Comparison of Colorimetric Monoclonal Enzyme Immunoassay Screening Methods for Detection of Salmonella in Foods

1990 ◽  
Vol 73 (1) ◽  
pp. 43-50
Author(s):  
Michael S Curiale ◽  
Mary Joan Klatt ◽  
Barbara J Robison ◽  
Lisa T Beck
Keyword(s):  
Enzyme Immunoassay ◽  
Magnetic Beads ◽  
False Negative ◽  
Screening Method ◽  
False Negative Rate ◽  
Culture Method ◽  
Food Samples ◽  
Assay Method ◽  
Screening Methods ◽  
Well Assay

Abstract A colorimetric enzyme immunoassay (EIA) method for detection of Salmonella in foods has been compared to the AOAC colorimetric monoclonal EIA screening method (986.35,15th ed.; 46.B21-46.B29, 14th ed.). The assays use the same monoclonal antibodies and have similar reactivity toward Salmonella. However, the new assay uses antibody-coated microtiter wells instead of coated magnetic beads to capture Salmonella antigens. Compared with the bead assay, the coated-well assay format requires significantly less time to complete, and was consistently able to detect lower levels of Salmonella In mixed culture. Compared to the standard AOAC culture method for food samples, the plate assay was as productive. No false negatives were obtained by the immunoassay; the false negative rate was 1.1% by the culture method. The rate of agreement between the 2 methods was 99.1 %. The official final action bead assay method for Salmonella in foods, 986.35, and the same assay for use with low-moisture foods, 987.11, have been modified official first action to use antibody-coated microtiter strip-wells

Comparison between VIDAS Automatic Enzyme-Linked Fluorescent Immunoassay and Culture Method for Salmonella Recovery from Pork Carcass Sponge Samples

2002 ◽  
Vol 65 (10) ◽  
pp. 1656-1659 ◽  
Author(s):  
KUANG-SHENG YEH ◽  
CHIN-EN TSAI ◽  
SHIH-PING CHEN ◽  
CHAO-WEI LIAO
Keyword(s):  
False Negative ◽  
Screening Method ◽  
Culture Method ◽  
Automated System ◽  
Rapid Screening ◽  
Assay Method ◽  
Intensive Culture ◽  
Negative Results ◽  
False Negative Results ◽  
Potential Alternative

VIDAS Salmonella (VIDAS-SLM) is an automated system that uses the enzyme-linked fluorescent assay method to detect Salmonella species. This study evaluated the efficacy of the VIDAS-SLM method in detecting Salmonella species in pork carcass sponge samples gathered from 10 slaughter plants in Taiwan. Two hundred fifty-seven pork carcass sponge samples were screened by the VIDAS-SLM method and by the culture method in parallel. While 18 sponge samples were found to test positive by both methods, the VIDAS-SLM method detected four additional positive samples for which the culture method failed to recover Salmonella. The specificity of the VIDAS-SLM method was found to be 0.98, and its sensitivity was 1.0, since no false-negative results occurred. Artificially inoculated Salmonella at concentrations as low as 5.0 × 100 CFU/ml was detected in the heat-inactivated sponge sample in the presence or absence of 5.0 × 104 CFU of Citrobacter freundii per ml. Thus, the VIDAS-SLM method is a rapid screening method and a potential alternative to the time- and labor-intensive culture method.

Improved Hydrophobic Grid Membrane Filter Method, Using EF-18 Agar, for Detection of Salmonella in Foods: Collaborative Study

1990 ◽  
Vol 73 (5) ◽  
pp. 734-742
Author(s):  
Phyllis Entis
Keyword(s):  
Membrane Filter ◽  
Collaborative Study ◽  
False Negative ◽  
Screening Method ◽  
Culture Method ◽  
Soy Flour ◽  
Poultry Meat ◽  
Filter Method ◽  
Negative Results ◽  
False Negative Results

Abstract A collaborative study was carried out in 30 laboratories to validate Improvements to the official final action hydrophobic grid membrane filter (HGMF) screening method for Salmonella in foods, 985.42, by comparing the performance of the improved HGMF method against that of the AOAC/BAM conventional culture method. Six products were Included In the collaborative study: milk chocolate, raw deboned poultry meat, black pepper, soy flour, egg yolk powder, and nonfat dry milk. The raw deboned poultry meat was naturally contaminated with Salmonella, and the remaining 5 products were each Inoculated In advance with low levels of Individual Salmonella serotypes. The AOAC/BAM method produced 11 false negative results and the Improved HGMF method produced 18 false negative results. The improved HGMF Salmonella method has been approved Interim official first action for all foods to replace the HGMF official final action method, 985.42.

Diagnostic value of cytokeratin-1, survivin and TG expression in circulating tumor cells in the differentiation of benign and malignant thyroid nodules.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e17575-e17575
Author(s):  
Jie Liu ◽  
Siyuan Xu ◽  
Jinghua Luo ◽  
Yan Wang ◽  
Xia Liu ◽  
...  
Keyword(s):  
Thyroid Cancer ◽  
Real Time ◽  
Quantitative Pcr ◽  
Thyroid Nodules ◽  
False Negative ◽  
False Negative Rate ◽  
Diagnostic Value ◽  
Screening Methods ◽  
Real Time Quantitative Pcr ◽  
Minimal Trauma

e17575 Background: Fine needle aspiration cytology (FNAB) has the advantages of minimal trauma, speed and accuracy, and is currently considered to be the most predictive screening technique before thyroid nodule surgery. However, there are several drawbacks to this method, including certain complications, a relatively high false negative rate, a low acceptance of invasive surgery among patients, and the fact that about 20% of the lesions cannot be clearly defined as benign or malignant. Blood-based noninvasive testing can be used to analyze circulating cancer cells (CTCs) for clinical testing. Here, we investigated the performance of CTCs in thyroid cancer screening. Methods: We established a multi-marker real-time quantitative PCR (CK-19/surviving/Tg) to detect and quantify CTCs in peripheral blood samples. 100 subjects who were diagnosed by ultrasound imaging as having thyroid nodules were enrolled. FNAB or surgical specimens were subjected to pathological tests to differentiate between the benign nodules and thyroid cancer. Meanwhile the CTCs in the blood were isolated and quantified by multi-marker qPCR. Results: Among 100 patients, 50 were diagnosed as Papillary Thyroid Carcinoma (PTC) by pathological test. The sensitivity of each single marker of CK19, Survivin and Tg were only 48%, 44%, and 50% respectively, with the specificity of 94%, 100% and 94%. However, the combination of these three markers results in the highest sensitivity and specificity of 86% and 90%. Thus, the combined marker could achieve the best diagnostic value. Conclusions: Compared with FNAB, CTC is minimally invasive. The performance of the multi-marker real-time quantitative PCR showed that CTC could be used as an adjunctive test after ultrasound evaluation. Our results indicated that CTCs have potential clinical value in the identification of benign and malignant thyroid nodules.

Performance criteria for rapid screening methods to detect mycotoxins

2014 ◽  
Vol 7 (4) ◽  
pp. 439-447 ◽  
Author(s):  
C. von Holst ◽  
J. Stroka
Keyword(s):  
False Negative ◽  
Screening Method ◽  
Performance Criterion ◽  
Performance Criteria ◽  
Rapid Screening ◽  
Cost Ratio ◽  
Screening Methods ◽  
Method Performance ◽  
Official Control ◽  
The Impact

The paper describes the validation of screening methods that are used for official control to classify samples into negative and suspect positive samples. The concept is based on the principle that negative samples are considered as compliant, whereas suspect positive samples need to be re-analysed with confirmatory methods. An important performance criterion often used is a maximum value of 5% for the probability of false negative results obtained on samples that contain the analyte at the legal limit. Since the result of analysis is a binary decision, specific validation schemes need to be applied. The paper places emphasis on practical aspects of the calculation of the method performance characteristics, which are required to check whether the methods fulfil the performance criterion. The paper shows that screening methods based on a visual inspection, e.g. a dipstick, require special data treatment. In contrast there are many methods where the classification into negative and suspect positive samples is based on the comparison of a measured response against a cut-off value. This type of methods can be validated with quantitative statistics. The paper also elaborates on the calculation of the rate of false positive results of compliant samples. In addition the impact on the economical aspect of the use of the screening method is estimated, taking into account external factors such as the cost ratio between the screening and the confirmatory method and the occurrence of non-compliant samples in the entire population of the samples.

Comparison of the BAX System PCR Method to Brazil's Official Method for the Detection of Salmonella in Food, Water, and Environmental Samples

2008 ◽  
Vol 71 (12) ◽  
pp. 2442-2447 ◽  
Author(s):  
INGRID BOESCHE TOMAZELLI ◽  
JOSINETE BARROS de FREITAS ◽  
LEANIA MARIA FABBI ◽  
TEREZINHA AGNESE FILIPINI ◽  
CLÁUDIA MARIA da SILVA ◽  
...  
Keyword(s):  
Environmental Samples ◽  
Limit Of Detection ◽  
False Positive Rate ◽  
False Negative ◽  
False Negative Rate ◽  
Reference Method ◽  
Culture Method ◽  
Official Method ◽  
Positive Rate ◽  
Pcr Method

A two-stage study compared the BAX system PCR method with the reference culture method used by the Brazilian Ministry of Agriculture and Food Supply for the detection of Salmonella in food, water, and environmental samples. In stage 1, fish matrix samples (n = 258) were spiked at several levels with Salmonella and a combination of Salmonella and non-Salmonella competitive organisms. Replicates were analyzed by the BAX system PCR method and the reference method with comparable results (sensitivity ≥ 97.5%, specificity ≥ 83.3%) from both methods at the limit of detection. In stage 2, a total of 1,988 samples with 70 product types were analyzed with both methods. Five laboratories were involved in this study, and the samples used were from routine analyses. The BAX system PCR method was shown to be comparable to the reference method, with a limit of detection of 1.0 to 2.0 CFU/25 g of sample. Analysis of the results obtained in stage 2 and in the combination of stages 1 and 2 for the BAX system showed the following performance: sensitivity ≥ 99.0%, specificity ≥ 97.2%, false-negative rate ≤ 1.1%, and false-positive rate ≤ 2.8%. Therefore, the BAX system appears to be equivalent to the reference method, with ≥ 97.3% agreement.

Comparison of Salmonella Bio-EnzaBead Immunoassay Method and Conventional Culture Procedure for Detection of Salmonella in Foods

1987 ◽  
Vol 50 (5) ◽  
pp. 379-385 ◽  
Author(s):  
KARL F. ECKNER ◽  
RUSSELL S. FLOWERS ◽  
BARBARA J. ROBISON ◽  
JEROME A. MATTINGLY ◽  
DAMIEN A. GABIS ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Enzyme Immunoassay ◽  
Culture Method ◽  
Food Samples ◽  
Selective Enrichment ◽  
Conventional Culture ◽  
Significant Difference ◽  
Standard Culture ◽  
Raw Shrimp ◽  
Culture Procedure

A rapid enzyme immunoassay screening procedure (EIA) utilizing two monoclonal antibodies specific for salmonellac was compared to the standard culture method (BAM/AOAC) on 1,289 samples representing 26 food types. The samples consisted of 760 artificially inoculated, 150 naturally contaminated, and 379 uninoculated food samples. There were 594 samples positive by the EIA (optical densities greater than 0.2 at 405 nm), of which 568 were confirmed culturally from M-broth. A total of 570 samples was positive by the BAM/AOAC procedure. Of the foods tested, there was no significant difference between the two methods, with the exception of cake mix and raw shrimp. The EIA was significantly better for detecting Salmonella in cake mix, while the culture procedure was more productive for shrimp. The method employed a 24 ± 2-h preen-richment, an 18-h selective enrichment, and a 6-h M-broth post-enrichment. The EIA assay required an additional 2 h for a total of 48 h, compared to a minimum of 4 d by BAM/AOAC.

Polyclonal Enzyme Immunoassay Method for Detection of Motile and Non-Motile Salmonella in Foods: Collaborative Study

1992 ◽  
Vol 75 (6) ◽  
pp. 1032-1044 ◽  
Author(s):  
Philip T Feldsine ◽  
Maria T Falbo-Nelson ◽  
David L Hustead
Keyword(s):  
Enzyme Immunoassay ◽  
Polyclonal Antibodies ◽  
Collaborative Study ◽  
False Negative ◽  
Culture Method ◽  
Black Pepper ◽  
Soy Flour ◽  
Agreement Rate ◽  
Dry Milk ◽  
Antibody Reaction

Abstract A new enzyme immunoassay (EIA) method for detection of motile and non-motile Salmonella was examined in a multilaboratory collaborative study. This method uses a proprietary formulation of polyclonal antibodies to Salmonella and is controlled to maintain specificity. Sensitivity is enhanced with an additional antibody reaction designed to minimize false-negative reactions attributable to steric interference that can occur during conjugate binding in immunoassay procedures. Thirty-two laboratories participated in this evaluation, which included 6 food types: nonfat dry milk, dry egg, black pepper, soy flour, chocolate, and ground poultry. Of the 1020 samples analyzed, there was a 97.2% agreement rate between the EIA method and the AOAC/Bacteriological Analytical Manual(BAM) culture method, 967.26. False-negative rates for the 2 methods were comparable for all foods and all Salmonella levels except ground poultry, where the EIA method detected significantly more confirmed positive samples than did the AOAC/BAM method. Nineteen samples were positive by EIA but negative by the culture method, and 10 samples were negative by EIA but positive by the culture method

Efficiency of Two Commercial ELISA Kits Compared with the BAM Culture Method for Detecting Listeria in Naturally Contaminated Foods

1991 ◽  
Vol 74 (5) ◽  
pp. 819-821 ◽  
Author(s):  
Charles W Noah ◽  
Nora C Ramos ◽  
Virginia M Gipson
Keyword(s):  
Culture Method ◽  
Elisa Test ◽  
Food Samples ◽  
Alternative Methods ◽  
Rapid Screening ◽  
Enzyme Linked Immunosorbent Assay ◽  
Screening Methods ◽  
Test Results ◽  
Enrichment Broth ◽  
University Of Vermont

Abstract The efficiency of 2 commercial enzyme-linked Immunosorbent assay (ELISA) kite (Listeria-Tek™ and Tecra™) for detecting Listeria in naturally contaminated foods was evaluated and compared with that of the culture method described in the Bacteriological Analytical Manual (BAM). Both ELISAs use modified University of Vermont (UVM-1) medium as a primary enrichment; the BAM method uses Listeria enrichment broth. Secondary enrichments for Llsterla-Tek and Tecra, respectively, were Fraser broth and UVM-2, which contains additional acriflavln-HCI. When ELISA test results differed, secondary enrichments were tested against the other ELISA; Fraser broth was used to determine recovery rates because of Its superiority over UVM-2. Of the 178 food samples examined, the presence of Listeria was detected and culturally confirmed in 38, 37, and 40 samples by the BAM, Llsterla- Tek, and Tecra methods, respectively. Differences in results of the EUSAs compared with those of the BAM method were not statistically significant; however, differences between results of the 2 ELISA methods were significant. It was concluded that as rapid screening methods, the Llsteria-Tek and the Tecra kits qualify as alternative methods to the BAM cultural method.

scholarly journals Evaluation of an adenosine 5'-triphosphate assay as a screening method to detect significant bacteriuria

1976 ◽  
Vol 3 (1) ◽  
pp. 42-46
Author(s):  
D N Alexander ◽  
G M Ederer ◽  
J M Matsen
Keyword(s):  
False Negative ◽  
Screening Method ◽  
Culture Method ◽  
Clinical Microbiology Laboratory ◽  
University Of Minnesota ◽  
Atp Assay ◽  
Negative Results ◽  
False Negative Results ◽  
Significant Bacteriuria ◽  
Urine Specimens

The bioluminescent reaction of adenosine 5'-triphosphate (ATP) with luciferin and luciferase has been used in conjunction with a sensitive photometer (Lab-Line's ATP photometer) to detect significant bacteriuria in urine. This rapid method of screening urine specimens for bacteriuria was evaluated by using 348 urine specimens submitted to the clinical microbiology laboratory at the University of Minnesota Hospitals for routine culture using the calibrated loop-streak plate method. There was 89.4% agreement between the culture method and the ATP assay, with 7.0% false positive and 27.0% false negative results from the ATP assay using 10(5) organisms/ml of urine or greater as positive for significant bacteriuria and less than 10(5) organisms/ml as negative for significant bacteriuria.

Effect of non-fat dry milk on recovery of staphylococcal thermonuclease from foods

1979 ◽  
Vol 25 (1) ◽  
pp. 44-46 ◽  
Author(s):  
C. E. Park ◽  
H. B. El Derea ◽  
M. K. Rayman
Keyword(s):  
False Negative ◽  
Ground Beef ◽  
Acid Precipitation ◽  
Food Samples ◽  
Assay Method ◽  
Negative Results ◽  
False Negative Results ◽  
Dry Milk ◽  
Egg Products ◽  
Subsequent Acid

Modification of the method of Tatini et al. (1976) by addition of non-fat dry milk (NFDM) to food samples and subsequent acid precipitation at pH 3.8 enhanced the recovery of staphylococcal thermonuclease (TNase) from most of 37 foods tested. The modified TNase assay method allowed detection of 10 ng (0.002 units) of the enzyme per gram of each of the following foods: ground beef, boiled egg products, whey powder, fruit-containing yogurt, dressings and spreads, potato and egg salads, and pastas, all of which gave false-negative results without NFDM.

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