Assignment of a Reference Value of Total Cow’s Milk Protein Content in Baked Cookies Used in an Interlaboratory Comparison

Interlaboratory comparisons (ILC) in the food allergens field mainly rely on the use of consen-sus values per applied methodology or even per type of an ELISA test kit. Results may suggest good reproducibility, however, possible biases may not be recognized since metrological trace-ability to an independent reference is lacking. The work presented here utilizes isotope dilution mass spectrometry (IDMS) to assign a reference value of the total cow’s milk protein (TCMP) content in a baked cookie and its associated uncertainty. TCMP consists of several individual proteins of which five (representing 92 %) served us as markers for TCMP. Per marker one to four proteotypic peptides were selected for the quantification. These were synthesized and the mass fractions of respective reference solutions were determined with peptide-impurity cor-rected amino acid analysis to establish traceability to SI units. Stable isotope labelled (“heavy”) analogues of the proteotypic peptides were also synthesized and blended with extracts of the test material or the reference solutions for IDMS. Through careful measurement design minimizing biases, well-defined model equations were developed allowing appropriate estimation of the associated uncertainty. The determined reference value of 11.8 ± 1.1 mg TCMP / kg cookie was used for scoring of a novel ILC.

BREIDBACH Andreas;  NORGAARD Jorgen;  CUBERO LEON Elena;  MARTINEZ ESTESO Maria José; 

2022-12-01

MDPI

JRC128332

2304-8158 (online),   

https://www.mdpi.com/2304-8158/11/6/869#,    https://publications.jrc.ec.europa.eu/repository/handle/JRC128332,   

10.3390/foods11060869 (online),