Reference LC-MS/MS method to detect fresh cheeses adulteration with whey.

Area of Science:

• Analytical Chemistry
• Food Science
• Mass Spectrometry

Background:

• Adulteration of fresh cheeses with whey is a significant concern for food authenticity and consumer safety.
• Existing methods like SDS-PAGE have limitations in accurate quantitation and involve hazardous chemicals.
• A reliable and sensitive detection method is crucial for ensuring the quality of dairy products.

Purpose of the Study:

• To develop and validate a reference method for detecting whey adulteration in fresh cheeses.
• To utilize liquid chromatography coupled to mass spectrometry (LC-MS/MS) for precise identification and quantification of adulteration markers.
• To establish a method that overcomes the limitations of traditional techniques for routine analysis.

Main Methods:

• Sample preparation involved defatting with acetone and protein solubilization.
• Reversed-phase liquid chromatography with a C18 column was used for peptide separation.
• Mass spectrometry was performed using positive electrospray ionization in multiple reaction monitoring (MRM) mode to detect the marker peptide TPEVDDEALEK.

Main Results:

• The method successfully detected the marker peptide TPEVDDEALEK, indicative of whey adulteration.
• Method validation established a baseline concentration in authentic samples and an action level of 350 mg/kg for adulterated cheeses.
• The detection limit was 21 mg/kg, capable of identifying cheeses with as little as 10% adulteration, with high throughput analysis of 33 samples.

Conclusions:

• The developed LC-MS/MS method provides high precision, accuracy, sensitivity, and specificity for detecting whey adulteration in cow and buffalo milk cheeses.
• This method surpasses SDS-PAGE by avoiding toxic chemicals and offering superior quantitation capabilities.
• The technique is adaptable for detecting similar adulterations in cheeses made from other milk types and various dairy products.