Food fraud, even when not in the news, is ubiquitous and demands the development of innovative strategies to combat it. A new non-targeted method (NTM) for distinguishing spelt and wheat is described, which aids in food fraud detection and authenticity testing. A highly resolved fingerprint in the form of spectra is obtained for several cultivars of spelt and wheat using liquid chromatography coupled high-resolution mass spectrometry (LC-HRMS). Convolutional neural network (CNN) models are built using a nested cross validation (NCV) approach by appropriately training them using a calibration set comprising duplicate measurements of eleven cultivars of wheat and spelt, each. The results reveal that the CNNs automatically learn patterns and representations to best discriminate tested samples into spelt or wheat. This is further investigated using an external validation set comprising artificially mixed spectra, samples for processed goods (spelt bread and flour), eleven untypical spelt, and six old wheat cultivars. These cultivars were not part of model building. We introduce a metric called the D score to quantitatively evaluate and compare the classification decisions. Our results demonstrate that NTMs based on NCV and CNNs trained using appropriately chosen spectral data can be reliable enough to be used on a wider range of cultivars and their mixes.

The EU commission established Regulation (2017/1495) in 2017 to reduce Campylobacter on chicken skin and to decrease the number of human cases of campylobacteriosis attributable to the consumption of poultry meat. A Process Hygiene Criterion based on colony-forming unit data was set to a maximum of 1000 CFU Campylobacter spp. per gram chicken neck skin at slaughterhouses. Confronted with stressors, including cold, oxidative stress or antibiotic treatment, live cells may enter into a viable but non-cultivable state (VBNC) and lose the ability to grow, in reference to the plate count ISO 10272-2:2017 method, but still possess the potential to recover and cause infections under favorable conditions. In this study, a droplet digital PCR combined with the intercalating dye propidium monoazide (PMA) was established for quantification of C. coli and C. jejuni in chicken meat rinses. The PMA was used to inactivate DNA from dead cells in this technique. This method was successfully validated against the reference method according to ISO 16140-2:2016 for accuracy and relative trueness. Additionally, it presented a 100% selectivity for Campylobacter jejuni and C. coli. Moreover, the technical measurement uncertainty was determined according to ISO 19036:2019, and the applicability of ddPCR for quantifying C. coli and C. jejuni in chicken meat rinses was investigated on naturally contaminated samples from slaughterhouses and supermarkets. Results obtained from this study demonstrated a strong correlation to qPCR as well as the classical microbiological reference method.

Objective: Determination of the sunburn protection provided by a sunscreen product is required globally for sales of these products. Over the past 80 years, many aspects of determining the protection ‘factor’ have evolved and been modified, with varying levels of impact on the sunburn protection factor (SPF) value. In order to compare new non‐invasive and in vitro methods against traditional SPF test protocols, a large, multi‐center clinical trial was conducted to establish the level of equivalence of these new methods with the current codified testing standard ISO24444 ([1]: Cosmetics – sun protection methods – in vivo determination of the sun protection factor (SPF), 2019). This report reports the variability found in the in vivo determination of SPF values.Methods: Thirty‐two products of varying levels of sunburn and UVA protection, in a variety of formulation vehicles and ultraviolet (UV) filter combinations and concentrations, were coded and sent to pre‐qualified in vivo SPF testing laboratories. The products were divided into eight product groups (four products per product group). For each product group, samples were sent to four laboratories (across product groups, a total of 12 laboratories participated). Precision and trueness estimates were calculated separately for each product group. ‘Expected’ SPF values were not provided to the test laboratories. However, laboratories were informed as to whether the ‘true’ SPF was less than or greater than 25.Results: Interlaboratory variability for samples was proportional to the SPF of the products, with high SPF products having higher variability. Intra‐laboratory variability (repeatability) was much lower than the interlaboratory variability.Conclusions: This study highlights the fact that the interlaboratory variability of SPF results is considerable and is likely greater than expected by the public and regulatory bodies.

Objective: To perform a comprehensive statistical characterization of the Double Plate method (ISO 23675) as a potential in vitro alternative to the in vivo reference method (ISO 24444:2019) for determining the sun protection factor (SPF).Methods: Five qualified laboratories were involved in testing the Double Plate method, as part of a large‐scale ring test conducted by the International Consortium ‘ALT‐SPF’. About 32 sunscreen products, reflecting diverse global formulations, were tested using both the in vivo reference method and the Double Plate method. This method employs spectrophotometric measurements of sunscreen applied to UV‐transparent plates with standardized robotic application to minimize the variability. A mathematical adjustment was introduced to address the initial bias compared to the reference method and further assessed in a follow‐up ring test with 12 products, including ISO standards.Results: The Double Plate method exhibited very high intra‐ and inter‐laboratory reproducibility throughout the study, consistently meeting the precision criteria set by ISO/TC217/WG7. Following the mathematical adjustment, the accuracy significantly improved, demonstrating a close alignment with the reference method.Conclusion: The Double Plate method demonstrates excellent reproducibility and, following optimization, high accuracy for the SPF determination. These findings endorse the Double Plate method as a robust and ethical in vitro alternative to the in vivo reference method for SPF testing. This paved the way for its publication as a new ISO standard (ISO 23675), in December 2024, supporting consumer safety and informed product choices.

Background: Measurement uncertainty is typically expressed in terms of a symmetric interval y±U, where y denotes the measurement result and U the expanded uncertainty. However, in the case of heteroscedasticity, symmetric uncertainty intervals can be misleading. In this paper, a different approach for the calculation of uncertainty intervals is introduced. Methods: This approach is applicable when a validation study has been conducted with samples with known concentrations. In a first step, test results are obtained at the different known concentration levels. Then, on the basis of precision estimates, a prediction range is calculated. The measurement uncertainty for a given test result can then be obtained by projecting the intersection of the test result with the limits of the prediction range back onto the axis of the known values, now interpreted as representing the measurand. Results: It will be shown how, under certain circumstances, asymmetric uncertainty intervals arise quite naturally and lead to more reliable uncertainty intervals. Conclusions: This article establishes a conceptual framework in which measurement uncertainty can be derived from precision whenever the relationship between the latter and concentration has been characterized. This approach is applicable for different types of distributions. Closed expressions for the limits of the uncertainty interval are provided for the simple case of normally distributed test results and constant relative standard deviation.