Result: At the end of the cure 9 of the hams were found to be sour, while 11 remained sweet. Of the 9 hams which became sour, 1 showed very pronounced souring in the body and in the shank as well, 3 showed very pronounced souring in the body, 1 showed pronounced souring in the body, and 4 slight souring in the body. The bone marrow of the femur was tested in all of the sour hams and was found to be sour in 7. In 2 of the sour hams which showed slight souring in the body the souring noted in the meat had not extended through to the bone marrow.
Tierce No. 4 (regular cure).—This tierce contained 20 hams of the same average weight as those in tierce No. 3, and, like the latter, were pumped in both shank and body, but were not injected with culture. This tierce was put down to serve as a check on tierce No. 3 and was held under exactly the same conditions, the only difference being that these hams were not injected with culture.
Result: At the end of the cure the hams were carefully tested and all were found to be perfectly sound and sweet.
Results of Experiment I.
| No. of tierce. | Number of hams. | Average weight of hams Pounds. | Cure. | How pumped. | Treatment. | Condition at end of cure. | |
|---|---|---|---|---|---|---|---|
| Number of sour hams | Percentage of sour hams | ||||||
| 1 | 20 | 12-14 | Fancy | Shank only | Each ham injectedwith 10 c. c. of culture. | 19 | 95 |
| 2 | 20 | 12-14 | do | do | Not injected with culture;check on tierce 1. | 0 | 0 |
| 3 | 20 | 14-16 | Regular | Shank and body | Each ham injectedwith 10 c. c. of culture. | 9 | 45 |
| 4 | 20 | 14-16 | do | do | Not injected with culture;check on tierce 3. | 0 | 0 |
Three hams from each tierce were selected for bacteriological and histological examination. From tierces 1 and 3, which contained the injected hams, three of the most pronounced “sours” were selected from each tierce. In examining the hams bacteriologically the following method was adopted: The hams were sectioned near the center of the body and the larger or butt end turned up so as to expose the cut surface. A cross section of a ham thus cut is shown in figure 3.
Cultures were taken at the points indicated by the numbers and from the exposed bone marrow of the femur by first searing the surface, and then taking out plugs of the meat or marrow by means of sterile instruments. The plugs of meat or marrow were dropped into tubes containing egg-pork medium and pushed to the bottom of the tubes by means of a sterile platinum wire. In the cultures made from the sour hams from tierces 1 and 3, which were injected with culture, the bacillus with which these hams were injected was found in practically every culture, although it was sometimes absent in the cultures taken at points near the skinned surfaces of the hams (i. e., at points 1, 4, and 5 in fig. 3). In the cultures taken from the meat, the bacillus was not always present in pure culture, but this is not to be wondered at when we remember that the pickling fluids often contain large numbers of bacteria of various kinds, and these, of course, find their way into the hams in the pickling fluids. Especially is this true of the hams which are pumped in the body, where bacteria are actually pumped into the bodies of the hams in the pumping pickle. In the case of hams which are not pumped in the body, the pickle bacteria do not appear to penetrate the body of the ham to any great depth.
In figure 3 the plus signs after the figures represent the distribution of the sour-ham bacillus in one of the hams from tierce 1, and this may be taken as a typical example of the other sour hams which were examined in this experiment. It should be explained that the shaded areas are not intended to represent the actual limits of souring, but simply the areas in which the sour odor was most pronounced and from which it could be readily obtained with the trier. In comparing the regular and mild cure hams, it was found that the areas of souring as defined with the trier were more restricted in the regular cure hams, and this was undoubtedly due to the additional pumping which these hams received, whereby the growth of the bacillus was partially inhibited.
Fig. 3.—Cross section through body of artificially soured ham, showing sour areas and points at which cultures were taken. Darker shading indicates sour area in hams pumped in body and shank; light shading indicates sour area in hams pumped in shank only; figures indicate points at which cultures were taken; plus signs indicate presence of bacillus; minus sign indicates absence of bacillus; X indicates point of inoculation.