Development of a Duck Genomic Reference Material by Digital PCR Platforms for the Detection of Meat Adulteration

Low-cost meat, such as duck, is frequently used to adulterate more expensive foods like lamb or beef in many countries. However, the lack of DNA-based reference materials has limited the quality control and detection of adulterants. Here, we report the development and validation of duck genomic DNA certified reference materials (CRMs) through the detection of the duck interleukin 2 (IL2) gene by digital PCR (dPCR) for the identification of duck meat in food products. The certified value of IL2 in CRMs was 5.78 ± 0.51 × 103 copies/μL with extended uncertainty (coverage factor k = 2) based on IL2 quantification by eight independent collaborating laboratories. Quantification of the mitochondrial gene cytb revealed a concentration of 2.0 × 106 copies/μL, as an information value. The CRMs were also used to determine the limit of detection (LOD) for six commercial testing kits, which confirmed that these kits meet or exceed their claimed sensitivity and are reliable for duck detection.

Assessing the level of confidence for expressing extended uncertainty: a model based on control errors in the measurement of ion activity

<p>A method for estimating the level of confidence when determining the coverage factor based on control errors is proposed, using the example of measurements of ion activity. Using information on tolerances and uncertainty, it is possible to establish a reasonable interval around the measurement result, within which most of the values that can be justified are assigned to the measured value.</p>

Microdisplacement Measurement Based on F-P Etalon: Processing Method and Experiments

Herein, a processing method is proposed for accurate microdisplacement measurements from a 2D Fabry–Perot (F-P) fringe pattern. The core of the processing algorithm uses the F-P interference imaging concentric ring pattern to accurately calculate the centre coordinates of the concentric ring. The influencing factors of measurement were analysed, and the basic idea of data processing was provided. In particular, the coordinate rotation by the 45-degree method (CR) was improved; consequently, the virtual pixel interval was reduced by half, and the calculation accuracy of the circle centre coordinate was improved. Experiments were conducted to analyse the influence of the subdivision and circle fitting methods. The results show that the proposed secondary coordinate rotation (SCR) by 45 degrees method can obtain higher accuracy of the centre coordinate than the CR method, and that the multichord averaging method (MCAM) is more suitable for calculation of the centre coordinate than the circular regression method (CRM). Displacement measurement experiments were performed. The results show that the standard experimental deviation of the centre of the circle is approximately 0.009 µm, and the extended uncertainty of the displacement measurement in the range of 5 mm is approximately 0.03 μm. The data processing method studied in this study can be widely used in the field of F-P interferometry.

Particularities of metrological control of non-contact systems for measuring the geometric dimensions of metal products.

OJSC “BSW–Management Company of the Holding “BMC”, non-contact systems for measuring the outer diameters of products are widely used for measuring geometric dimensions. Diameter measurement systems are used to obtain reliable, true and accurate measurements. The method that provides continuous and non – contact control of these systems is the light -and – dark method of measuring the diameter.To ensure the reliability of the measurement results, the diameter measurement systems must undergo metrological control – calibration. Calibration is carried out according to the developed methodology, which specifies the order of work, requirements for standards, processing of measurement and evaluation results, and registration of calibration results. To assess the extended uncertainty, a mathematical model is created that takes into account all the corrections that affect the result of the assessment, each of which is subjected to a thorough analysis.Calibration of diameter measurement systems allows to evaluate their real deviations in operating conditions, which allows to ensure the accuracy and reliability of measuring the geometric dimensions of metal products at all stages of its production.