Comparative study of concatemer efficiency as an isotope-labelled internal standard for allergen quantification

Mass spectrometry-based methods coupled with stable isotope dilution have become effective and widely used methods for the detection and quantification of food allergens. Current methods target signature peptides resulting from proteolytic digestion of proteins of the allergenic ingredient. The choice of appropriate stable isotope-labelled internal standard is crucial, given the diversity of encountered food matrices which can affect sample preparation and analysis. We propose the use of concatemer, an artificial and stable isotope-labelled protein composed of several concatenated signature peptides as internal standard. With a comparative analysis of three matrices contaminated with four allergens (egg, milk, peanut, and hazelnut), the concatemer approach was found to offer advantages associated with the use of labelled proteins, ideal but unaffordable, and circumvent certain limitations of traditionally used synthetic peptides as internal standards. Although used in the proteomic field for more than a decade, concatemer strategy has not yet been applied for food analysis

Development and Validation of a Quantitative Method for Multiple Allergen Detection in Food Using Concatemer-Based Isotope Dilution Mass Spectrometry

Background Accurate food labeling is essential to protect allergic consumers. However, allergen contaminations may occur during the whole food production process. Reliable, sensitive, and robust methods for detecting multiple allergens in food are needed. Objective This work aims to develop and validate an LC coupled to tandem mass spectrometry (MS/MS) method for the detection and quantification of hazelnuts, peanuts, milk, and eggs in processed food products. Methods In-house-produced incurred test materials, cookies and chocolates, were used for the method development and validation. The quantification was based on the standard addition strategy using qualified reference materials as allergen protein standards and an innovative stable isotope-labeled concatemer as an internal standard. Results A method targeting 19 allergen-specific peptides was developed and validated in two laboratories, which strengthens its robustness. The AOAC INTERNATIONAL performance requirements for repeatability, intermediate precision, reproducibility, and recovery were reached for at least one peptide per allergen across both matrixes, and quantification limits complied with the action levels of the Food Industry Guide to the Voluntary Incidental Trace Allergen Labelling (VITAL (R)) Program Version 3.0. Conclusion The combination of incurred test materials, standard addition strategy, and stable isotope-labeled concatemer as an internal standard allowed us to develop and validate a robust method for detecting and quantifying multiple allergens in food with sufficient sensitivity to protect allergic consumers. Highlights: The combination of characterized incurred test material, calibration with certified reference material, a single stable isotope labelled concatemer and cross-lab validation result in the required standardization and harmonization in food allergen detection according to the stakeholders' group to assess the robustness of our method

Estimating the health-care usage associated with osteoarthritis and rheumatoid arthritis in an older adult population in ireland

An ageing population leads to increasing prevalence of age-related chronic conditions that present challenges to the health-care services. Despite this, in countries including Ireland, little is known about the health-care impact of conditions such as osteoarthritis or rheumatoid arthritis amongst older adults. A series of count models are developed to investigate the incremental health-care usage of individuals with either osteoarthritis or rheumatoid arthritis on the use of general practitioners (GP) services, outpatients' services, accident and emergency visits and inpatient nights. Both types of arthritic conditions lead to increased usage of GP and outpatients' services but not other hospital services. Differences in entitlements to care, as captured by the presence of a medical card in Ireland, lead to different health-care usage among arthritis sufferers. Translating the additional utilization into cost suggests a combined incremental annual cost of both types of arthritis of a,not sign13.6 million. Osteoarthritis and rheumatoid arthritis present challenges to health-care services in the context of an ageing population. In the case of Ireland the burden falls predominantly on primary health-care and outpatient services. Within the context of changing health-care service provision in Ireland, the results of this study have implications for future planning of service delivery

Selecting processing robust markers using high resolution mass spectrometry for the detection of milk in food products

Background Cow's milk allergy is one of the most reported food allergies in Europe. To help patients suffering from food allergies it is important to be able to detect milk in different foods. An analytical method that is gaining interest in the field of allergen detection is ultrahigh performance liquid chromatography-tandem mass spectrometry, where the analyte is a target peptide. When these peptide biomarkers are selected, the effect of food processing should be taken into account to allow a robust detection method. Objective This work aims at identifying such processing stable peptide markers for milk for the ultrahigh performance liquid chromatography-tandem mass spectrometry based detection of food allergens in different food products. Method Milk-incurred food materials that underwent several processing techniques were produced. This was followed by establishing tryptic peptide profiles from each matrix using ultrahigh performance liquid chromatography-high resolution mass spectrometry. Results A careful comparison of peptide profiles/intensities and the use of specific exclusion criteria resulted in the selection of eight peptide biomarkers suitable for application in ultrahigh performance liquid chromatography-tandem mass spectrometry based milk detection methods. One of these markers is an alpha-lactalbumin specific peptide, which has been determined to be stable in different incurred materials for the first time. Conclusions To our knowledge, this is the first systematic and experimentally based approach for the selection of suitable milk peptide biomarkers robust toward multiple, often applied food processing techniques for milk. Ensuring the exact knowledge of the food processing circumstances by starting from well-defined raw material and using fully controlled settings to produce incurred test material allowed the construction of a peptide database with robust markers. These robust markers can be used for the development of a robust detection method for milk in different food matrixes