In the pronounced sours, termed “stinkers,” the odor pervades the entire ham, and is of a distinctly putrefactive quality.
In shank sours, the souring is more or less confined to the shank, or the region about the tibio-femoral articulation, but may extend upward into the lower portion of the body of the ham.
METHOD OF DETECTING SOUR HAMS.
Souring is detected and located by means of a pointed metal instrument known as a “ham trier,” which resembles a long, slightly flattened ice pick. The trier is thrust into the ham at different points along the bone, rapidly withdrawn, and the odor which clings to the metal noted. The trained inspector works very rapidly, and is able to detect even the slightest sour or off odor which might be imperceptible to one not trained to the work. At the end of the cure all hams are tested with the trier under the supervision of Government meat inspectors.
Hams are also given what is called the “30-day inspection” by plant inspectors during the process of curing. An average ham weighing from 14 to 16 pounds requires about 60 days to cure, and at the end of 30 days a certain number of hams in each run are usually tested to see how the cure is progressing. If no sour hams are discovered at this inspection the packer knows that the cure is progressing satisfactorily, and moreover he feels sure that his hams will finish satisfactorily, for experience has taught him that souring develops within the first four weeks of the curing period, and if his hams are sweet at the end of this time, he can feel practically sure that no sours will develop later on.
THEORIES IN REGARD TO HAM SOURING.
The theories as to the cause of souring are many and varied. The majority of them are pure speculation and have no foundation upon observed facts. A few of these theories may be enumerated to show how wide and varied has been the speculation upon this subject.
A theory which is quite prevalent among packing-house employees attributes souring to overheating of the animal previous to slaughter, but tests were made by driving hogs to the point of exhaustion just prior to slaughter and curing the hams from these animals in comparison with hams taken from animals which had been rested prior to slaughter, with no difference in the cured product; that is, the hams taken from overheated hogs cured equally as well as those taken from rested hogs.
Another theory attributes souring to a diseased condition of the meat. Prior to the enforcement of the Federal regulations governing meat inspection there might have been some ground for such a supposition, but this theory could not hold at the present time, in view of the thorough and efficient inspection now in force, for it can be safely said that no diseased meat now passes the Government inspectors, and therefore no diseased meat goes into cure in inspected houses. In order to test this theory, however, hams were secured from a number of condemned animals which showed various diseased conditions, such as hog cholera, pyemia, septicemia, scirrhous chord, etc., and these hams were cured in comparison with hams taken from normal hogs. It was found that the hams taken from the diseased hogs cured equally as well as those taken from healthy hogs. The hams from the diseased hogs were destroyed after the experiment, as the meat taken from diseased animals was of course not considered fit for consumption, the object of the experiment being merely to determine whether or not souring is caused by diseased conditions.
Another theory attributes souring to imperfect or too rapid chilling of the meat before it is put in pickle, and places the blame upon the refrigeration. According to this theory, souring results when the meat is chilled too suddenly, the idea being that by the rapid congealing of the juices of the meat a coating is formed on the outside of the ham whereby the animal heat is prevented from escaping from the interior, leaving the meat next to the bone at a higher temperature than the outside of the ham.