(Funded by the U.S. Department of Energy and the U.S. Food and Drug Administration)
Scientists from the U.S. Food and Drug Administration, Northwestern University, and the Illinois Institute of Technology have found evidence that silver nanoparticles embedded in packaging used as an antimicrobial agent were able to seep into the dry food the packaging is meant to protect. The scientists created samples of silver nanoparticles and embedded them in polyethylene film wraps, which could hold various types of food items. They tested wheat flour, slices of cheese, ground rice, and spinach leaves. They found that the nanoparticles had made their way to all the foods, though to varying degrees. They found, for example, that there was far more contamination of the cheese than there was of the spinach leaves.

(Funded by the U.S. Food and Drug Administration)
This online post from the U.S. Food and Drug Administration states that “[m]icroplastics and nanoplastics may be present in food, primarily from environmental contamination where foods are grown or raised,” but “[c]urrent scientific evidence does not demonstrate that levels of microplastics or nanoplastics detected in foods pose a risk to human health.”