How long should a person wait to eat following a periodontal cleaning by an hygienist (i am hearing from one hour to 5 hours). can you please advise?

2 hours is fine.: If you had any numbing then you would wait until that has worn off. Otherwise, eating shouldn't be a problem after about 2 hours to let any inflammation in the gums to heal a bit. Also, it you had any granular antibiotic called Arestin or any other product placed into the space between your gums and teeth, remember to be careful when flossing so as to not disturb the antibiotic.

Wait eat: Yes this recommendation is reasonable. It gives your tissue some time to heal. Most hygienists numb you up as well. This will give the anesthetic time to wear off.