bluuebunny/crossref_metadata_2025_split huggingface dataset:
Method Extension Study to Validate Applicability of AOAC Official Method 996.14 Assurance® Polyclonal Enzyme Immunoassay for Detection of Listeria monocytogenes and Related Listeria spp. from Environmental Surfaces: Collaborative Study
Authors: Feldsine Philip T , Lienau Andrew H , Leung Stephanie C , Mui Linda A ,   Collaborators:, Aharchi J , Aldridge I , Arling V , Bullard C , Carlson P , Cox C , Deiss K , Dillon J , Ellingson J , Fitzgerald S , Forgey R , Gailbreath K , Gallagher D , Geftman V , Herbst K , Hillis P , Johnson M , Koch S , Lewis D , Luepke J , McDonagh S , McGovern B , Moon B , Moreland L , Murray L , Richter D , Rucker C , Siu M-C , Smith C , Smith J , Stoltzfus E , Summers C , Taylor B , Toth J , White S , Witt J-L , Young S 
Published: February 2020

Abstract
Test portions from 3 environmental surface types, representative of typical surfaces found in a food production facility, were analyzed by the Assurance®Listeria Polyclonal Enzyme Immunoassay (EIA) and the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) culture method for Listeria monocytogenes and related Listeria species. In all cases, naturally contaminated environmental test samples were collected from an actual food production facility by sponge or swab. Test samples from concrete surfaces were collected by both swab and sponge; sponge test samples were collected from rubber surfaces, and swabs were used to sample steel surfaces. Test portions from each surface type were simultaneously analyzed by both methods. A total of 23 collaborators, representing government agencies, as well as private industry in both the United States and Canada, participated in the study. During this study, a total of 550 test portions and controls was analyzed and confirmed, of which 207 were positive and 336 were negative by both methods. Six test portions were positive by culture, but negative by the EIA. Three test portions were negative by culture, but positive by the EIA. Two test portions were negative by EIA and by culture, but confirmed positive when EIA enrichment broths were subcultured to selective agars. The data reported here indicate that the Assurance®Listeria EIA method and the USDA/FSIS culture method are statistically equivalent for detection of L. monocytogenes and related Listeria species from environmental surfaces taken by sponges or swabs.
Factors Affecting Multiresidue Determination of Priority Herbicides when Using Solid-Phase Microextraction
Authors: Lambropoulou Dimitra A , Konstantinou Ioannis K , Albanis Triantafyllos A 
Published: February 2020

Abstract
A solid-phase microextracton (SPME) procedure was developed for the determination of 10 selected organonitrogen herbicides (s-ethyl dibropylthiocarbamate [EPTC], molinate, propachlor, trifluralin, simazine, atrazine, propazine, terbuthylazine, alachlor, and prometryn) and was tested with various natural waters. Gas chromatography coupled with flame thermionic and mass spectrometric detection was used for quantitation. For this purpose, polydimethylsiloxane and polyacrylate fibers were used and the factors affecting the SPME process such as pH, ionic strength, methanol content, memory effect, stirring rate, and adsorption-time profile were investigated and optimized. By using spiked liquid chromatography water, optimal factors were determined to be 25% salt, &lt;0.5% methanol, stirring rate of 960 rpm, pH 4, and an equilibrium time of 30 min. These conditions were used in further studies of the fibers and in analysis of natural water samples. The method was applied to spiked natural waters such as ground water, sea water, lake water, and river water at a concentration range of 0.5–10 μg/L. Limits of detection ranged from 5 to 90 ng/L, and precision ranged from 5 to 15% (as relative standard deviation), depending on the pesticide, fiber, and detector used. The recoveries of herbicides were 70.2–118.4%, and the average r2 values of the calibration curves were &gt;0.99 for all analytes. The results demonstrate the suitability of the SPME method to determine these organonitrogen herbicides in various natural waters. River water samples originating from the Epirus region (Northwestern Greece) were analyzed to verify the performance of the optimized method by comparing the results obtained by SPME with those obtained by using conventional solid-phase extraction of the selected herbicides.
Detection and Isolation of Listeria monocytogenes from Food Samples: Implications of Sublethal Injury
Authors: Donnelly Catherine W 
Published: February 2020

Abstract
Detection of L. monocytogenes is often limited by the performance of the enrichment media used to support bacterial growth to detectable levels. Because Listeria may exist at extremely low levels in foods, sample enrichment protocols must amplify these low initial populations to detectable limits. Listeria may also exist in an injured state in food products as a result of processing treatments such as heating, freezing, exposure to acids, or exposure to sanitizing compounds. Selective agents in enrichment media normally used for recovery of Listeria may inhibit repair and detection of sublethally injured Listeria, which may go on to repair, grow, and regain pathogenicity. Simple modifications to existing regulatory protocols, such as those that use more than one enrichment broth, raise sensitivity of detection to 90%. This review shows the efficacy of repair/enrichment strategies, which increase sensitivity of detection to 97.5–98.8% compared with 65–70% by standard regulatory protocols. Ribotype analysis of isolates obtained from meat samples reveals a complex microbial ecology, with striking differences in both number and distribution of distinct genetic types of Listeria, depending upon whether samples are enriched in selective or repair/enrichment media. In studies on enrichment of dairy environmental samples in University of Vermont medium and Listeria repair broth (UVM and LRB), combining these 2 primary enrichment media into a single tube of Fraser broth for dual secondary enrichment yielded a significantly higher percentage (p &lt; 0.05) of Listeria-positive samples than did use of either LRB or UVM alone. Refinement of conventional Listeria recovery methods should consider the importance of the enrichment step, the nutritional needs of specific genetic types, and the physiological condition of Listeria isolates in foods.
Polymerase Chain Reaction-Based Methods for Detection of Listeria monocytogenes: Toward Real-Time Screening for Food and Environmental Samples
Authors: Norton Dawn M 
Published: February 2020

Abstract
A review is presented of nucleic acid amplification-based methodology, specifically polymerase chain reaction (PCR)-based assays, for the detection of Listeria monocytogenes in food and environmental samples. Until recently, developmental challenges including poor sensitivity, due in part to reaction inhibition by components of the sample matrix, and the potential for false-positive reactions have limited routine application of PCR-based screening assays. Commercial assays address these challenges while offering convenient, standardized protocols, a high level of automation, and results within 2 days after the sampling date. Although sample enrichment is necessary to achieve desired detection limits, continued efforts toward template purification will facilitate the development of assays offering real-time, quantitative results. The development of ribonucleic acid (RNA) amplification-based assays may increase in importance, particularly if end-product testing is prioritized by regulatory agencies, as messenger RNA appears to serve as an accurate indicator of cell viability. Further, the increase in target copy number may improve assay sensitivity. PCR-based screening methods offer efficient, reliable results and are ideal for monitoring the presence of L. monocytogenes in foods and in the food processing environment.
Molecular Subtyping Methods for Listeria monocytogenes
Authors: Wiedmann Martin 
Published: February 2020

Abstract
Conventional, phenotypic, and DNA-based subtyping methods allow differentiation of Listeria monocytogenes beyond the species and subspecies level. Bacterial subtyping methods not only improve our ability to detect and track human listeriosis outbreaks, but also provide tools to track sources of L. monocytogenes contamination throughout the food system. The use of subtyping methods also provides an opportunity to better understand the population genetics, epidemiology, and ecology of L. monocytogenes. The last 5 years have seen tremendous advancements in the development of sensitive, rapid, automated, and increasingly easy-to-use molecular subtyping methods for L. monocytogenes. This review highlights key aspects of different L. monocytogenes subtyping methods and provides examples of their application in public health, food safety, population genetics, and epidemiology. A significant focus is on the application of subtyping methods to define L. monocytogenes subtypes and clonal groups, which may differ in phenotypic characteristics and pathogenic potential.
Assessment of MIST Alert™, a Commercial Qualitative Assay for Detection of Paralytic Shellfish Poisoning Toxins in Bivalve Molluscs
Authors: Mackintosh Fiona H , Gallacher Susan , Shanks Aileen M , Smith Elizabeth A 
Published: February 2020

Abstract
A recently developed commercial rapid test kit (MIST Alert™) was assessed for determination of the presence of paralytic shellfish poisoning (PSP) toxins in shellfish. Several commercially important shellfish species obtained from the UK shellfish toxin monitoring program, containing a range of total PSP toxicities as determined by the mouse bioassay (MBA), were tested. The kit detected toxin in all samples containing the European Community tolerance level of 80 μg saxitoxin (STX) equivalents/100 g shellfish flesh as determined by the MBA. With one exception, the kit detected toxin in all samples that contained &gt;40 μg STX equivalents/100 g according to the MBA. Among samples in which the MBA did not detect toxin, the kit disagreed in 25% of the tests, although further analysis by liquid chromatography (LC) and MBA of some samples confirmed the presence of toxins. These results suggest that MIST Alert may be suitable as an initial screen for PSP toxins as part of routine monitoring programs, thereby greatly reducing the number of MBAs. Trials were also performed by nonscientific personnel to evaluate the ease of use and interpretation of results obtained by MIST Alert. The results indicated that the kits could be readily used and accurately interpreted by individuals with no technical or scientific background.
Identity Preservation of Genetically Modified Organisms in the Food Chain: Requirements, Methods, and Costs
Authors: Brookes Graham 
Published: February 2020

Abstract
The use of the technology of genetic modification (GM) in European agriculture and the food supply chain is currently controversial. Because of strong anti-GM technology sentiments, the use of ingredients derived from plants containing GM have largely been eliminated from foods manufactured for direct human consumption by the food supply chain in much of the European Union (EU). During the past year, the attention of those opposed to the technology has turned to the use of GM ingredients in livestock production systems by incorporation of GM soy and maize in animal feed. A discussion is presented of the key issues relating to this subject, focusing on how supplies of GM or non-GM products are segregated or how their identities are preserved. The discussion is centered on GM maize and soybeans into which agronomic traits, such as herbicide tolerance and/or insect resistance, have been incorporated. These are currently the only crops into which some varieties containing GM have been approved for use in the EU.
Detection and Identification of Zeranol in Chicken or Rabbit Liver by Liquid Chromatography-Electrospray Tandem Mass Spectrometry
Authors: Fang Xiaoming , Chen Jiahua , Guo Dehua , Wang Guoquan 
Published: February 2020

Abstract
A sensitive, specific, and reliable liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for detection and identification of zeranol in chicken or rabbit liver. A homogenized liver sample was hydrolyzed with β-glucuronidase/arylsulfatase, and the hydrolysate was extracted with ethyl ether. The supernatant was evaporated to dryness, and the residue was dissolved in chloroform and re-extracted with sodium hydroxide. After acidification, the extract was cleaned up on a C18 solid-phase extraction cartridge and analyzed by electrospray LC-MS/MS in the negative ion mode. The multiple reaction monitoring transition from both m/z 321 to 277 and m/z 321 to 303 was monitored for confirmation, and the product ion of 277 was used for quantitation. Separation was performed on a Waters XTettra™ C18 column (50 × 2.1 mm, 3.5 μm) combined with a safeguard column (Symmetry C18, 20 × 3.9 mm, 5 μm), using a gradient elution with acetonitrile and 20mM ammonium acetate. Calibration curves were prepared and good linearity was achieved over the concentration ranges tested. For all liver samples fortified at 3 different levels of 1, 5, and 50 μg/kg, the overall recoveries and relative standard deviations were in the range of 61–90 and 8–13%, respectively. The limit of quantitation based on the assay validation was 1 μg/kg. The method had been used on a routine basis for detection and identification of zeranol in liver samples.
Sensitive and Rapid Spectrophotometric Methods for Determination of Anticancer Drugs
Authors: Nagaraja Padmarajaiah , Vasantha Ramanathapura A , Yathirajan Hemmige S 
Published: February 2020

Abstract
Sensitive, rapid, and simple spectrophotometric methods were developed for determination of the anticancer drugs vinblastine sulfate (VBS) and vincristine sulfate (VCS), which belong to the class of vinca alkaloids. The first method is based on the reaction of VBS and VCS with diazotized dapsone, forming yellow azo products with absorption maxima at 430 nm. The colored species obey Beer's law in the concentration range of 0.5–24 μg/mL for VBS and 0.5–12 μg/mL for VCS. The second method describes the reaction of VBS and VCS with iron(III) and subsequent reaction with ferricyanide in hydrochloric acid medium to yield blue products with absorption maxima at 750 nm. The Beer's law range for this method is 0.1–4 μg/mL for VBS and 0.5–10 μg/mL for VCS. With both methods, colored species were stable for 1 h. The methods are simple and reproducible and are applied for determination of VBS and VCS in pharmaceutical formulations. Commonly encountered pharmaceuticals added as excipients do not interfere in the analysis and the results obtained in the analysis of dosage forms agree well with the labeled contents.
Specific Detection of Clostridium botulinum Types A, B, E, and F Using the Polymerase Chain Reaction
Authors: Craven Kathy E , Ferreira Joseph L , Harrison Mark A , Edmonds Paul 
Published: February 2020

Abstract
Clostridium botulinum organisms generally produce 1 of 4 neurotoxin types (A, B, E, and F) associated with human illness. Neurotoxin type determination is important in identification of the bacterium. A polymerase chain reaction (PCR) method was developed to identify 24 h botulinal cultures as potential types A, B, E, and F neurotoxin producers as well as other clostridial species which also produce neurotoxins. Components of the PCR and amplification conditions were adjusted for optimal amplification of toxin gene target regions to enable simultaneous testing for types A, B, E, and F in separate tubes using a single thermal cycler. Each primer set was specific for its corresponding toxin type. A DNA extraction procedure was also included to remove inhibitory substances that may affect amplification. This procedure is rapid, sensitive, and specific for identification of toxigenic C. botulinum.
Determination of Fat Content and Fatty Acid Composition in Meat and Meat Products after Supercritical Fluid Extraction
Authors: Berg Hans , Dahlberg LenaDahlberg , Mathiasson Lennart 
Published: February 2020

Abstract
Two different relatively simple, commercially available supercritical fluid extractors (SFE), Leco and Foss-Tecator, were tested for the determination of total fat content in meat and meat products. The fatty acid composition in meat and meat products was also determined after the Foss-Tecator extraction in an aliquot of the extract. Total fat was determined by weighing after the different extraction procedures and the fatty acid composition by gas chromatography after hydrolysis and methylation of the extract. The results for total fat content agreed well with results from a standard method of Schmid, Bondzynski, and Ratzlaff, which uses conventional solvent extraction. Fatty acid composition was compared with the Bligh and Dyer extraction, and showed good agreement. The average relative difference between SFE and Bligh and Dyer of all fatty acids in the sample was &lt;3% for acids exceeding 0.5% of total fatty acid amount. The advantages of SFE over traditional methods are a much lower consumption of hazardous organic solvents and shorter extraction times. To obtain quantitative recoveries by SFE, ethanol was added to the extraction cells before extraction.
Simultaneous Determination of Vitamin A and β-Carotene in Dietary Supplements by Liquid Chromatography
Authors: Sundaresan P Ramnathan 
Published: February 2020

Abstract
Several liquid chromatography (LC) methods for analysis of vitamin A in oods and feeds have been previously reported but only a few have been applied in non-food matrixes. A validated LC method is needed for determination of vitamin A and β-carotene in the various matrixes presented by dietary supplements. The performance of a reversedphase method with methanol–isopropanol gradient elution was evaluated with standard retinyl derivatives and β-carotene. The reversed-phase method is capable of separating retinol from other derivatives such as retinyl acetate, retinyl palmitate, and β-carotene. Two types of extraction were used to extract the analytes from the dietary supplements: a hexane–methylene chloride extraction for soft-gel capsules containing β-carotene, and a direct solvent extraction for dietary supplements in tablet form. The direct solvent extraction consisted of treatment with ethanol and methylene chloride following addition of hot water (55°C). Results with the reversed-phase method for vitamin A and β-carotene in the products examined ( n = 8) indicated excellent method performance. The main form of vitamin A or β-carotene in dietary supplements was the all trans isomer. The reversed- phase method avoids saponification and is rapid, accurate, precise, and suitable for simultaneous determination of retinyl derivatives and β-carotene in dietary supplements.
Routine, High-Sensitivity, Cold Vapor Atomic Absorption Spectrometric Determination of Total Mercury in Foods after Low-Temperature Digestion
Authors: Dabeka Robert W , Bradley Peter , Mckenzie Arthur D 
Published: February 2020

Abstract
A cold vapor atomic absorption spectrometric method was developed for the subnanogram-per-gram determination of total Hg in a wide variety of foods. Foods were weighed into 50 mL polypropylene centrifuge tubes and dried without charring at 55°C in a circulating oven. Samples were then digested at 58°C with HNO3, HCl, and H2O2. After matrix modification with solutions of 2% Mg(NO3)2, 0.01% Triton X-100, and Cu(II) at 10 μg/mL, samples were analyzed by using a CeTAC Technologies M-6000A dedicated Hg analyzer. Based on a 2 g sample weight, the detection limit of the method over 12 batches averaged 0.30 ng/g wet weight and ranged from 0.03 to 0.6 ng/g. Recoveries of Hg added to 17 different foods, analyzed in a routine manner, averaged 97%, and individual recoveries ranged from 77 to 107%. Accuracy was confirmed by analysis of 7 biological reference materials from the National Research Council of Canada and the National Institute of Standards and Technology. Stabilization of low concentrations of Hg in solutions containing no sample was required to prevent loss of Hg from blanks. In a comparison of NaCl, potassium dichromate, and Au(III), chloride was much more effective for stabilization than the other two, and HCl was used for subsequent stabilization.
Comparison of Magnesium Sulfate and Sodium Sulfate for Removal of Water from Pesticide Extracts of Foods
Authors: Schenck Frank J , Callery Patrick , Gannett Peter M , Daft Jonathan R , Lehotay Steven J 
Published: February 2020

Abstract
Water-miscible solvents, such as acetone and acetonitrile, effectively extract both polar and nonpolar pesticide residues from nonfatty foods. The addition of sodium chloride to the resulting acetonitrile–water or acetone–water extract (salting out) results in the separation of the water from the organic solvent. However, the organic solvent layer (pesticide extract) still contains some residual water, which can adversely affect separation procedures that follow, such as solid-phase extraction and/or gas chromatography. Drying agents, such as sodium sulfate or magnesium sulfate, are used to remove the water from the organic extracts. In the present study, we used nuclear magnetic resonance spectroscopy to study the composition of the phases resulting from salting out and to compare the effectiveness of sodium sulfate and magnesium sulfate as drying agents. The study showed that considerable amounts of water remained in the organic phase after phase separation. Sodium sulfate was a relatively ineffective drying agent, removing little or no residual water from the organic solvent. Magnesium sulfate proved to be a much more effective drying agent.
Determination of Docosahexaenoic Acid and n-3 Fatty Acids in Refined Fish Oils by H-NMR Spectroscopy: IUPAC Interlaboratory Study
Authors: Igarashi Tomoji , Aursand Marit , Sacchi Raffaele , Paolillo Livio , Nonaka Michio , Wada Y ,   Collaborators:, Arata Y , Bildsoe H , Falcigno L , Fauhl C , Guillou C , Halvorsen J , Honma E , Ijuuin Y , Kushida K , Martin G J , Miyake Y , Optum O I , Oshima Y , Remaud G , Retif M , Robins R , Satake M , Shimidzu N , Tsuchiya F , Watanabe K , Watanuki C 
Published: February 2020

Abstract
A high-resolution proton nuclear magnetic resonance (NMR) method for determining the concentration (mg/g) of docosahexaenoic acid (DHA), the molar proportion (mol%) of DHA, and the molar proportion of total n-3 fatty acids in fish oils was validated by an IUPAC interlaboratory study (the Commission VI-6 on Oils, Fats, and Derivatives WG 3/98). Thirteen laboratories from 5 countries tested 6 pairs of blind duplicate fish oils: a refined tuna oil, 2 extracted tuna oils, an extracted bonito oil, an extracted salmon oil, and an extracted sardine oil ranging from 9 to 30 mol% DHA and from 20 to 35 mol% n-3 fatty acids. Before 1D-proton NMR measurements with 300–500 MHz instruments, oil samples were weighed and diluted with deuterochloroform solution containing ethylene glycol dimethyl ether as internal standard. To achieve precise performance, a detailed procedure for signal area measurement was described in the protocol, and all participants were instructed about the critical importance of following the protocol. Statistical performances with invalid and outlier data removed were as follows: repeatability relative standard deviations (RSDr) ranged from 0.91 to 2.62% and reproducibility relative standard deviation (RSDR) ranged from 1.73 to 4.27% for DHA concentration (mg/g); RSDr ranged from 0.39 to 2.06%, and RSDR ranged from 0.59 to 3.46% for mol% DHA; RSDr ranged from 0.23 to 0.90% and RSDR ranged from 0.85 to 2.01% for mol% total n-3 fatty acids. The method is expected to be recommended by IUPAC.