29 C.F.R. § 785.19 : Labor — REGULATIONS RELATING TO LABOR — WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR — STATEMENTS OF GENERAL POLICY OR INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS — HOURS WORKED — APPLICATION OF PRINCIPLES —REST AND MEAL PERIODS — Meal

(a) Bona fide meal periods. Bona fide meal periods are not worktime. Bona fide meal periods do not include coffee breaks or time for snacks. These are rest periods. The employee must be completely relieved from duty for the purposes of eating regular meals. Ordinarily 30 minutes or more is long enough for a bona fide meal period. A shorter period may be long enough under special conditions. The employee is not relieved if he is required to perform any duties, whether active or inactive, while eating. For example, an office employee who is required to eat at his desk or a factory worker who is required to be at his machine is working while eating. ( Culkin v. Glenn L. Martin, Nebraska Co., 97 F. Supp. 661 (D. Neb. 1951), aff'd 197 F. 2d 981 (C.A. 8, 1952), cert. denied 344 U.S. 888(1952); Thompson v. Stock & Sons, Inc., 93 F. Supp. 213 (E.D. Mich 1950), aff'd 194 F. 2d 493 (C.A. 6, 1952); Biggs v. Joshua Hendy Corp., 183 F. 2d 515 (C. A. 9, 1950), 187 F. 2d 447 (C.A. 9, 1951); Walling v. Dunbar Transfer & Storage Co., 3 W.H. Cases 284; 7 Labor Cases para. 61.565 (W.D. Tenn. 1943); Lofton v. Seneca Coal and Coke Co., 2 W.H. Cases 669; 6 Labor Cases para. 61,271 (N.D. Okla. 1942); aff'd 136 F. 2d 359 (C.A. 10, 1943); cert. denied 320 U.S. 772(1943); Mitchell v. Tampa Cigar Co., 36 Labor Cases para. 65, 198, 14 W.H. Cases 38 (S.D. Fla. 1959); Douglass v. Hurwitz Co., 145 F. Supp. 29, 13 W.H. Cases (E.D. Pa. 1956))
(b) Where no permission to leave premises. It is not necessary that an employee be permitted to leave the premises if he is otherwise completely freed from duties during the meal period.

29 C.F.R. § 785.19