Section 640.101 - General requirements(a)Heat stability test. Approximately 2 ml. of completely processed material of each lot shall not show any visible sign of gelation after heating in a 12 * 75 mm. stoppered glass tube at 57 °C for 4 hours.(b)pH. The pH of final container material shall be 6.8 ±0.4 when measured in a solution diluted to 1 percent protein with 0.15 molar sodium chloride.(c)Turbidity. The product shall be free of turbidity as determined by visual inspection of final containers.(d)Date of manufacture. The date of manufacture is the date of initiating the last valid measles or poliomyelitis antibody test (§ 640.104(b) (2) and (3) ) whichever date is earlier.(e)Labeling. In addition to complying with all applicable labeling required in this subchapter, labeling shall indicate that:(1) There is no prescribed potency for viral hepatitis antibodies.(2) The product is not recommended for intravenous administration.38 FR 32089, Nov. 20, 1973; 48 FR 13026, Mar. 29, 1983, as amended at 49 FR 23834, June 8, 1984; 50 FR 4140, Jan. 29, 1985; 51 FR 15611, Apr. 25, 1986; 55 FR 11013, Mar. 26, 1990; 63 FR 16685, Apr. 6, 1998; 64 FR 26287, May 14, 1999