21 C.F.R. § 1250.44 Drinking utensils and toilet articles.
Title 21 - Food and Drugs
(a) No cup, glass, or other drinking utensil which may be used by more than one person shall be provided on any conveyance unless such cup, glass, or drinking utensil shall have been thoroughly cleaned and subjected to effective bactericidal treatment after each individual use. (b) Towels, combs, or brushes for common use shall not be provided.
Title 21: Food and Drugs
PART 1250—INTERSTATE CONVEYANCE SANITATION
Subpart C—Equipment and Operation of Land and Air Conveyances
§ 1250.44 Drinking utensils and toilet articles.

