Comparison of an ELISA-based Screening Test with Liquid Chromatography for the Determination of Aflatoxins in Corn

1991 ◽  
Vol 74 (5) ◽  
pp. 827-829
Author(s):  
Rodney W Beaver ◽  
Mary A James ◽  
Tay Y Lin
Keyword(s):  
Liquid Chromatography ◽  
Immunosorbent Assay ◽  
False Positive ◽  
Screening Test ◽  
False Negative ◽  
Screening Method ◽  
Incorrect Response ◽  
False Positives ◽  
Enzyme Linked Immunosorbent Assay

Abstract An enzyme-linked immunosorbent assay (ELISA) screening test (CITE PROBE) was compared to liquid chromatography (LC) for the determination of aflatoxins in naturally contaminated corn samples. The CITE PROBE, with a positive/negative cutoff of 5 ng/g aflatoxin Bi, was correct (based on LC results) on 47 of 51 samples. Two of the Incorrect responses by the CITE PROBE were false positives on samples containing 4.4 ng/g and 4.1 ng/g aflatoxins by LC. Another incorrect response was a false negative on a sample containing 5.5 ng/g aflatoxins by LC. The fourth Incorrect response was a false positive on a sample containing 1.9 ng/g aflatoxins by LC. On the basis of these results, the CITE PROBE was determined to be a reliable screening method for the detection of % 5 ng/g aflatoxins in corn.

scholarly journals Rapid Mycobacterial Liquid Culture-Screening Method for Mycobacterium avium Complex Based on Secreted Antigen-Capture Enzyme-Linked Immunosorbent Assay

2009 ◽  
Vol 16 (5) ◽  
pp. 613-620 ◽  
Author(s):  
Sung Jae Shin ◽  
Kelly Anklam ◽  
Elizabeth J. B. Manning ◽  
Michael T. Collins
Keyword(s):  
Immunosorbent Assay ◽  
Mycobacterium Avium ◽  
False Positive ◽  
High Performance ◽  
Liquid Culture ◽  
False Negative ◽  
Screening Method ◽  
Clinical Samples ◽  
Enzyme Linked Immunosorbent Assay ◽  
Specific Test

ABSTRACT Sensors in automated liquid culture systems for mycobacteria, such as MGIT, BacT/Alert 3D, and Trek ESP II, flag growth of any type of bacteria; a positive signal does not mean that the target mycobacteria are present. All signal-positive cultures thus require additional and often laborious testing. An immunoassay was developed to screen liquid mycobacterial cultures for evidence of Mycobacterium avium complex (MAC). The method, called the MAC-enzyme-linked immunosorbent assay (ELISA), relies on detection of MAC-specific secreted antigens in liquid culture. Secreted MAC antigens were captured by the MAC-ELISA with polyclonal anti- Mycobacterium avium subsp. paratuberculosis chicken immunoglobulin Y (IgY), detected using rabbit anti-MAC IgG, and then revealed using horseradish peroxidase-conjugated goat anti-rabbit IgG. When the MAC-ELISA was evaluated using pure cultures of known mycobacterial (n = 75) and nonmycobacterial (n = 17) organisms, no false-positive or false-negative MAC-ELISA results were found. By receiver operator characteristic (ROC) analysis of 1,275 previously identified clinical isolates, at the assay optimal cutoff the diagnostic sensitivity and specificity of the MAC-ELISA were 92.6% (95% confidence interval [95% CI], 90.3 to 94.5) and 99.9% (95% CI, 99.2 to 100), respectively, with an area under the ROC curve of 0.992. Prospective evaluation of the MAC-ELISA with an additional 652 clinical samples inoculated into MGIT ParaTB medium and signaling positive per the manufacturer's instructions found that the MAC-ELISA was effective in determining those cultures that actually contained MAC species and warranting the resources required to identify the organism by PCR. Of these 652 MGIT-positive cultures, the MAC-ELISA correctly identified 96.8% (of 219 MAC-ELISA-positive cultures) as truly containing MAC mycobacteria, based on PCR or high-performance liquid chromatography (HPLC) as reference tests. Only 6 of 433 MGIT signal-positive cultures (1.4%) were MAC-ELISA false negative, and only 7 of 219 MGIT signal-negative cultures (3.2%) were false positive. The MAC-ELISA is a low-cost, rapid, sensitive, and specific test for MAC in liquid cultures. It could be used in conjunction with or independent of automated culture reading instrumentation. For maximal accuracy and subspecies-specific identification, use of a confirmatory multiplex MAC PCR is recommended.

scholarly journals Validation of the method of quantitative determination of florphenicol in muscle samples by the method of immuno-enzyme analysis

2020 ◽  
pp. 40-45
Author(s):  
M. V. Kostyuk ◽  
◽  
K. S. Myagka ◽  
G. S. Kochetova ◽  
◽  
...  
Keyword(s):  
Immunosorbent Assay ◽  
Screening Method ◽  
Enzyme Analysis ◽  
Enzyme Linked Immunosorbent Assay ◽  
Laboratory Diagnostics ◽  
Screening Methods ◽  
Detection Ability ◽  
Wide Range ◽  
Control Samples

Introduction. Amphenicols are a group of chemical compounds with antibacterial activity, including chloramphenicol (HAF), thiamphenicol (TAF), florfenicol (FF) and their derivatives. Florfenicol (FF) is a synthetic antimicrobial agent with a broad spectrum of action and is one of the most commonly used drugs in poultry, and was developed specifically for veterinary medicine. Given the wide range of activity of florfenicol, the high therapeutic effect combined with low toxicity makes it important for use in animal husbandry. The known method of enzyme-linked immunosorbent assay (ELISA) differs favorably from other screening methods by high sensitivity, specificity, simplicity and speed of performance, availability and stability of reagents, the ability to computer processing of measurement results and automation of test steps, which provides high test efficiency. The aim of the work. To validate the method of enzyme-linked immunosorbent assay to determine the residues of florfenicol in the samples of months of different species of animals (cattle, pigs, chickens, geese, turkeys, rabbits) and fish. Materials and methods. The research was conducted on the basis of the State Research Institute for Laboratory Diagnostics and Veterinary Sanitary Expertise. The material for the study was a solution of florfenicol with a concentration of 1 mg/liter. Results of research and discussion. It was found that the highest value (highest response) for control samples is 0.24 μg/kg and the lowest value for enriched samples (lowest response) - 3.62 μg/kg. According to the obtained results, none of the answers for the enriched samples coincides with the range of answers for the control samples. It follows that the detection ability (CCβ) for this screening method reduces or decreases 5.0 μg/kg The cut-off rate of this test is 3.62 μg/kg. Conclusions and prospects for further research. Validation characteristics have been established for the determination of florfenicol residues in muscle samples, such as: detection ability (CCβ) is 5.0 μg/kg, cut-off level is 3.62 μg/kg. The lowest content of florfenicol that can be determined is 0.2 μg/kg. The percentage of return for enriched samples of both groups is 93 %, which corresponds to the specified production.

Determination of Aflatoxin Concentrations in Peanut Butter by Enzyme-Linked Immunosorbent Assay (ELISA): Study of Three Commercial ELISA Kits

1989 ◽  
Vol 72 (6) ◽  
pp. 965-969
Author(s):  
Alan L Patey ◽  
Matthew Sharman ◽  
Roger Wood ◽  
John Gilbert
Keyword(s):  
United Kingdom ◽  
Liquid Chromatography ◽  
Immunosorbent Assay ◽  
Peanut Butter ◽  
Statistical Treatment ◽  
Enzyme Linked Immunosorbent Assay ◽  
Analytical Laboratories

Abstract Sixteen United Kingdom analytical laboratories participated in an evaluation of 3 commercially available enzyme-linked immunosorbent assay (ELISA) kits for analysis of aflatoxin in peanut butter. Each laboratory was sent 3 sets of 10 randomly numbered samples of peanut butter. Each set consisted of 5 pairs of undisclosed duplicates. Four of the sets of duplicates were naturally contaminated butters with “target” aflatoxin values (estimated by liquid chromatography) between 8 and 81 fig/kg. The fifth pair was a blank peanut butter containing approximately 3 fig/kg of total aflatoxins. A statistical treatment of the results of the study is presented, together with discussion of the relative merits of the different kits.

An Enzyme-Linked Immunosorbent Assay for the Detection of Aspergillus parasiticus and Aspergillus flavus

1997 ◽  
Vol 60 (8) ◽  
pp. 978-984 ◽  
Author(s):  
GUO-JANE TSAI ◽  
SHOU-CHIN YU
Keyword(s):  
Aspergillus Flavus ◽  
Immunosorbent Assay ◽  
False Positive ◽  
Aspergillus Parasiticus ◽  
False Negative ◽  
Zealand White Rabbit ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Molecular Weights ◽  
Sds Page

An enzyme-linked immunosorbent assay (ELISA) was established for the specific detection of Aspergillus parasiticus and Aspergillus flavus. A New Zealand white rabbit was immunized intravenously with 100 μg of A. parasiticus CCRC 30117 mycelial protein extracts. The antibodies were separated and purified. The optimal concentration of the antibody and antibody-peroxidase conjugate used in the established ELISA was 10 μg/ml with a detection limit of 1 μg/ml. Among the 126 strains tested (including 21 strains of A. parasiticus, 11 strains of A. flavus, 34 isolates of A. parasiticus/A. flavus from cereals, and 60 strains of non-A. parasiticus/A. flavus fungi), the false-negative and false-positive rates were 1.5 and 3.3%, respectively. Strains of Aspergillus flavofrucatis and Aspergillus sojae produced false-positive reactions. However, their antigens had much lower cross-reactivity with the antibodies raised against A. parasiticus, as shown from I50 values. The molecular weights of the main antigens of A. parasiticus were 94, 82, and 40 kDa. The two heavier antigens had higher sugar contents, as demonstrated by SDS-PAGE and immunoblotting. A good correlation (r = 0.97) was found between mycelium measurement by weighing and by ELISA for A. parasiticus grown in yeast extract sucrose broth (YESB) at 25°C.

Enzyme-Linked Immunosorbent Assay for Detection of Zearalenone in Corn, Wheat, and Pig Feed: Collaborative Study

1994 ◽  
Vol 77 (6) ◽  
pp. 1500-1508 ◽  
Author(s):  
Glenn A Bennett ◽  
Terry C Nelsen ◽  
Brjnton M Miller
Keyword(s):  
Immunosorbent Assay ◽  
Collaborative Study ◽  
Screening Method ◽  
The United States ◽  
False Positives ◽  
Enzyme Linked Immunosorbent Assay ◽  
Elisa Method ◽  
False Negatives ◽  
Relative Standard ◽  
Pig Feed

Abstract A direct competitive enzyme-linked immunosorbent assay (ELISA) screening method for zearalenone in corn, wheat, and feed at 500 ng/g was evaluated by 23 collaborators (22 laboratories) in an international collaborative study. Eighteen samples of spiked or naturally contaminated corn, wheat, and pig feed were prepared by the sponsoring laboratory and sent for testing with complete test kits to participating collaborators in Canada, Italy, Sweden, The Netherlands, and the United States. Test samples were extracted with methanolwater solution (70 + 30) by shaking on a wrist-action shaker for 3 min. A portion of the extract was mixed with an equal volume of zearalenone-enzyme conjugate, and the mixture was incubated with zearalenone-specific monoclonal antibodies coated onto microtiter wells. All test samples were assayed in duplicate. One of 52 (2%) blanks was reported positive. Thirty-nine of the 52 (75%) samples that were spiked at 500 ng/g were reported as positive. Forty-nine of the 51 (96%) samples with concentrations at or above 1000 ng/g were reported as positive. The overall incidence of false negatives was 6.0% and the incidence of false positives was 22.7% by the ELISA method. Only one (3.4%) false negative was reported for samples containing ≥800 ng/g. In the spectrophotometric method, 8 collaborators determined approximate levels of zearalenone in test samples from standard curves constructed from spiked extracts (0–3000 ng/g of each commodity tested). This method gave and overall incidence of false negatives of 5.7% and false positives of 17.8%. Average relative standard deviations, RSDr (repeatability) and RSDR (reproducibility), were 11.6 and 25.1% for spiked samples and 11.7 and 33.1% for naturally contaminated samples, respectively. Standard curves were constructed with each set of samples assayed. Comparison of absorbance values from these standard curves indicate the performance of reagents and antibody used in the assay. The ELISA method has been adopted first action by AOAC INTERNATIONAL as a screening method for zearalenone at ≥800 ng/g in corn, wheat, and pig feed.

Determination of permethrin in indoor air by liquid chromatography with enzyme linked immunosorbent assay

1999 ◽  
Vol 393 (1-3) ◽  
pp. 103-108 ◽  
Author(s):  
S Oepkemeier ◽  
S Schreiber ◽  
D Breuer ◽  
G Key ◽  
W Kleiböhmer
Keyword(s):  
Liquid Chromatography ◽  
Immunosorbent Assay ◽  
Indoor Air ◽  
Enzyme Linked Immunosorbent Assay
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