948 CONTROL OF BIOLOGICAL PRODUCTS 



to keep adequate records of processes, failure to take and keep records of the tempera- 

 ture of horses producing serum, inadequate separation of work on pathogenic spore- 

 bearing organisms from other operations, failure to keep horses under immunization 

 constantly protected against tetanus, and inadequate processes of sterilization. 



If, as the result of inspection, it is discovered that contaminated or impotent prod- 

 ucts are being produced, or if such defects are disclosed in any other manner, the li- 

 cense of the manufacturer may be suspended or canceled, or certain lots of products 

 may be withdrawn from trade channels. 



Purity. — It is important that extraneous living organisms be excluded during the 

 process of manufacture of most products. This is accomplished by requiring tests for 

 identity and purity of cultures prior to beginning manufacture of a batch of a product. 

 In some cases — e.g., bacterial vaccines — the presence of contaminating organisms 

 may be disclosed by so simple a procedure as the making of smears from finished ma- 

 terial. Thus a pertussis vaccine showing gram positive diplococci evidently has been 

 contaminated at some stage of the process of manufacture. 



Sterility. — Freedom of the final product from living organisms, excepting in the 

 few cases where these constitute the essential immunizing agents, is assured by the 

 methods of preparing the material, and by tests for sterility. Sterility tests are gen- 

 erally carried out on the bulk preparation prior to filling the trade containers, and 

 upon the contents of the latter as the material is ready for the market. The pro- 

 cedures for sterility testing must take cognizance of the presence of a preservative (if 

 one is present), and must therefore provide for adequate dilution so as to bring about 

 in the culture medium a concentration of the antiseptic sufficiently low to avoid its 

 inhibitory action. 



While agar plates and ordinary broth tubes are used to some extent abroad in 

 sterility testing, the most satisfactory means is to combine aerobic and anaerobic tests 

 in one container. This is accomplished by placing the material in fJasks of plain broth 

 where the amount of material to be tested is large, or by the use of two-armed fer- 

 mentation tubes after the design of Theobald Smith when the amount to be tested 

 is small. All the oxygen is driven off from the broth in the long closed arm just before 

 inoculation. Whichever container is used, the proportion of broth to inoculum should 

 be such that the preservative, if phenol or tricresol, shall not exceed i part in 10,000 of 

 the culture medium. 



It is desirable to test each lot of broth with an organism that does not grow very 

 readily to determine whether it is satisfactory for the purpose for which it is intended. 



Certain special preparations, notably rabies vaccine, may cloud the medium in the 

 fermentation tubes in such manner as to leave one in doubt as to whether contam- 

 inants are present. In such a case a transplant is made into a fresh tube of medium, 

 and this transplant should remain free from turbidity or sediment if the material is 

 free of living organisms capable of growing in the medium. 



The cultures used in sterility tests are examined after forty-eight hours' incuba- 

 tion, again after four days, and finally at the end of seven days. The two- and four- 

 day examinations are necessary because a contamination may develop and be ob- 

 servable at an earlier reading but disappear before the final observation. 



Labeling. — Under the regulations drawn up in accordance with the law of July i, 



