Rapid screening methods for beta-emitters in food samples

2015 ◽  
Vol 141 ◽  
pp. 130-137 ◽  
Author(s):  
A. Vos van Avezathe ◽  
P.N. Brandhoff ◽  
M.J. van Bourgondiën ◽  
G.C. Krijger
Keyword(s):  
Food Samples ◽  
Rapid Screening ◽  
Screening Methods ◽  
Beta Emitters

scholarly journals Comparison of Visual Immunoassay and Chromogenic Culture Medium for the Presence of Listeria spp. in Foods

2002 ◽  
Vol 85 (5) ◽  
pp. 1201-1204 ◽  
Author(s):  
Philip Istafanos ◽  
Lawrence James
Keyword(s):  
Culture Medium ◽  
Food Samples ◽  
Screening Tools ◽  
Rapid Screening ◽  
Screening Methods ◽  
Visual Test ◽  
Test Results ◽  
Early Screening ◽  
Agar Method ◽  
Excellent Tool

Abstract Two rapid screening methods [the TECRA™ Listeria Visual Immunoassay (LIS–VIS) kit, an AOAC-approved 48 h visual test, which detects Listeria through colorimetry, and BCM™ Listeria isolation and differentiation plating agar] were used to screen U.S. Food and Drug Administration-regulated commodities for the presence of Listeria spp. Seventy-four different food samples were screened for the presence of Listeria spp. by using both protocols. Test results for the TECRA LIS–VIA showed 66 negative samples and 1 false positive, with 4 confirmed as L. monocytogenes and 3 as L. innocua. With the BCM agar, 67 samples were negative, 4 were confirmed as L. monocytogenes, and 3 were confirmed as L. innocua. Both methods showed similar results and were effective screening tools for Listeria spp. in foods. The BCM agar method proved to be a rapid, sensitive, and excellent tool for early screening and differentiation of Listeria spp. present in foods.

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 Rapid Screening for Salmonella in Raw Pet Food by Loop-Mediated Isothermal Amplification

2020 ◽  
Author(s):  
Kelly J. Domesle ◽  
Shenia R. Young ◽  
Beilei Ge
Keyword(s):  
Foodborne Pathogens ◽  
Food Samples ◽  
Isothermal Amplification ◽  
Rapid Screening ◽  
Screening Methods ◽  
Lamp Method ◽  
Pet Food ◽  
Loop Mediated Isothermal Amplification ◽  
Freeze Dried ◽  
Antimicrobial Resistance Genes

Raw pet food, comprised of raw meat and vegetables, has increased in popularity in recent years. Multiple surveys and frequent recalls indicate that this commodity has a high risk of contamination with Salmonella and other foodborne pathogens. Improved screening methods are needed to meet the growing demand for testing. This matrix verification study aimed to apply a Salmonella loop-mediated isothermal amplification (LAMP) method, recently completed multi-laboratory validation in dry dog food, in several raw pet food matrices, following the U.S. Food and Drug Administration’s method validation guidelines. Five types of raw pet food, consisting of freeze-dried beef and chicken treats, and frozen beef, pork, and turkey complete foods, were evaluated. For each matrix, two sets of ten 25-g test portions (seven inoculated with ≤ 30 cells of Salmonella Typhimurium and three uninoculated controls) were examined. One set was preenriched in buffered peptone water and the other one in lactose broth, which was followed by LAMP screening using two isothermal master mixes (ISO-001 and ISO-004). All results were confirmed by culture as specified in the Bacteriological Analytical Manual (BAM). The LAMP method accurately detected Salmonella in all inoculated test portions of the five raw pet food samples, regardless of the preenrichment broth used. Positive results could be obtained within 4 min of the LAMP run using the LAMP ISO-004 master mix. All uninoculated controls tested negative by LAMP or BAM. Additionally, one turkey-based complete pet food sample was found to be already contaminated with three Salmonella serovars harboring multiple antimicrobial resistance genes. The Salmonella LAMP method offers a rapid, reliable, and robust tool for routine screening of Salmonella in raw pet food, which will help better ensure product safety and protect public health.

Rapid Screening Methods for Bleeding Disorders. A Three Year Survey

1964 ◽  
Vol 11 (02) ◽  
pp. 506-512 ◽  
Author(s):  
V. A Lovric ◽  
J Margolis
Keyword(s):  
Laboratory Tests ◽  
Capillary Blood ◽  
Screening Tests ◽  
Rapid Screening ◽  
Screening Methods ◽  
Bleeding Disorders ◽  
Routine Laboratory ◽  
Clotting Time ◽  
Kaolin Clotting Time ◽  
In Infants And Children

SummaryAn adaptation of “kaolin clotting time” and prothrombin time for use on haemolysed capillary blood provided simple and sensitive screening tests suitable for use in infants and children. A survey of three year’s experience shows that these are reliable routine laboratory tests for detection of latent coagulation disorders.

Development of New Geopolymer-Based System for Challenging Well Conditions

2021 ◽  
Author(s):  
Siti Humairah Abd Rahman ◽  
Anatoly Medvedev ◽  
Andrey Yakovlev ◽  
Yon Azwa Sazali ◽  
Bipin Jain ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Construction Industry ◽  
Raw Materials ◽  
Critical Role ◽  
Acid Resistance ◽  
Oil Industry ◽  
Rapid Screening ◽  
Fluid Loss ◽  
Screening Methods

Abstract With the development of new oil formations and with the advent of new directions in the global energy sector, new requirements for materials for well construction appear. With the close attention to environmental footprint and unique properties, one of the promising materials for well cementing is geopolymers. Being a relatively new material, they are characterized by low carbon footprint, high acid resistance and attractive mechanical properties. This article is aimed at developing new geopolymer slurries for the oil industry, their characterization and field implementation analysis. With the ultimate goal of developing a methodology for the analysis of raw materials and designing the geopolymer slurries, studies were carried out on various raw materials, including different types of fly ash. Based on the data obtained and rapid screening methods, an approach was developed to formulate a geopolymer composition recipe. Since not all cement additives directly work in geopolymers, special attention was paid to control the thickening time and fluid loss. The methods of XRD, XRF, ICP-MS, density, particle size distribution measurements as well as API methods of cement testing were used to understand the composition and structure of the materials obtained, their properties and design limitations. A special approach was applied to study the acid resistance of the materials obtained and to compare with conventional cements and slags. Using one of the most common sources of aluminosilicate, fly ash, formulations with a density of 13.5 – 16.5 lbm/galUS were tested. A sensitivity analysis showed that the type of activator and its composition play a critical role both in the mechanical properties of the final product and in the solidification time and rheological properties of the product. The use of several samples of fly ash, significantly different in composition, made it possible to formulate the basic rules for the design of geopolymers for the oil industry. An analysis was also carried out on 10 different agents for filtration and 7 moderators to find a working formulation for the temperature range up to 100°C. The samples were systematically examined for changes in composition, strength, and acid resistance was previously measured. Despite the emergence of examples of the use of geopolymers in the construction industry and examples of laboratory testing of geopolymers for the oil industry, to the best of our knowledge, there has been no evidence of pumping geopolymers into a well. Our work is an attempt to develop an adaptation of the construction industry knowledge to the unique high pressure, high temperature conditions of the oil and gas industry. The ambitions of this work go far beyond the laboratory tests and involve yard test experiments.

scholarly journals Widespread QoI Fungicide Resistance Revealed Among Corynespora cassiicola Tomato Isolates in Florida

Plant Disease ◽  
2020 ◽  
Vol 104 (3) ◽  
pp. 893-903 ◽  
Author(s):  
Keevan J. MacKenzie ◽  
Katia V. Xavier ◽  
Aimin Wen ◽  
Sujan Timilsina ◽  
Heather M. Adkison ◽  
...  
Keyword(s):  
Amino Acid Position ◽  
Rapid Screening ◽  
Silent Mutation ◽  
Screening Methods ◽  
Corynespora Cassiicola ◽  
Qoi Fungicides ◽  
Quinone Outside Inhibitor ◽  
Target Spot ◽  
Moderately Resistant ◽  
Qoi Resistance

Target spot of tomato caused by Corynespora cassiicola is one of the most economically destructive diseases of tomato in Florida. A collection of 123 isolates from eight counties in Florida were evaluated for sensitivity to azoxystrobin and fenamidone based on mycelial growth inhibition (MGI), spore germination (SG), detached leaflet assays (DLAs), and sequence-based analysis of the cytochrome b gene (cytb). Cleavage of cytb by restriction enzyme (Fnu4HI) revealed the presence of a mutation conferring a glycine (G) to alanine (A) mutation at amino acid position 143 (G143A) in approximately 90% of the population, correlating with quinone outside inhibitor (QoI) resistance based on MGI (<40% at 5 μg/ml), SG (<50% at 1 and 10 μg/ml), and DLA (<10% severity reduction). The mutation conferring a phenylalanine (F) to leucine (L) substitution at position 129 (F129L) was confirmed in moderately resistant isolates (#9, #19, and #74) based on MGI (40 to 50% at 5 μg/ml), SG (<50% at 1 μg/ml and >50% at 10 μg/ml), and DLA (>10% and <43% severity reduction) for both QoI fungicides, whereas sensitive isolates (#1, #4, #7, #28, #29, #46, #61, #74, #75, #76, #91, #95, and #118) based on MGI (>50% at 5 μg/ml), SG (>50% at 1 μg/ml and 10 μg/ml), and DLA (>50% severity reduction) correlated to non-mutation-containing isolates or those with a silent mutation. This study indicates that QoI resistance among C. cassiicola isolates from tomato is widespread in Florida and validates rapid screening methods using MGI or molecular assays to identify resistant isolates in future studies.

A Rapid Test to Detect ST-producing Escherichia coli in Food

1992 ◽  
Vol 55 (10) ◽  
pp. 792-795
Author(s):  
KARSTEN FEHLHABER ◽  
RÜDIGER-THOMAS HESELER
Keyword(s):  
Escherichia Coli ◽  
Test Procedure ◽  
Brain Heart Infusion ◽  
Rapid Test ◽  
Food Samples ◽  
Food Sample ◽  
Rapid Screening ◽  
Infant Mouse ◽  
E Coli ◽  
Rapid Screening Test

Pasteurized milk, liquid egg, minced meat, and various salads were artificially contaminated with varying numbers of cells from six Escherichia coli (E. coli) strains able to produce heat-stable enterotoxins (ST). The ST-producing E. coli were detected by the following procedure within 24 h without isolation by cultivation. After enrichment of the food sample in GN broth (4 h at 37°C), the material was transferred to brain heart infusion broth, incubated (16–18 h at 37°C), centrifuged (20 min, 7000 g) and heated to 80°C for 10 min, the supernatant was tested with the infant mouse test. The sensitivity (= ratio of detectable E. coli per total microbial numbers in the food sample) of the test procedure was high even in many food samples with a considerable competitive microbial flora. The procedure was used to test 419 routine food samples. Enterotoxigenic bacteria were found in 7 samples of liquid egg and 4 samples of salad. The test is recommended as a rapid screening test in food control.

scholarly journals Detection of Exon Deletions within an Entire Gene (CFTR) by Relative Quantification on the LightCycler

2006 ◽  
Vol 52 (11) ◽  
pp. 2005-2012 ◽  
Author(s):  
Mircea Schneider ◽  
Franziska Joncourt ◽  
Javier Sanz ◽  
Thomas von Känel ◽  
Sabina Gallati
Keyword(s):  
Gene Dosage ◽  
Large Deletion ◽  
Rapid Screening ◽  
Cftr Gene ◽  
Screening Methods ◽  
Sequence Variant ◽  
Β2 Microglobulin ◽  
Large Deletions ◽  
Specific Deletion ◽  
Entire Gene

Abstract Background: Cystic fibrosis (CF) is associated with at least 1 pathogen point sequence variant on each CFTR allele. Some symptomatic patients, however, have only 1 detectable pathogen sequence variant and carry, on the other allele, a large deletion that is not detected by conventional screening methods. Methods: For relative quantitative real-time PCR detection of large deletions in the CFTR gene, we designed DNA-specific primers for each exon of the gene and primers for a reference gene (β2-microglobulin). For PCR we used a LightCycler system (Roche) and calculated the gene-dosage ratio of CFTR to β2-microglobulin. We tested the method by screening all 27 exons in 3 healthy individuals and 2 patients with only 1 pathogen sequence variant. We then performed specific deletion screenings in 10 CF patients with known large deletions and a blinded analysis in which we screened 24 individuals for large deletions by testing 8 of 27 exons. Results: None of the ratios for control samples were false positive (for deletions or duplications); moreover, for all samples from patients with known large deletions, the calculated ratios for deleted exons were close to 0.5. In addition, the results from the blinded analysis demonstrated that our method can also be used for the screening of single individuals. Conclusions: The LightCycler assay allows reliable and rapid screening for large deletions in the CFTR gene and detects the copy number of all 27 exons.

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