220 Journal of Agricultural Research voi. xvii, no. 5 



Exposed to temperatures in the neighborhood of 50° C, trichina larvae 

 die if the application of heat is sufficiently long continued, apparently 

 as a result of exhaustion following excessive activity to which they are 

 stimulated by the heat. 



The longevity of trichina larvae freed from their cysts by artificial 

 digestion and kept at temperatures ranging between limits at which they 

 become quiescent from the effects of heat and cold, respectively, varies 

 inversely with the temperature. 



Methods of destroying trichinae b}^ heating at temperatures below the 

 thermal death point, which may be utilized in connection with the 

 preparation of certain kinds of cured pork products, appear not to be 

 applicable in the case of fresh pork. 



Upon the basis of the results of experiments recorded in this paper the 

 Bureau of Animal Industry has selected a temperature of 137° F. 

 (58-33° C.) as the minimum temperature to which pork and products 

 containing pork are required to be heated when cooked in establishments 

 operating under federal meat inspection.^ This temperature is several 

 degrees above the thermal death point of trichina larvae, thus providing 

 a certain margin of safety. 



LITERATURE CITED 

 (i) Fiedler, A. 



1864. BEITRAGE ZUR ENTWICKLUNGSGESCHICHTE DER TRICHINEN, NEBST 

 EINIGEN MITTHEn.UNGEN UBER DIE EINWIRKUNG EINZELNER MEDI- 

 CAMENTE u. ANDERER AGENTIEN AUF DIESELBEX. In Arch. Heilk., 

 Jahrg. 5, p. 1-29. 



(2) 



1864. WEITERE MITTHEILUNGEN UBER TRICHINEN. Ill Arch. Heilk., Jahrg. 5 

 p. 466-472, 511-520. 



(3) Fjord, N. J., and Krabbe, H. 



1868. EFFECTS OP HIGH TEMPERATURE ON TRICHINA SPIRALIS. (Translntion.) 



In Veterinarian, London, v. 41 (s. 4, v. 14), p. 323-328. 



(4) Haubner, Karl. 



1864. UEBER die TRICHINEN, MIT BESONDERER BERUCKSICHTIGUNG DER SCHUTZ- 

 MITTEL GEGEN DIE TRICHINENKRAXKHEIT BEIM MENSCHEN. In Mag. 



Gesam. Thierheilk., Jahrg. 30, Stuck 2, p. 129-176, pi. 2. 



(5) KucHENMEiSTER, and Leisering. 



1863. VERSUCHE MIT TRICHINEN. In Ber. Veterinarw. Konigr. Si^chs., 1862, 

 p. 114-120. 



(6) Leuckart, Rudolf. 



1886. THE PAR.\SITES of man, AND THE DISEASES WHICH PROCEED FROM THEM. 



Translated from the German, with the cooperation of the author, by 

 William E. Hoyle. xxvi, 771 p., 404 fig. Edinburgh. 



(7) Perroncito, E. 



1877. DIE TRICHINA SPIR.'^LIS IN it ALIEN. MITTHEH.UNG UBER EINEN FALL VON 

 TRICHINOSE IM INTERMUSKULOSEN BI.NDEGEWEBE EINES JAGDHUNDES. 



(Translation.) In Ztschr. Veterinarwiss., Jahrg. 5, Heft4/5, P- 200-203. 



' This requirement has reference to the temperature actually reached in the interior of the meat and 

 not merely to that of the water or oven in which it is cooked. It should also be understood that when 

 meat is cooked for purposes of sterilization because of conditions other than trichinosis a higher tempera- 

 ture is necessary than that sufficient to destroy trichina:. 



