In this experiment two tierces were put down, each containing 20 hams.
The hams weighed from 14 to 16 pounds and had received the usual
48-hour chilling. The pickling solutions employed were the regular
curing pickles of the establishment at which the experiment was carried
out. The curing pickle in one tierce was inoculated with 400 cubic
centimeters of a culture suspension of the bacillus, prepared in the
same manner as that used for the injection of the hams in tierce 2 in
Experiment II. A microscopic preparation made from a small drop of the
culture suspension before adding it to the pickle showed the bacilli
in large numbers, and in the 400 cubic centimeters of the suspension
there were millions of the bacteria. The curing pickle in the other
tierce was left untreated, the hams in this tierce serving as a check.
The tierces used in this experiment, as in all of the experiments, were
thoroughly cleaned with boiling water before the hams were placed in
them. The experiment was conducted in a pickling room which was held at
33° to 36° F., and the tierces were rolled three times during the cure.
The details of the experiment are as follows:
_Tierce 1._—Contained 20 hams, half of which were pumped in
both body and shank and half in the shank only. As soon as they
were pumped the hams were packed in the tierce. Sufficient
curing pickle to fill the tierce was then measured out in a
clean barrel and to it was added the culture suspension. The
culture was thoroughly mixed with the pickle and the latter was
then run into the tierce containing the hams.
Result: When tested at the end of the cure, two of the hams
which had been pumped in the shank only showed slight souring
in the body. The rest of the hams were sweet.
_Tierce 2._—Contained 20 hams which were pumped in the same
manner as those in tierce 1. The curing pickle was the same as
that used for tierce 1, but without the addition of culture.
This tierce was put down as a check on tierce 1, the hams
being cured under exactly the same conditions, but without the
addition of culture to the curing pickle.
Result: One of the hams which was pumped in the shank only
developed slight souring in the body. The remainder of the hams
were sweet.
Comparing tierce 1, which contained the inoculated pickle, with tierce
2, the check tierce which contained uninoculated pickle, we find
there was practically no difference in the final result. In tierce 1
two of the hams developed slight souring, while in tierce 2 one of
the hams became slightly sour. All of these hams had been pumped in
the shank only. The fact that one of the hams in the check tierce
developed slight souring was undoubtedly due to bacterial contamination
in pumping or in the handling which the hams underwent prior to
pickling, and the slight souring of the two hams in tierce 1 must
also be attributed to the same cause or causes, for had the souring
in these last hams resulted from the penetration of the bacteria from
the pickling solution a higher percentage should have become sour.
Furthermore, if the souring of the two hams in tierce 1 had resulted
from the penetration of the bacteria from the curing pickle, the
souring should have been general throughout the bodies of these hams,
whereas the souring was only evident around the bone and was slight in
degree.
From this experiment the conclusion would seem justified that the
bacillus which causes ham souring does not usually find its way into
the bodies of the hams from the curing pickle, although it would be
going too far, perhaps, to say that infection never takes place from
the curing pickle. The experiment, however, indicates clearly that the
curing pickles are certainly not the main channel through which the
hams become infected. In referring to the curing pickles, it should be
understood that we refer here to the pickling solutions in which the
hams are immersed, and not to the pumping pickles. The possibility of
infection through the pumping pickle will be discussed later.