An integrated untargeted protein-based workflow for rapid detection of PDO feta cheese adulteration

Matrix-assisted Laser Desorption/Ionization Mass Spectrometry Time-Of-Flight (MALDI-TOF MS) has proved to be a powerful MS technique to address crucial authenticity challenges. Combining speed, reliability and straightforward analysis, MALDI-TOF-MS have led to its supremacy for complex assessment of food authenticity studies, like dairy products fraud, not only to prevent consumers’ health, but also to meet the established legislative frameworks.

Feta is a worldwide recognized Protected Designation of Origin (PDO) Greek cheese, highly ranked in the global market due to its special sensory characteristics. Although Feta is legally produced from sheep milk or a mixture of sheep and goat milk (the latter up to 30%), it may be subjected to the unlabeled addition of cow milk, due to its lower price combined with the reduced availability of ovine milk.

In this research work, an integrated untargeted protein-based workflow is presented, to address authenticity challenges in PDO feta cheese. Exploiting full capabilities of MALDI-TOF-MS profiling and chemometrics, discriminative models were built for the discrimination of authentic feta cheese, reaching the detection down to 1% adulteration level (cow milk). Potential markers were detected in authentic feta and white cheeses (prepared from cow milk), attributed to specific animal origin. The discriminative models showed high predictive ability, introducing a reliable approach in routine analysis. The methodology was successfully applied in detection of cow milk in sheep yoghurt, demonstrating that MALDI-TOF-MS can be applied as a reliable and rapid screening tool in the detection of dairy products adulteration.

Presenter: Prof. Nikolaos S. Thomaidis (National & Kapodistrian, University of Athens, Greece)