52 



Studies of Aeration Methods 



[Oct. 



B. Hashed heef with definite additions of ammonio-magnesium 

 Phosphate of known nitrogen content. The meat preparations re- 

 ferred to in Table 3 acquired a content of er y stalline ammonio- 

 magnesium phosphate after their storage in an ordinary refrigerator. 

 We attributed the increased yield of ammonia nitrogen, as the 

 examinations progressed (Table 3), to the accumulation of am- 

 monium in the form of triple phosphate and other Compounds, as 

 a result of bacterial activity.^^ 



The capacity of the NaOH-NaCl method to eject all the ammo- 

 nium nitrogen from crystalline ammonio-magnesium phosphate in 

 meat was tested directly by adding weighed amounts of such phos- 

 phate, with known nitrogen content, to meat whose yield of am- 

 monia had been determined, in other portions, before the triple 

 phosphate was admixed. The analytic data are presented in Table 4. 



TABLE 4 



Data pertaining to the yield of ammonium nitrogen, by the NaOH-NaCl method, 



from meat and triple phosphate mixtures of known independent 



yields of ammonium nitrogen by the same method 



10 The meat was ordinary hashed beef, which had been thoroughly mixed by 

 hand before refrigeration. No attempt was made to prevent introduction of 

 bacteria. 



* The preparations referred to in Table 3 were used. 



t The calculated total was derived, for the meat, from the data f or the 

 nearest date (Table 3) ; for the phosphate, from the aeration data in Table 2. 

 Thus, for the first total (26.0 mg.) we calculated: (a) 26.886X0.21 = 5.646; 

 (fe) 0.2398X85 = 20.383; (c) 5.646 + 20.383 = 26.029. It is obvious that such 

 calculations are at best close approximations and that the average "loss" may 

 be due, in part, to overcalculation. 



