What's unreasonable about someone else choosing to wear a mask when they're sick? Even if it's not causing foodborne illnesses, it's still spreading the illness to other staff and customers.

Yeah parent poster added the masks into the comment, but the study did not mention them, but as the study says, the improper hand hygiene is responsible for large number of food poisonings.

Why the study doesn't talk about masks? Likely because it was done before pandemic so no one wore masks in that setting. Second thing is that generally they are concerned about serious diseases and if somebody would report catching a cold from eating at restaurant will simply be ignored. People are also less likely to report because it's harder to be sure where cold came from.

Though if diseases transferred via dirty hands caused 41% of outbreaks, then I believe it's safe to say that air borne disease is more likely to transfer that way, it's just a kind of diseases that no one cared about until we had covid, and only in 2020.