2009 ◽  
Vol 20 (4) ◽  
pp. 357-361 ◽  
Author(s):  
Belgin Sarimehmetoglu ◽  
Mihriban Hatun Aksoy ◽  
Naim Deniz Ayaz ◽  
Yildiz Ayaz ◽  
Ozlem Kuplulu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Ground Beef ◽  
Immunomagnetic Separation ◽  
Escherichia Coli O157

scholarly journals Modeling and Predicting the Simultaneous Growth of Escherichia coli O157:H7 and Ground Beef Background Microflora for Various Enrichment Protocols

2006 ◽  
Vol 72 (1) ◽  
pp. 261-268 ◽  
Author(s):  
A. Vimont ◽  
C. Vernozy-Rozand ◽  
M. P. Montet ◽  
C. Lazizzera ◽  
C. Bavai ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Incubation Temperature ◽  
Basal Medium ◽  
Ground Beef ◽  
Immunomagnetic Separation ◽  
Enrichment Factors ◽  
Screening Methods ◽  
Competitive Growth ◽  
Enrichment Protocol ◽  
Simultaneous Growth

ABSTRACT The simultaneous growth of Escherichia coli O157:H7 (O157) and the ground beef background microflora (BM) was described in order to characterize the effects of enrichment factors on the growth of these organisms. The different enrichment factors studied were basal medium (Trypticase soy broth and E. coli broth), the presence of novobiocin in the broth, and the incubation temperature (37°C or 40°C). BM and O157 kinetics were simultaneously fitted by using a competitive growth model. The simple competition between the two microfloras implied that O157 growth stopped as soon as the maximal bacterial density in the BM was reached. The present study shows that the enrichment protocol factors had little impact on the simultaneous growth of BM and O157. The selective factors (i.e., bile salts and novobiocin) and the higher incubation temperature (40°C) did not inhibit BM growth, and incubation at 40°C only slightly improved O157 growth. The results also emphasize that when the level of O157 contamination in ground beef is low, the 6-h enrichment step recommended in the immunomagnetic separation protocol (ISO EN 16654) is not sufficient to detect O157 by screening methods. In this case, prior enrichment for approximately 10 h appears to be the optimal duration for enrichment. However, more experiments must be carried out with ground beef packaged in different ways in order to confirm the results obtained in the present study for non-vacuum- and non-modified-atmosphere-packed ground beef.

Rapid Detection of Salmonella enteritidis in Pooled Liquid Egg Samples Using a Magnetic Bead-ELISA System

1995 ◽  
Vol 58 (9) ◽  
pp. 967-972 ◽  
Author(s):  
PETER S. HOLT ◽  
RICHARD K. GAST ◽  
CAM R. GREENE
Keyword(s):  
Salmonella Enteritidis ◽  
Magnetic Bead ◽  
Immunomagnetic Separation ◽  
Detection Methods ◽  
Enzyme Linked Immunosorbent Assay ◽  
Direct Plating ◽  
Elisa System ◽  
Low Concentrations ◽  
Standard Assay ◽  
Flagellar Proteins

An assay was developed to shorten the time necessary to detect Salmonella enteritidis (SE) in contaminated egg pools. The immunomagnetic separation (IMS)-based assay used the DynabeadsTM Anti-Salmonella, a magnetic bead with mouse anti-Salmonella antibodies affixed to the surface, to bind the SE in the egg pools. The bound SE were concentrated by a magnet and were detected via an enzyme-linked immunosorbent assay (ELISA) (IMS-ELISA) employing a monoclonal anti-SE flagellar proteins (flagellins) antibody. Following the ELISA, the beads were plated onto differential media (IMS-direct).The efficacy of the assay for detecting SE was compared with that of the standard assay, direct plating, in pooled egg samples spiked with low concentrations of SE and incubated at 37°C for 24 to 96 h. Conventional direct plating of egg samples required a total of 48 h before SE could be identified in egg pools, compared with 24 h for the IMS-ELISA. Plating of the beads (IMS-direct) to confirm the presence of SE required a further 24 h. The IMS-ELISA could detect SE at concentrations of 105 to 106 SE cells per ml, comparable to that shown previously for direct plating. The IMS-direct could detect SE at 104 SE cells per ml of egg pool. In egg pools initially contaminated with 10 SE cells per ml, the organism grew to levels by 24 h at 37°C where 100% of the pools were positive for SE by all three detection methods. In egg pools initially contaminated with 1 SE cell per ml, 61% of pools were detected by direct plating and IMS-ELISA and 72% were detected by IMS-direct. Similar detection frequencies were observed for a second SE isolate. The IMS-ELISA provides an SE detection rate comparable to direct plating but achieves the result 24 h sooner. The IMS-direct was the most sensitive means of detecting the SE.

Lactate Dehydrogenase Polyclonal Antibody Sandwich ELISA for Determination of Endpoint Heating Temperatures of Ground Beef

1996 ◽  
Vol 59 (1) ◽  
pp. 51-55 ◽  
Author(s):  
CHENG-HSIN WANG ◽  
MOHAMED M. ABOUZIED ◽  
JAMES J. PESTKA ◽  
DENISE M. SMITH
Keyword(s):  
Lactate Dehydrogenase ◽  
Polyclonal Antibody ◽  
Heating Temperature ◽  
Polyclonal Antibodies ◽  
Sandwich Elisa ◽  
Ground Beef ◽  
Enzyme Linked Immunosorbent Assay ◽  
Protein Marker ◽  
Beef Patties

An enzyme-linked immunosorbent assay (ELISA) for the protein marker lactate dehydrogenase (LDH) was developed to determine endpoint heating temperature (EPT) of ground beef. Ground beef was placed in 10 by 75 mm tubes and heated to temperatures between 62 and 74°C at 2°C intervals. Electrophoresis and immunoblotting of meat extracts indicated a decrease in the intensity of the LDH band as temperature was increased. Polyclonal antibodies (PAb) against bovine muscle LDH were produced and a sandwich ELISA devised using biotinylated PAb as the detecting antibody. The LDH content decreased (P < 0.05) in ground beef heated between 66 and 74°C and was less than 4 μg/g of meat at the recommended minimum endpoint of 69°C. The ELISA was used to estimate the EPT of commercially cooked beef patties.

Performance of Chromogenic Agar Media for Isolation of Shiga Toxin–Producing Escherichia coli from Ground Beef

2020 ◽  
Vol 83 (7) ◽  
pp. 1149-1154
Author(s):  
GENTRY L. LEWIS ◽  
NATALIA CERNICCHIARO ◽  
RODNEY A. MOXLEY
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Culture Media ◽  
Geometric Mean ◽  
Ground Beef ◽  
Immunomagnetic Separation ◽  
Broth Culture ◽  
True Negative ◽  
Chromogenic Agar ◽  
Agar Media

ABSTRACT The performance of three chromogenic agar media for detection of the “top seven” Shiga toxin–producing Escherichia coli (STEC) in beef was compared. Samples of retail ground beef were inoculated with STEC O26, O45, O103, O111, O121, O145, or O157 at geometric mean (±standard error of the mean) levels of 0, 48 (±1), 420 (±1), 4,100 (±1), or 45,000 (±1) CFU/10 g and enriched 1:10 (90 mL) in EC broth (40°C for 6 h). Following enrichment, aliquots of broth culture were treated by immunomagnetic separation with one of three pools of beads against the seven STEC serogroups: pool I, O26, O45, and O121; pool II, O103, O111, and O145; and pool III, O157. After immunomagnetic separation, 50 μL of washed bead suspensions in buffered peptone water were spiral plated onto modified Rainbow Agar O157 (mRBA), CHROMagar STEC (CS), or modified Possé differential medium (mPossé2) and incubated at 37°C for 18 h. Up to six isolated colonies were picked from each spiral plate based on expected colony phenotypes for STEC on the respective media, and isolate identity was confirmed with an 11-plex PCR assay targeting the O serogroups and virulence genes. Overall, mRBA had the highest sensitivity (99.2%), correctly detecting a significantly higher proportion of STEC serogroups than either CS (79.4%; P < 0.05) or mPossé2 (91.7%; P < 0.05). mRBA also had the highest negative predictive value (90.0%), correctly identifying a significantly higher proportion of true-negative samples compared with CS (25.7%; P < 0.05) and mPossé2 (46.2%; P < 0.05). However, mRBA also had the lowest analytical specificity of 83.2% (P < 0.05), yielding the lowest proportion of colonies tested that were STEC positive (3,548 of 4,263) compared with 97.7% (3,607 of 3,693) for mPossé2 and 98.0% (2,875 of 2,935) for CS. Reduced specificity results in more work and higher expense due to the increased number of colonies that must be tested. Further improvements in agar culture media for non-O157 STEC isolation are needed. HIGHLIGHTS

Sign in / Sign up

Export Citation Format

Share Document