Every housekeeper is familiar with molds which, under favorable
conditions of warmth and moisture, grow upon almost any kind of organic
material. This is seen in damp, warm weather, when molds form in a short
time on all sorts of starchy foods, such as boiled potatoes, bread,
mush, etc., as well as fresh, canned, and preserved fruits.
Molds develop from spores which are always floating about in the air.
When a spore falls upon a substance containing moisture and suitable
food it sends out a fine thread, which branches and works its way over
and into the attacked substance. In a short time spores are produced and
the work of reproduction goes on.
In the first stages molds are white or light gray and hardly noticeable;
but when spores develop the growth gradually becomes colored. In fact,
the conditions of advanced growth might be likened to those of a flower
garden. The threads--mycelium--might be likened to the roots of plants
and the spores to the flower and seeds.
Mold spores are very light and are blown about by the wind. They are a
little heavier than air, and drop on shelves, tables, and floor, and are
easily set in motion again by the movement of a brush, duster, etc. If
one of these spores drops on a jar of preserves or a tumbler of jelly,
it will germinate if there be warmth and moisture enough in the
storeroom. Molds do not ordinarily cause fermentation of canned foods,
although they are the common cause of the decay of raw fruits. They are
not as injurious to canned goods as are bacteria and yeasts. They do not
penetrate deeply into preserves or jellies, or into liquids or
semiliquids, but if given time they will, at ordinary room temperature,
work all through suitable solid substances which contain moisture.
Nearly every housekeeper has seen this in the molding of a loaf of bread
or cake.
In the work of canning, preserving, and jelly making it is important
that the food shall be protected from the growth of molds as well as the
growth of yeasts and bacteria.
To kill mold spores food must be exposed to a temperature of from 150°
F. to 212° F. After this it should be kept in a cool, dry place and
covered carefully that no floating spore can find lodgment on its
surface.