CHEMICAL ANALYSES OF SOUR AND SOUND HAMS.
In order to determine whether there was any difference in regard to the penetration of the pickling fluids in the sour hams as compared with sound hams, a series of four sour hams were subjected to a chemical examination in comparison with four sound hams. All were sweet-pickle hams and were obtained from the same packing establishment. They were all of the same cure and the same approximate age (i. e., length of cure) and the same approximate weight.
In taking samples for chemical analysis, the following procedure was adopted: A section about 2-1/2 inches wide was cut from the center of the body. The two ends of this section were then trimmed off along the lines L-M and N-O, as shown in figure 2. Beginning at the skinned surface, four slices, A, B, C, and D, were then made, as indicated by the dotted lines. Slice B contained the bone in each instance. Slice D was practically all fat. Each slice was ground separately in a meat chopper and the sample thoroughly mixed before taking out portions for analysis.
Fig. 2.—Cross section through body of ham to show method of sampling for chemical analysis. A, slice below bone; B, bone slice; C, slice above bone; D, fat slice.
As all of the hams examined were mild-cure hams, that is, had been pumped in the shank only, the pickling fluids in order to reach the bodies of these hams had to penetrate chiefly from the skinned surface of the ham, as little if any penetration takes place through the thick skin of the ham.
The analyses[3] shown in the following tables therefore indicate the degree of penetration of the pickling fluids.
[3] These analyses were made by Mr. R. R. Henley, of the Biochemic Division, Bureau of Animal Industry.
Analyses of sour hams.
| No. | Description. | Slice. | NaCl. | KNO₃. |
|---|---|---|---|---|
| Per cent. | Per cent. | |||
| 1 | Sour body | A | 6.18 | 0.175 |
| B | 4.83 | .224 | ||
| C | 3.65 | .299 | ||
| D | 1.03 | .074 | ||
| 2 | do | A | 5.34 | .174 |
| B | 3.70 | .150 | ||
| C | 2.79 | .174 | ||
| D | 1.12 | .012 | ||
| 3 | do | A | 5.04 | .125 |
| B | 4.08 | .149 | ||
| C | 2.72 | .099 | ||
| D | 1.19 | .048 | ||
| 4 | do | A | 7.78 | .250 |
| B | 5.31 | .100 | ||
| C | 4.76 | .200 | ||
| D | 1.96 | .048 |
Analyses of sound hams.
| No. | Description. | Slice. | NaCl. | KNO₃. |
|---|---|---|---|---|
| Per cent. | Per cent. | |||
| 1 | Sound | A | 5.80 | 0.211 |
| B | 4.83 | .188 | ||
| C | 3.86 | .221 | ||
| D | 1.33 | .063 | ||
| 2 | do | A | 4.94 | .197 |
| B | 4.08 | .149 | ||
| C | 3.05 | .223 | ||
| D | 1.56 | .059 | ||
| 3 | do | A | 5.92 | .173 |
| B | 4.29 | .099 | ||
| C | 4.12 | .139 | ||
| D | 2.32 | .049 | ||
| 4 | do | A | 5.53 | .119 |
| B | 4.89 | .079 | ||
| C | 4.32 | .099 | ||
| D | 2.19 | .041 |
Taking an average of the four slices in each ham so as to get an average for the entire ham, and comparing the sour hams with the sound hams, we have the following comparison:
| NaCl. | KNO₃. | ||
| Average for 4 sour hams (entire ham) | per cent. | 3.84 | 0.143 |
| Average for 4 sound hams (entire ham) | do | 3.93 | .131 |
These figures show practically no difference between the sour and the sound hams as regards the sodium chlorid and potassium nitrate content of the entire ham.
If, now, we compare the bone slices—and these afford really a better basis for comparison, as in sour-body hams the souring is always more pronounced around the bone—we have the following figures:
| NaCl. | KNO₃. | ||
| Average for 4 sour hams (bone slice) | per cent. | 4.48 | 0.155 |
| Average for 4 sound hams (bone slice) | do | 4.52 | 0.129 |
Here, again, we find no essential difference between the sour and the sound hams, and we must conclude from these analyses that souring does not depend upon or result from a lack of penetration of the pickling fluids.
It seems probable that in mild-cure hams, which are pumped in the shank only, the souring begins in the upper portion of the shank and extends upward along the bone into the body of the ham, and that it takes place before the pickling fluid has penetrated to the interior of the ham. When the pickling fluid reaches the interior of the ham it tends to inhibit the souring, which, as will be shown later, is due to the development of bacteria within the bodies of the hams. The growth of the bacteria, however, within the bodies of the hams and the histological changes in the muscle fibers do not seem to interfere with the penetration of the pickling fluids.