| 1. |
- Detmann, Edenio
(författare)
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Evaluation of Heating Times for Loss on Drying at 105 degrees C for Estimation of Laboratory Dry Matter in Animal Feeds
- 2023
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Ingår i: Journal of AOAC INTERNATIONAL. - : Oxford University Press (OUP). - 1060-3271 .- 1944-7922. ; 106, s. 261-266
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Tidskriftsartikel (refereegranskat)abstract
- Background Dry matter (DM) is a routine test for all animal feeds, facilitating feed comparisons and diet formulation. It is the most frequent test, yet the most challenging with respect to precision and accuracy. Objective Our objective was to evaluate the accuracy, repeatability, and physicochemical impacts of oven-drying times on LDM test results in animal feeds obtained by loss on drying (LoD) at 105 degrees C. Methods Eighteen primary samples collected from different feed sources were grouped into high-moisture (HM) and low-moisture (LM) content materials. The tested methods were based on LoD at 105 degrees C and Karl Fischer titration was adopted as the reference method. Test portions were oven dried at 105 degrees C for 3, 6, 12, 16, and 24 h, and test results were compared to the reference method. Test portions were also subjected to a color evaluation using a colorimetric technique. Results The method based on 3 h of drying provided the closest estimates to those obtained by Karl Fischer titration. Extending heating time (i.e., above 3 h) increased the bias, especially for HM feeds, which was attributed to a higher occurrence of non-enzymatic reactions. This was corroborated by the color of the residues, which became darker with increased heating time. The repeatability of LoD methods was considered adequate, ranging from 0.32 to 0.73%. Conclusion The LoD method based on the binomial 105 degrees C x 3 h minimizes the bias in the water recovery and causes less non-enzymatic browning in the test portions.
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| 2. |
- Detmann, Edenio
(författare)
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Variations in Methods for Quantification of Crude Ash in Animal Feeds
- 2023
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Ingår i: Journal of AOAC INTERNATIONAL. - : Oxford University Press (OUP). - 1060-3271 .- 1944-7922. ; 106, s. 6-13
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Tidskriftsartikel (refereegranskat)abstract
- Background Crude ash is categorized as an empirical method playing an important role in the nutritional interpretation of animal feeds, allowing indirect estimation of total organic matter (OM). Objective Our objective was to evaluate variations in laboratory procedures for crude ash quantification regarding physical parameters (i.e., time, temperature) and ashing aids and their influences on crude ash, repeatability, and discrimination power among feeds. Methods The "control" method was based on a simple ignition time of 3 h at 550 degrees C. The variations are briefly described: increasing ashing time to 6 h; increasing temperature to 600 degrees C; and using two 3 h ignition cycles at 550 degrees C with ashing aids inclusion between them: fresh air supply, fresh air supply plus distilled water, and fresh air supply plus hydrogen peroxide. A color evaluation was also performed using a colorimetric technique. Twenty-four study materials from eight different feed types were evaluated. Results The crude ash results differed among the method variations, but a consistent decrease in the estimates was observed when liquid aids were applied, which also improved repeatability. Ash residues did not present a consistent color pattern among methods, but the residues were darker when the control method was applied. Conclusion The method of obtaining ash residues in animal feeds based on 550 degrees C x 3 h does not have enough robustness and may overestimate crude ash in some feeds. Adjustments in either ignition time or temperature might improve crude ash test results, but the best test results are obtained using liquid ashing aids between two ignition cycles.
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| 3. |
- Jansson, Christer, et al.
(författare)
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Multiresidue Analysis of 95 Pesticides at Low Nanogram/Liter Levels in Surface Waters Using Online Preconcentration and High Performance Liquid Chromatography/Tandem Mass Spectrometry
- 2010
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Ingår i: Journal of AOAC INTERNATIONAL. - 1060-3271 .- 1944-7922. ; 93, s. 1732-1747
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Tidskriftsartikel (refereegranskat)abstract
- A new multiresidue method for the analysis of 95 pesticides and breakdown products with a wide range of physiochemical properties in surface and ground water using online solid-phase extraction coupled with HPLC/MS/MS is presented. Using an injection volume of only 500 mu L filtered water, an LOD in the 1-10 ng/L range was achieved for all but one substance, and recoveries were, with a few exceptions, in the 70-120% range. Large differences were found in the adsorption of pesticides on nine filter materials tested for filtration of the water samples. Filters of regenerated cellulose were chosen due to good recoveries and easy handling. Results from the proposed method were compared with results from previously used methods for 31 pesticides in 99 surface water samples, collected in 2008, with good agreement.
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| 4. |
- Johansson, Anders, 1966-, et al.
(författare)
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Genotyping of Francisella tularensis, the causative agent of tularemia
- 2010
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Ingår i: Journal of AOAC International. - 1060-3271 .- 1944-7922. ; 93:6, s. 1930-1943
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Tidskriftsartikel (refereegranskat)abstract
- Francisella tularensis is a facultative, intracellular, zoonotic pathogen and the causative agent of tularemia. Historically, F. tularensis has been subdivided into subspecies on the basis of phenotypic traits, including biochemical reactivity and virulence. More recently, a number of genotypic methods, ranging from relatively insensitive methods to full genome sequencing, have been used to investigate genetic diversity within F. tularensis. These analyses indicate that F. tularensis is a pathogen of low sequence diversity with pair-wise average nucleotide identities > 99.2% across subspecies. Nonetheless, genomic rearrangements and sequence deletions exist between and within F. tularensis subspecies, creating polymorphisms detectable by genotyping methods. Genetic subpopulations intermediate to the subspecies and strain level have been identified within F. tularensis subsp. tularensis and F. tularensis subsp. holarctica by several different typing methods. These genetic subpopulations have been associated with differences in disease severity, geographic distribution, and transmission patterns. For example, one F. tularensis subsp. tularensis subpopulation has been found to be significantly associated with mortality in humans. Additionally, genotypic analyses of Francisella spp. have provided information for use in the rational design of strain panels for validation of F. tularensis diagnostic tests. This review provides a guide to the various F. tularensis genotyping methods.
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| 5. |
- Löfström, Charlotta, et al.
(författare)
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Detection of salmonella in meat : Comparative and interlaboratory validation of a noncomplex and cost-effective pre-PCR protocol
- 2012
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Ingår i: Journal of AOAC International. - : Oxford University Press (OUP). - 1060-3271 .- 1944-7922. ; 95:1, s. 100-104
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Tidskriftsartikel (refereegranskat)abstract
- Cost-effective and rapid monitoring of Salmonella in the meat production chain can contribute to food safety. The objective of this study was to validate an easy-to-use pre-PCR sample preparation method based on a simple boiling protocol for screening of Salmonella in meat and carcass swab samples using a real-time PCR method. The protocol included incubation in buffered peptone water, centrifugation of an aliquot, and a boiling procedure. The validation study included comparative and interlaboratory trials recommended by the Nordic Organization for Validation of Alternative Microbiological Methods (NordVal). The comparative trial was performed against a reference method (NMKL 187, 2007) and a PCR method previously approved by NordVal with a semiautomated magnetic bead-based DNA extraction step using 122 artificially contaminated samples. The LOD was found to be 3.0, 3.2, and 3.4 CFU/sample for the boiling, magnetic bead-based, and NMKL 187 methods, respectively. When comparing the boiling method with the magnetic beads, the relative accuracy (AC), relative sensitivity (SE), and relative specificity (SP) were 98, 102, and 98%, respectively (Cohen's kappa index 0.95). When comparing results obtained by the boiling to the culture-based method, the AC, SE, and SP were found to be 98, 102, and 98%, respectively (kappa index 0.93). In the interlaboratory trial including valid results from 11 laboratories, apart from two falsepositive samples by the boiling method combined with PCR, no deviating results were obtained (SP, SE, and AC were 100, 95, and 97%, respectively). This test is under implementation by the Danish meat industry, and can be useful for screening of large number of samples in the meat production, especially for fast release of minced meat with a short shelf life. © 2012 Publishing Technology.
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| 6. |
- Taeymans, D., et al.
(författare)
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Acrylamide: Update on selected research activities conducted by the European food and drink industry
- 2005
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Ingår i: Journal of AOAC International. - 1060-3271 .- 1944-7922. ; 88:1, s. 234-241
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Tidskriftsartikel (refereegranskat)abstract
- This paper reviews the progress made by the European food and drink industry (CIAA) on acrylamide with regard to analytical methods, mechanisms of formation, and mitigation research in the major food categories. It is an update on the first CIAA review paper, "A Review of Acrylamide: An Industry Perspective on Research, Analysis, Formation and Control." Initial difficulties with the establishment of reliable analytical methods, in most cases, have now been overcome, but challenges remain in terms of the need to develop simple and rapid test methods and certified reference materials. Many trials have been conducted under laboratory and experimental conditions in a variety of foods, and a number of possible measures have been identified to relatively lower the amounts of acrylamide in food. Promising applications were studied in reconstituted potato models by addition of amino acids or use of asparaginase. In bakery wares, predictive models have been established to determine the role of ammonium carbonate and invert sugar in acrylamide formation. Studies in several commercial foods showed that acrylamide is not stable over time in roasted and ground coffee. Some progress in relatively lowering acrylamide in certain food categories has been achieved, but at this stage can only be considered marginal. Any options that are chosen to reduce acrylamide in commercial products must be technologically feasible and must not adversely affect the quality and safety of the final product.
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| 7. |
- Berg, H, et al.
(författare)
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Determination of fat content and fatty acid composition in meat and meat products after supercritical fluid extraction
- 2002
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Ingår i: Journal of AOAC International. - 1060-3271. ; 85:5, s. 1064-1069
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Tidskriftsartikel (refereegranskat)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 <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.
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| 8. |
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| 9. |
- Hellenas, K E, et al.
(författare)
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The HEATOX project
- 2005
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Ingår i: Journal of AOAC International. - 1060-3271. ; 88:1, s. 242-245
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Tidskriftsartikel (refereegranskat)abstract
- HEATOX is the acronym for a European Union-funded project entitled Heat-Generated Food Toxicants: Identification, Characterization, and Risk Minimization. Acrylamide will be the main experimental focus, but identification of unknown toxicants in heated carbohydrate-rich foods will also be attempted. The project includes research on formation chemistry, food technology, analytical methods, hazard characterization, and exposure assessment. The results will finally be used in risk assessment and risk management advice.
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