Eventual limits of the current EU official method for evaluating milk adulteration of water buffalo dairy products and potential proteomic solutions. (1st September 2017)

• Record Type: Journal Article
• Authors: Caira, Simonetta; Nicolai, Maria Adalgisa; Lilla, Sergio; Calabrese, Maria Grazia; Pinto, Gabriella; Scaloni, Andrea; Chianese, Lina; Addeo, Francesco
• Is Part Of: Food chemistry. Volume 230(2017)
• Page Start: 482
• Page End: 490
• Publication Date: 2017-09-01
• Subjects: γ2- and γ3-casein -- Peptide markers -- Milk -- Cheese -- Proteomics; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2017.03.055
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Proteomics showed limits of the EU reference method assaying bovine in water buffalo milk. Water buffalo β-CN (f100-207) in plasminolysate generates false-positive results. Bovine β-CN (f1-25)4P and water buffalo β-CN (f1-28)4P as novel fraud markers. Dedicated MALDI-TOF-MS analysis as a second-generation reference method. Abstract: The European reference method (ERM) recognises the fraudulent addition of bovine (B) milk in water buffalo (WB) milk/dairy products based on concomitant isoelectric focusing (IEF) detection of B γ2 - and γ3 -CN fragments after corresponding plasminolysis. We here used proteomics to characterise false positive results occurring in the ERM as being due to WB β-CN(f100-209), which is also formed after plasminolysis of genuine WB milk/dairy products and comigrates in IEF with B γ2 -CN. These ERM limitations were overcome by a dedicated proteomic procedure based on loading of B/WB milk/cheese CN extracts on a hydroxyapatite column, in situ trypsinolysis and elution of B β-CN(f1-25)4P and WB β-CN(f1-28)4P proteotypic peptides. Based on their similar ionisation properties and resolution in MALDI-TOF-MS, these phosphopeptides were identified as suitable markers for detection of B material in WB milk/dairy products to a detection limit of 0.8% v / v . This proteomic procedure is here proposed as integrative/alternative to the ERM.