44 BULLETIN 1453, U. S. DEPARTMENT OF AGRICULTURE 



smoked meats which are to be stored uncooked is rather low, probably 

 less than 150°. 



Trials by the writer with shoulder butts weighing about 2 pounds 

 each show clearly that the period of hot-water immersion necessary 

 to heat the center of even small pieces of meat to a lethal temperature 

 would be impracticably long, even with water temperatures which 

 would result in some cooking. With protracted hot-water immersion 

 there would not only be clanger of leaching the meat but the attention 

 required to keep the temperature nearly constant would be so con- 

 siderable that the method does not seem to be applicable. 



Dipping cured meats in boiling water will not reach maggots 

 buried in the tissues unless immersion continues long enough to cook 

 the surface. 



FUMIGATION WITH HYDROCYANIC-ACID GAS 



In the summer of 1920, E. A. Back, in charge of stored product 

 insect investigations, Bureau of Entomology, in cooperation with 

 E. H. Kerr, in charge of laboratories, meat inspection division, 

 Bureau of Animal Industry, undertook some experiments with 

 hydrocyanic-acid gas against P. casei in cured meats. The unpub- 

 lished results of the analyses of fumigated meat, made under Kerr's 

 direction, showed that acid taken up by the meat during fumigation 

 was very rapidly dissipated when exposure to the gas was discon- 

 tinued, and that none of the acid was retained. Following these 

 experiments, the Bureau of Animal Industry authorized the use of 

 hydrocyanic-acid gas for fumigating meats in establishments subject 

 to Federal regulation (78). 



Griffin and Back (28) subsequently published anatyses of cured 

 meats which had been fumigated with the gas, using a dosage of 1 

 ounce of sodium cyanide per 100 cubic feet. These results showed 

 that some of the acid was absorbed and that small quantities were 

 retained for several days, but no conclusions were drawn regarding 

 the safety of such fumigated meats for use as human food. 



The writer has used this method of treating infested cured meats, 

 usually with dosages of about 2 ounces of sodium cyanide for each 

 100 cubic feet of space. No ill effects have been experienced from the 

 consumption of meats thus fumigated, which were largely disposed of 

 by sale to employees of the Bureau of Animal Industry in Washing- 

 ton. The safe use of such fumigated meats probably depends upon 

 airing them for several days after exposure to the gas and upon the 

 fact that they are cooked before being consumed. 



Hydrocyanic-acid gas, used as stated above, causes very high mor- 

 tality among skipper maggots, but a dosage of 2 ounces of sodium 

 cyanide per 100 cubic feet is not always to be depended upon to kill 

 all of those which are deep in the tissues of meat. On one occasion 

 about 25 hams and shoulders were examined after having been ex- 

 posed to the gas from Saturday afternoon to Monday morning. 

 Hundreds of skippers had crawled to the surface of the meat and 

 died there, and small heaps of dead maggots had accumulated on the 

 floor beneath some of the heaviest infestations, but inspection re- 

 vealed live larvae in nearly all of the pieces of meat. 



Eggs exposed at 70 to 80° F. to a dosage of 1 ounce of sodium 

 cyanide per 100 cubic feet for 24 hours were all killed. Adults, 



