You can produce such minuscule particles by using lasers, vibrations, plant extracts or even certain microorganisms. In one study, after a week of storage at room temperature, most regular strawberries were covered in fungus. Among those coated with chitosan and nano-silver, however, only 10% were spoiled. Freshly cut carrots coated with silver nanoparticles stayed fine for 70 days. Uncoated carrots lasted a mere four.