Milk proteins and fat influence Ag migration from model dairy packaging containing silver nanoparticles

Area of Science:

• Food science
• Materials science
• Nanotechnology

Background:

• Silver nanoparticles (AgNPs) are used in food packaging.
• Understanding AgNP migration into food is crucial for safety.
• Milk is a complex food matrix with varying fat content.

Purpose of the Study:

• To investigate silver (Ag) migration from AgNP-loaded polyethylene films into bovine milk.
• To assess the influence of milkfat content on Ag migration.
• To characterize the form of migrated Ag in milk.

Main Methods:

• AgNP-loaded polyethylene films were stored in skim, 2% fat, and whole milk for 10 days at 20 °C.
• Ag migration levels were quantified.
• Migrated Ag was analyzed for its form (nanoparticles vs. ions) using electron microscopy and other techniques.
• Ag+ ion behavior in milk was studied.

Main Results:

• Ag migration into skim and 2% fat milk was comparable and higher than into whole milk.
• Ag migration into milk was significantly higher than into 50% aqueous ethanol, a common food simulant.
• Migrated Ag existed partly as nanoparticles, with milk proteins (casein, whey) and lactose influencing their transformation and composition.
• Observed efficient Ag+ transformation to Ag0 and Ag2O nanoparticles (5-70 nm).

Conclusions:

• Milk components, particularly proteins and lactose, significantly affect Ag migration dynamics and the form of migrated Ag.
• Current food simulants like aqueous ethanol may not accurately represent AgNP migration into milk.
• Further research is needed to establish appropriate food simulants for AgNP migration studies in complex matrices like milk.