This study (open access) proposes a strategy to verify the authenticity of Mozzarella di Bufala Campana (MdBC). MdBC is, a Protected Designation of Origin (PDO) cheese, Buffalo breeds are highly similar genetically, so detecting foreign buffalo milk in commercial cheese is more complicated than identifying cow, goat, or sheep milk. Fraud involving cow milk is particularly concerning because it is cheaper and more widely available, especially during peak MdBC production seasons
The researchers used a reference set of sixty-four anonymized PDO MdBC and foreign mozzarella samples provided by the Italian Central Inspectorate for Fraud Repression and Quality Protection of the Agrifood Products and Food, Ministry of Agricultural and Forestry Policies (Rome, Italy). They used a sequential approach to verifying foreign milk species in buffalo mozzarella. As a first screen, the casein was separated on a polyacrylamide gel. This was generally sufficient to identify extraneous cows’ milk proteins. In a second stage, the isolate casein was then digested with trypsin and the peptides analysed by MALDI-ToF-MS.
In cases requiring confirmation, nano-liquid chromatography coupled to electrospray tandem mass spectrometry (nano-LC-ESI-MS/MS) is used in central state laboratories for the highly sensitive detection of extraneous milk proteins in PDO buffalo MdBC cheese. The researchers report that analysis of the pH 4.6 soluble fraction from buffalo blue cheese identified 2828 buffalo-derived peptides and several bovine specific peptides, confirming milk adulteration.
They conclude that, despite a lower detection extent in the pH 4.6 insoluble fraction following tryptic hydrolysis, the presence of bovine peptides was still sufficient to verify fraud. This integrated proteomic approach, which combines electrophoresis and mass spectrometry technologies, significantly improves milk adulteration detection.
Photo by Audric Wonkam on Unsplash
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