From milk to diet: feed recognition for milk authenticity

Area of Science:

• Molecular Biology
• Animal Science
• Food Science

Background:

• Animal-derived food products can potentially contain DNA from feed sources.
• Understanding the transfer of plant DNA into animal milk is crucial for food traceability and authenticity.

Purpose of the Study:

• To confirm the presence of plant-derived plastid DNA in animal milk.
• To develop and validate PCR-based methods for identifying plant DNA in milk.
• To investigate the relationship between animal diet and milk DNA content.

Main Methods:

• Experimental feeding of goats with defined plant diets (oats, ryegrass, X-triticosecale).
• DNA extraction from goat milk samples.
• Polymerase Chain Reaction (PCR) amplification targeting specific plant chloroplast genes (rbcL, matK, trnL).
• DNA sequencing and fragment analysis for species identification.
• Analysis of raw and commercial cow milk samples.

Main Results:

• Plant-derived rubisco (ribulose bisphosphate carboxylase, rbcL) DNA fragments were detected in 100% of analyzed goat milk samples.
• Sequences of amplified DNA fragments were 100% identical to the consumed plant species.
• Developed distinct PCR assays using matK and trnL markers for plant species identification.
• Confirmed the presence of plastidial plant DNA in cow milk, reflecting the diversity of their forage diets.

Conclusions:

• Plant plastid DNA is consistently transferred from the diet into animal milk.
• PCR-based molecular markers (rbcL, matK, trnL) are effective tools for detecting and identifying plant DNA in milk.
• These findings have implications for food authenticity, traceability, and understanding DNA transfer in food production systems.