Big Dairy Is Putting Microscopic Pieces of Metal in Your Food

—By Tom Philpott | Wed May 28, 2014 6:00 AM EDT

The rapid emergence of nanotechnology suggests that size does, indeed, matter. It turns out that if you break common substances like silver and nickel into really, really tiny particles—measured in nanometers, which are billionths of a meter—they behave in radically different ways. For example, regular silver, the stuff of fancy tableware, doesn't have any obvious place in sock production. But nano-size silver particles apparently do. According to boosters, when embedded in the fabric of socks, microscopic silver particles are "strongly antibacterial to a wide range of pathogens, absorb sweat, and by killing bacteria help eliminate unpleasant foot odor." (By most definitions, a particle qualifies as "nano" when it's 100 nanometers wide or less. By contrast, a human hair clocks in at about 80,000 nanometers in diameter.)