bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analytical Challenges: Bridging the Gap from Regulation to Enforcement
Authors: Eede Guy van den , Kay Simon , Anklam Elke , Schimmel Heinz 
Published: February 2020

Abstract
An overview is presented of the analytical steps that may be needed to determine the presence of genetically modified organisms (GMOs) or for analysis of GMO-derived produce. The analytical aspects necessary for compliance with labeling regulations are discussed along with bottlenecks that may develop when a plant product or a food sample is analyzed for conformity with current European Union GMO legislation. In addition to sampling and testing, other topics deal with complications that arise from biological and agricultural realities that may influence testing capabilities. The issues presented are intended to serve as elements to examine the different challenges that enforcement laboratories might face.
Production of Certified Reference Materials for the Detection of Genetically Modified Organisms
Authors: Trapmann Stefanie , Schimmel Heinz , Kramer Gerard Nico , Eede Guy van den , Pauwels Jean 
Published: February 2020

Abstract
Certified reference materials (CRMs) are an essential tool in the quality assurance of analytical measurements. They are produced, certified, and used in accordance with relevant ISO (International Organization for Standardization) and BCR (Community Bureau of Reference) guidelines. The Institute for Reference Materials and Measurements (IRMM; Geel, Belgium) has produced the first powdery genetically modified organism (GMO) CRMs in cooperation with the Institute for Health and Consumer Protection (Ispra, Italy). Until now, different weight percentages in the range of 0–5%for 4 GMOs in Europe were produced and certified: Bt (Bacillus thuringiensis)-11 and Bt-176 maize, Roundup Ready® soybean, and MON810 maize. Bt-11 and Bt-176 maize and Roundup Ready soybean were produced by IRMM on behalf of Fluka Chemie AG (Buchs, Switzerland). Characterization of used base material is the first step in production and is especially important for GMO CRMs. The production of powdery GMO CRMs and methods used for production control are described. Thorough control of homogeneity and stability are essential for certification of reference materials and ensure validity of the certificate for each bottle of a batch throughout a defined shelf-life. Because production of reference materials and their maintenance are very labor- and cost-intensive tasks, the usefulness of new types of GMO CRMs must be estimated carefully.
Kinetic Spectrophotometric Determination of Atenolol in Dosage Forms
Authors: Al-Ghannam Sheikha M , Belal Fathalla 
Published: February 2020

Abstract
A simple kinetic procedure is described for the determination of atenolol in its dosage forms. The procedure is based on coupling the drug with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole in pH 8 borate buffer at the boiling temperature for a fixed time of 30 min, and then measuring the absorbance of the reaction product at 460 nm. The absorbance–concentration plot is rectilinear over the range 5–50 μg/mL with a minimum detection limit of 1.3 μg (4.9 × 10−6M). The determination of atenolol by the fixed-concentration and rate-constant methods is also feasible with the calibration equations obtained, but the fixed-time method proved to be more applicable. The procedure was applied successfully to commercial tablets, and statistical analysis showed that the results compared favorably with those obtained by the official methods. The interference likely to be introduced from some coformulated drugs and the effect of sensitizers and surfactants on the performance of the proposed method were also studied. A proposed reaction pathway is presented.
Simultaneous Determination of Codeine and Pyridoxine in Pharmaceutical Preparations by First-Derivative Spectrofluorimetry
Authors: Molina-Díaz Antonio , Ramos-Martos Natividad , Navalón Alberto , Capitán-Vallvey Luis F 
Published: February 2020

Abstract
A method for the simultaneous determination of codeine and pyridoxine was developed, based on the measurement of their native fluorescence signals, by using first-derivative spectrofluorimetry to resolve the mixture. Codeine was measured at λem = 309 nm, and pyridoxine was measured at λem = 450 nm. Instrumental parameters were optimized, and the emission spectra were recorded between 275 and 475 nm, at λex = 255 nm and excitation and emission slit widths of 2.5 and 10 nm, respectively. Systematic studies on the influence of species usually present along with the analytes (such as caffeine, ascorbic acid, paracetamol, and thiamine) were also performed. The calibration graphs were linear over the ranges of 0.5–7.0 and 0.1–1.0 μg/mL for codeine and pyridoxine, respectively, and the relative standard deviations (n = 10) were about 3%. The method was successfully applied to the determination of codeine and pyridoxine in solutions of synthetic mixtures and in synthetic and semisynthetic pharmaceutical formulations.
Liquid Chromatographic Determination of S-Adenosyl-L-Methionine in Dietary Supplement Tablets
Authors: Zhou Joseph Ziqi , Waszkuc Ted , Garbis Spiro , Mohammed Felicia 
Published: February 2020

Abstract
A simple and reliable liquid chromatographic method was developed for the determination of S-adenosyl-L-methionine (SAM) in dietary supplement tablets. SAM in products was extracted with a phosphate buffer and separated from the mixture on a reversed-phase C8 column by ion-pair chromatography. A gradient mobile phase containing phosphate buffer, sodium octanesulfonate as the ion-pair reagent, and acetonitrile at a flow rate of 1.2 mL/min was used in the analysis. The UV detection wavelength was set at 257 nm. The calibration curve was linear over a range of 75–375 μg/mL for the SAM active ion with R2 = 0.9999. Replicate tests indicated good reproducibility of the method with a relative standard deviation of 0.9% (n = 8). The multiple extractions and recoveries from fortified products showed the high accuracy of the analysis. The use of the acidic buffer for SAM extraction and elution and the use of a fresh standard for each calibration to counteract the instability of the SAM compound significantly improved the accuracy of the method.
Spectrophotometric Determination of Organic Nitrogen by a Modified Lassaigne Method and Its Application to Meat Products and Baby Food
Authors: Demirata Birsen , Apak Resat , Afsar Hüseyin , Tor Izzet 
Published: February 2020

Abstract
A modified Lassaigne method was developed for N determination based on fusion of the organic substance with metallic Na, conversion of the cyanide in the aqueous leachate to thiocyanate by ammonium polysulfide treatment, and colorimetric measurement of the thiocyanate formed by the addition of excessive ferric ions in acidic medium. The mean molar absorptivity of the Fe(NCS)2+ complex at 480 nm is 2.96 × 103 L/mol·cm, enabling quantitation of 0.25–7.72 ppm N (linear range) in the final solution. The relative amounts of Na, (NH4)2S2, and Fe(III) with respect to nitrogen in the analyte were optimized. The developed method was successfully applied to the determination of N in various brands of baby food, and it was compared statistically with the conventional Kjeldahl and elemental analysis methods. Protein nitrogen in a number of meat products was also precisely determined by the developed method. Thus, the total digestion time of the conventional Kjeldahl method was reduced considerably (e.g., to approximately 15 min for a dried sample) with a relatively simple spectrophotometric method requiring no sophisticated instrumentation.
Rapid Detection of Single Cell Bacteria as a Novel Approach in Food Microbiology
Authors: D′Haese Eva , Nelis Hans J 
Published: February 2020

Abstract
Solid-phase cytometry (SPC) is a novel technique that allows rapid detection of bacteria at the single cell level, without the need for a growth phase. After filtration of the sample, the retained microorganisms are fluorescently labeled on the membrane filter and automatically counted by a laser scanning device. Each fluorescent spot can be visually inspected with an epifluorescence microscope connected to the ChemScan by a computer-driven moving stage. Depending on the fluorogenic labels used, information on the identity and the physiological status of the microorganisms can be obtained within a few hours. Although SPC was originally recommended for the determination of the total viable microbial count in water and other liquid samples, it may also be a promising technique for the detection and enumeration of bacteria in food samples, provided they can be isolated from the unfilterable matrix. The short detection time inherent in this approach is a considerable advantage over conventional plate counting, especially for slow-growing microorganisms. The basic principles of SPC are discussed as well as its potential for the detection of Mycobacterium paratuberculosis, a model example of a slow-growing bacterium in milk.
Confirmation of Phenylbutazone Residues in Bovine Kidney by Liquid Chromatography/Mass Spectrometry
Authors: Clark Susan B , Turnipseed Sherri B , Nandrea Gene J , Madson Mark R , Hurlbut Jeffrey A , Sofos John N 
Published: February 2020

Abstract
A confirmatory method is described for phenylbutazone (PB) residues in bovine kidney tissue. Ground kidney tissue is diluted with water, and the mixture is made basic with 25% ammonium hydroxide in water; the lipids are extracted with ethyl and petroleum ethers. The ether layer is discarded, and the tissue is acidified with 6N HCl. PB residues are extracted with tetrahydrofuran–hexane (1 + 4). The extract is passed through a silica solid-phase extraction column, and the eluate is evaporated to dryness. The residue is dissolved in acidified acetonitrile–water–acetic acid (50 + 49.4 + 0.6). A single quadrupole mass spectrometer coupled to a liquid chromatograph with an electrospray interface is used to confirm the identity of the PB residues in the kidney extract. Negative-ion detection with selected-ion monitoring of 4 ions is used. Sets of control and fortified-control kidney tissues (at 50, 100, and 200 ppb PB) and several kidney tissue field samples were analyzed for method validation. The method was tested further during the course of a survey to determine the incidence of PB residues in bovine kidney samples obtained from slaughterhouses across the country. In addition, the method was tested for use with an ion-trap mass spectrometer coupled to a liquid chromatograph, which allowed confirmation of PB at lower levels (5–10 ppb) in kidney tissue.
Determination of Cimetidine, Famotidine, and Ranitidine Hydrochloride in the Presence of Their Sulfoxide Derivatives in Pure and Dosage Forms by High-Performance Thin-Layer Chromatography and Scanning Densitometry
Authors: Kelani Khadiga M , Aziz Azza M , Hegazy Maha A , Fattah Laila Abdel 
Published: February 2020

Abstract
A selective, precise, and accurate method was developed for the determination of cimetidine (C), famotidine (F), and ranitidine hydrochloride (R·HCI)in the presence of their sulfoxide derivatives. The method involves quantitative densitometric evaluation of mixtures of the drugs and their derivatives after separation by high-performance thin-layer chromatography on silica gel plates (10 × 20 cm) with ethyl acetate–isopropanol–20% ammonia (9 + 5 + 4, v/v) as the mobile phase for both C and F and ethyl acetate–methanol–20% ammonia (10 + 2 + 2, v/v) as the mobile phase for R·HCI; Rf values for C, F, and R·HCI and their corresponding derivatives were 0.85 and 0.59, 0.73 and 0.41, and 0.56 and 0.33, respectively. Developing time was approximately 20 min. For densitometric evaluation, peak areas were recorded at 218, 265, and 313 nm for C, F, and R·HCI, respectively. The relationship between concentration and the corresponding peak area was plotted for the ranges of 5–50 μg/spot for C and 2–20 μg/spot for F and R·HCl. Mean recoveries were 100.39 ± 1.33, 99.77 ± 1.30, and 100.09 ± 0.69% for C, F, and R·HCI, respectively. The proposed method was used successfully for stability testing of the pure drugs in the presence of up to 90% of their degradates, in bulk powder and dosage forms. The results obtained were analyzed statistically and compared with those obtained by the official methods.
Measurement of α-Amylase Activity in White Wheat Flour, Milled Malt, and Microbial Enzyme Preparations, Using the Ceralpha Assay: Collaborative Study
Authors: McCleary Barry V , McNally Marian , Monaghan Dympna , Mugford David C ,   Collaborators:, Black C , Broadbent R , Chin M , Cormack M , Fox R , Gaines C , Gothard P , Home S , Howes; E , Johnson C , Keeping R , Koliatsou M , Lindhauer M , Marins de Sa R , Martin R , Monaghan D , Nees U , Nishwitz; R , Palmer G , Panozzo J , Recabarren J , Roumeliotis S , Seddig S , Solah V , Sonnet M , Themeier H 
Published: February 2020

Abstract
This study was conducted to evaluate the method performance of a rapid procedure for the measurement of α-amylase activity in flours and microbial enzyme preparations. Samples were milled (if necessary) to pass a 0.5 mm sieve and then extracted with a buffer/salt solution, and the extracts were clarified and diluted. Aliquots of diluted extract (containing α-amylase) were incubated with substrate mixture under defined conditions of pH, temperature, and time. The substrate used was nonreducing end-blocked p-nitrophenyl maltoheptaoside (BPNPG7) in the presence of excess quantities of thermostable α-glucosidase. The blocking group in BPNPG7 prevents hydrolysis of this substrate by exo-acting enzymes such as amyloglucosidase, α-glucosidase, and β-amylase. When the substrate is cleaved by endo-acting α-amylase, the nitrophenyl oligosaccharide is immediately and completely hydrolyzed to p-nitrophenol and free glucose by the excess quantities of α-glucosidase present in the substrate mixture. The reaction is terminated, and the phenolate color developed by the addition of an alkaline solution is measured at 400 nm. Amylase activity is expressed in terms of Ceralpha units; 1 unit is defined as the amount of enzyme required to release 1 μmol p-nitrophenyl (in the presence of excess quantities of α-glucosidase) in 1 min at 40°C. In the present study, 15 laboratories analyzed 16 samples as blind duplicates. The analyzed samples were white wheat flour, white wheat flour to which fungal α-amylase had been added, milled malt, and fungal and bacterial enzyme preparations. Repeatability relative standard deviations ranged from 1.4 to 14.4%, and reproducibility relative standard deviations ranged from 5.0 to 16.7%.
AOAC INTERNATIONAL Methods Committee Guidelines for Validation of Qualitative and Quantitative Food Microbiological Official Methods of Analysis
Authors: Feldsine Philip , Abeyta Carlos , Andrews Wallace H 
Published: February 2020

Abstract
Responding to a need for a guide for conducting Official Method validation studies of microbiological methods, AOAC utilized the experience of three microbiologists who have been active in the field of method validation. In collaboration, a document was prepared which covered the following areas: terms and their definitions associated with the Official Methods program (e.g., reference methods, alternative methods, and ruggedness testing), protocols and validation requirements for qualitative methods versus those for quantitative methods, the concept of the precollaborative study, ruggedness testing, tests for significant differences, performance indicators, and the approval process. After its preparation, this document was reviewed by the members of the Methods Committee on Microbiology and Extraneous Materials and by members of the Official Methods Board. Herein is presented the approved version of that document.
Assessment of Performance of Laboratories in Determining Acrylamide in Crispbread
Authors: Clarke Don B , Kelly Janet , Wilson Lesley A 
Published: February 2020

Abstract
A proficiency testing round was undertaken to assess the performance of laboratories to measure acrylamide in a sample of crispbread. Retail samples of crispbread were ground to a fine powder and after thorough mixing were packed in 40 g units for distribution. Ten samples were selected at random and analyzed in duplicate for acrylamide by liquid chromatography/mass spectrometry LC/MS). Standard statistical tests showed that the material was homogeneous for the purposes of proficiency testing. Test samples were distributed to 55 laboratories in 16 countries in Europe, North America, Australia, and the Middle East. The results were analyzed by standard proficiency testing statistical procedures, and laboratories were awarded z-scores on the basis of their reported results. Based on a target standard deviation (σp value) taken from the Horwitz equation, for a robust mean value of 1.2 mg/kg acrylamide, satisfactory results (z-score within ± 2 for those between 0.8 and 1.6 mg/kg) were obtained by 86% of the 37 laboratories that returned results. Only 1 laboratory was unsatisfactory and 4 had questionable results. About equal numbers of laboratories used gas chromatography (GC)/MS and LC/MS procedures with about 25% using MS/MS and one using GC with electron capture detection. There was no evident trend in performance or bias in results. GC/MS and LC/MS data were evenly distributed across the population of laboratories reporting results.
Multilaboratory Trial for Determination of Ceftiofur Residues in Bovine and Swine Kidney and Muscle, and Bovine Milk
Authors: Hornish Rex E , Hamlow Philip J , Brown Scott A 
Published: February 2020

Abstract
A multilaboratory trial for determining ceftiofur-related residues in bovine and swine kidney and muscle, and bovine milk was conducted following regulatory guidelines of the U.S. Food and Drug Administration, Center for Veterinary Medicine. The methods convert all desfuroyl-ceftiofur-related residues containing the intact β-lactam ring to desfuroylceftiofur acetamide to establish ceftiofur residues in tissues. Four laboratories analyzed 5 sets of samples for each tissue. Each sample set consisted of a control/blank sample and 3 control samples fortified with ceftiofur at 0.5 Rm, Rm, and 2 Rm respectively, where Rm is the U.S. tolerance assigned for ceftiofur residue in each tissue/matrix: 0.100 μg/g for milk, 8.0 μg/g for kidney (both species), 1.0 μg/g for bovine muscle, and 2.0 μg/g for swine muscle. Each sample set also contained 2 samples of incurred-residue tissues (one &gt; Rm and one &lt; Rm) from animals treated with ceftiofur hydrochloride. All laboratories completed the method trial after a familiarization phase and test of system suitability in which they demonstrated &gt;80%recovery in pretrial fortified test samples. Results showed that the methods met all acceptable performance criteria for recovery, accuracy, and precision. Although sample preparation was easy, solid-phase extraction cartridge performance must be carefully evaluated before samples are processed. The liquid chromatography detection system was easily set up; however, the elution profile may require slight modifications. The procedures could clearly differentiate between violative (&gt;Rm) and nonviolative (&lt;Rm) ceftiofur residues. Participating laboratories found the procedures suitable for ceftiofur residue determination.
Enumeration of Total Yeasts and Molds in Foods by the SimPlate® Yeast and Mold–Color Indicator Method and Conventional Culture Methods: Collaborative Study
Authors: Feldsine Philip T , Lienau Andrew H , Leung Stephanie C , Mui Linda A 
Published: February 2020

Abstract
The relative effectiveness of the SimPlate Yeast and Mold-Color Indicator method (Y&M–CI) was compared to the U.S. Food and Drug Administration's (FDA) Bacteriological Analytical Manual (BAM) method and the proposed International Organization for Standardization (ISO) method, ISO/CD 21527, for enumerating yeasts and molds in foods. Test portions were prepared and incubated according to the conditions stated in both the BAM and ISO methods. Six food types were analyzed: frozen corn dogs, nut meats, frozen fruits, cake mix, cereal, and fresh cheese. Nut meats, frozen fruits, and fresh cheese were naturally contaminated. All other foods were artificially contaminated with either a yeast or mold. Seventeen laboratories throughout North America and Europe participated in the study. Three method comparisons were conducted. In general, there was &lt;0.3 mean log count difference in recovery between the SimPlate method and the 2 corresponding reference methods. Moreover, mean log counts between the 2 reference methods were also very similar. The repeatability (sr) and reproducibility (sR) standard deviations were comparable between the 3 method comparisons. These results indicate that the BAM method and the SimPlate method are equivalent for enumerating yeast and mold populations in foods. Similarly, the SimPlate method is comparable to the proposed ISO method when test portions are prepared and incubated as defined in the proposed ISO method.
Detection of Botulinal Neurotoxins A, B, E, and F by Amplified Enzyme-Linked Immunosorbent Assay: Collaborative Study
Authors: Ferreira Joseph L , Maslanka Susan , Johnson Eric , Goodnough Mike ,   Collaborators:, Barash J , Boersma T , Brown E , Dykes J , Eliasberg S , Inami G , Lau D , Lindsey C , Ludwig G , Minor E , Parker T , Reddy R , Skinner G , Solomon H , Tepp B , Tetzloff R 
Published: February 2020

Abstract
An amplified enzyme-linked immunosorbent assay (amp-ELISA) was compared with the AOAC Official Method 977.26 for detection of Clostridium botulinum and its toxins in foods. Eleven laboratories participated and the results of 10 laboratories were used in the study. Two anaerobic culture media, tryptone peptone glucose yeast extract (TPGY) and cooked meat medium (CMM) were used to generate toxic samples with types A, B, E, and F botulinal strains. Nonbotulinal clostridia were also tested. The toxicity of each botulinal culture was determined by the AOAC method, and the cultures were then diluted, if necessary, to high (about 10 000 minimal lethal dose [MLD]/mL) and low (about 100 MLD/mL) test samples. The overall sensitivity of detection in TPGY and CMM cultures with the amp-ELISA was 94.7% at about 100 MLD/mL and 99.6% for samples with ≥10 000 MLD/mL toxicity. The amp-ELISA detection sensitivity for low toxin samples was 92.3% in TPGY and 99.4% in CMM. The false-positive rate ranged from 1.5% for type A to 28.6% for type F in TPGY, and from 2.4% for type A to 11.4% for type F in CMM. Most of the cross-reactivity was due to detection of other botulinal types, especially in high toxin samples. The amp-ELISA could be used to screen suspect cultures for botulinal toxins. Positive amp-ELISA samples would be confirmed by the AOAC reference method.