When eating out my wife and i have a line regarding food hygiene that once crossed cannot be uncrossed so unfortunately over the last 2 months 3 eating places that we frequently use crossed the line which is a hair found in the food. The 3 places were Gerrys on the boulevard, Finbar in Daun and D&C sourdough bakeshop in Valencia.
If that's the case, I think you may run out of places to eat pretty soon. On one occasion while in Cebu, I was having breakfast in a open fronted cafe with family, when my young niece said "look Uncle, there is a mouse" I turned to see the biggest rat I've ever seen, scurry past the table and chairs, just a hair's breadth away! But it's more fun in the Philippines. BTW, Michael Palin is doing a documentary series on Philippines at present, on UK TV, channel 5, Monday's normally at 9pm GMT, or available on You-tube
Thankfully the health risk from ingesting a single human hair is low. Hair is just keratin. Could there be something on it, a bacteria, sure it's possible but unlikely. I'm more concerned with what I can't see. Unwashed hands preparing the food. Vegetables and the like being washed with tap water. Besides, if I drew a line at an occasional hair in my food I wouldn't be able to eat at home either. Cough cough, hairball.
Yes a hair is not really the issue it's as you say above, what we can't see, if they are inattentive enough not to notice a hair in the food they are serving then what else could be in there Anyway not to worry plenty more eating places to choose from.