3-12. PRESERVATION BY VINEGAR
The preservative action of vinegar is based upon its acetic acid content.
Pathogenic bacteria are rapidly destroyed in pickle solutions containing three percent acetic
acid and three and one-half percent salt. Vinegar is important as a preservative, because it
reduces the thermal death time of microorganisms and either inhibits or kills microorganisms,
depending on the concentration used.
3-13. PRESERVATION BY PICKLING AND FERMENTATION
The preservative action of pickling and fermentation is accomplished by utilizing
a. Pickling. In pickling, salts are combined with selected microorganisms in a
pickle solution. The vegetables are preserved and can be kept for a considerable
length of time, depending on factors such as temperature. An example of the
preservative action of pickling is seen in the difference between fresh cucumbers and
the end result, pickles.
b. Fermentation. There are two types of fermentation--alcoholic fermentation
and acid fermentation. Alcoholic fermentation is used to create alcohol by the
anaerobic decomposition of a carbohydrate by yeast to produce ethanol and carbon
dioxide. This process is used to produce beer. Acid fermentation is the anaerobic
decomposition of a carbohydrate food by microorganisms (or enzymes) to produce the
desired flavor and/or a more stable product by lowering the pH. This process is used to
produce cheeses and sauerkraut.
Section III. METHODS OF PRESERVATION--THERMAL METHODS
3-14. PRESERVATION BY SMOKING
a. Desirable Effects of Smoking. Smoking has been used for several
thousand years to preserve meat products. Smoking is rarely used alone any more to
preserve meats, but instead is used on cured meats. Some of the desirable effects of
smoking cured meats are as follows:
Brings out the color inside cured meats.
Has a drying effect.
(3) Impregnates the outside of the meat with constituents of the smoke that
serve as antiseptics and germicides.
Imparts desirable organoleptic properties.