In making the water infusions 20 grams of the whole spices, with 200
cc of water, were boiled for forty-five minutes. This is approximately
the length of time that the spices are cooked in the ketchup in the
factory. The liquid was then filtered and from 0.1 to 5 cc of the
filtrate was used in 10 cc of tomato bouillon. The same organisms were
used as in the former experiments.
The tests showed that cinnamon and cloves were the strongest
antiseptically. These checked growth when used in small amounts, but
it required 3 cc of the cinnamon and 1 cc of the cloves to inhibit the
growth of the mold. Mustard, paprika, and cayenne pepper checked growth
also, but 5 cc, the highest strength used, did not inhibit growth. The
ginger, mace, and black pepper had no apparent effect in the quantities
used.
The effect of the spices on the development of the yeast was somewhat
different from their effect on Penicillium. The cinnamon showed the
strongest action, 3 cc being effective, whereas 5 cc of the cloves was
required. The cayenne pepper came next in effectiveness, and after that
the black pepper. The ginger, mace, and mustard solutions had no effect
in the strengths used.
The remainder of the spice infusions were kept in glass-stoppered
bottles in the laboratory, and in a few weeks’ time there was a coating
of mold formed over the surface of the mace, the mustard, and the
black and cayenne peppers. The paprika had small, stunted colonies
dotting the surface.
At the time that these experiments were made a quantity of the ground
spices were placed in large petri dishes and water was added to make a
heavy paste. One set of these was inoculated with the mold, and another
set with the yeast, and all were kept in a warm place. No development
of either organism appeared on the cinnamon, cloves, or mustard; on the
others a growth first showed in three days. On a normal medium growth
appears in twenty-four hours. On the mace, paprika, and cayenne pepper
the Penicillium and yeast with which the pastes were inoculated were
overgrown in a few days with black mold (_Rhizopus nigricans_).