Comprehensive peptide marker identification for the detection of multiple nut allergens using a non-targeted LC–HRMS multi-method

Abstract

Food allergies have emerged as a global problem over the last few decades; therefore, reliable and sensitive analytical methods to ensure food safety for allergic consumers are required. The application of mass spectrometry is of growing interest in this field and several procedures based on low resolution tandem mass spectrometry using single tryptic peptides as analytical targets have recently been described. However, a comprehensive survey of marker peptides for the development of multi-methods is still missing, as is a consensus guide to marker identification. In this study, we therefore report a consistent approach to the development of liquid chromatography-mass spectrometry (LC-MS) multi-screening methods for the detection of allergens in food matrices. Proteotypic peptides were identified by a shotgun proteomics approach and verified through a thorough investigation of specificity and sensitivity. On the basis of this procedure, we identified 44 suitable tryptic marker peptides from six allergenic nut species and developed the first analytical LC-MS method for the detection of trace nut contaminations in processed foods using high resolution mass spectrometry (HRMS). The analysis of spiked matrix samples gave limits of detection (LODs) below 10 μg/g for several nuts; these LODs are comparable with routinely used methods such as ELISA and PCR. Notably, the HRMS approach can be used in an untargeted fashion to identify multiple allergens also retrospectively. In conclusion, we present here the so far largest consensus set of analytical markers from nut allergens and to the best of our knowledge the first multi-allergen method based on LC-HRMS.

Food authentication in real life: How to link nontargeted approaches with routine analytics?

“…These analyses are usually performed with triple quadrupole instruments. Nontargeted approaches are more relevant for primary method development [98,99]. Furthermore, nontargeted proteomics approaches are suitable for the identification of biological identities and have been used for the authentication of different animal species [100], milk and dairy products [101], fish [102,103], various plant foods [104,105], as well as for the detection of pathogens [106] and production methods [107,108].…”

Matrix-corrected mass spectrometry enables sensitive detection of food allergens and reveals widespread soy contamination of processed foods

“…Wheat was found in one corn flour [71], barley flour [A8], oat flour [A12], and rye flour [A15], while 3 ppm egg was found in one pasta product [55]. Lupin, a flowering plant in the legume family commonly ground into a gluten-free alternative to wheat flour, was not found in any sample, which is consistent with its infrequent use in the U.S.…”

Current (Food) Allergenic Risk Assessment: Is It Fit for Novel Foods? Status Quo and Identification of Gaps

“…Korte et al applied this method for multiallergen detection screening with the additional option for retrospective detection. [50] Koeberl and colleagues developed a method for the quantification, using MRM. [51] They authored an interesting paper where they reported pro and cons of both, immunological and MS methods and highlighted the importance of crucial selection of each antigen of signature peptides and related transitions.…”

“…Korte et al. applied this method for multi‐allergen detection screening with the additional option for retrospective detection . Koeberl and colleagues developed a method for the quantification, using MRM .…”