A Protein-Based Approach for Greek Yogurt Authentication via an HRMS Technique (MALDI-TOF MS) and Milk Powder Detection as a Fraudulent Addition

The popularity of Greek-style yogurt (made from cow, ewe, and goat milk) has grown significantly in recent years thanks to its high protein content, nutritional value, and unique creamy texture, making it vulnerable to illegal practices, such as adulteration. In the present work, a fast and reliable matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)-based methodology was developed for the detection of yogurt adulteration with cow milk powder, exploiting the intact protein profile. An integrated protein-based workflow was established for the detection of as little as 1% cow milk powder addition into cow and goat milk yogurt. Simultaneously, markers for yogurt classification based on their animal origin (cow, ewe, or goat), type (traditional or strained), and thermal treatment of milk were revealed for the first time. Statistical analysis using chemometric tools, such as unsupervised principal component analysis (PCA) and supervised partial least squares discriminant analysis (PLS-DA) recognition techniques, were implemented for the discrimination/classification of the yogurt samples.