The video shows 10 people coming into the restaurant, with one singled out as an "infected" person. A fluorescent substance only visible under black light is applied onto that person's hands, representing germs from a cough or a sneeze. Each participant then goes about the buffet as they normally would, not considering a potential contamination.
At the end of the video, the participants are cast under black lights illuminating where the "infection" has spread.
The substance, used to signify the germs, can be seen on food, serving utensils and platters, and even on the faces of some of the participants.
(Score: 3, Informative) by Jiro on Saturday May 23 2020, @05:05PM
This shows that viruses "spread" this way in the sense that you can detect the virus on the place where it "spreads" to.
Most people are interested in spreading because spreading may lead to disease. They're not interested in spreading for its own sake. The coronavirus doesn't spread (in the sense of leading to disease) through surfaces or food contamination; even the CDC has been saying for a while that surfaces are "not thought to be the main way the virus spreads" [cdc.gov] (of course, no scientific organization will ever say that something has absolutely zero chance of spreading it, it's just very unlikely). They also say there is no evidence to support transmission of COVID-19 associated with food [cdc.gov].
Also, remember that bacteria can multiply in food, but viruses cannot.