I'm not sure we should cover our food in melatonin. People would recoil at the thought of pretty much any other hormone being added to our food supply. It's strange to me how Melatonin is so uncontrolled in usage, dosage, etc., despite being a hormone. The article suggests it's safer than current food additives, but I find that statement questionable. We don't understand the full effect of Melatonin on the human body…
I think it was here, where I read that the optimal dosage for melatonin was 0.3 mg (300 micrograms). The smallest OTC dosage you can get, is 1mg, and they sell 10mg pills. When I switched from 10mg to 0.3mg, my sleep improved drastically . Also, I stopped getting those really weird dreams. But I don't like taking stuff, and ended up stopping completely, a long time ago.
Melatonin only supplements mostly seem to start at around 2mg. There may be few of them at 1mg.
I can't tell if I've personally had any effects from melatonin specifically though. Sometimes I may have sleep issues and those nights, I think none of those supplements do anything.