steam or other heated pipes. Food inspectors and warehouse personnel must be
constantly alert for evidence of damage, improper sanitation, spoilage, and insect or
rodent contamination so that immediate action can be taken to correct the situation and
prevent additional loss.
Storage time varies for different items. Length of storage for a given item is figured
from the date of pack, not from the date of receipt at a storage facility. Subsistence must
be grouped by item category and date of pack to aid in proper rotation of the stock, which
in an ideal environment is the most effective means of preventing deterioration, spoilage,
or attack by insects. The length of time a product can be stored is influenced by the
temperature, humidity, protection from the elements, condition of the product when it is
received, method of preservation used, condition and type of packing and packaging, and
the kind of handling it receives.
FACTORS AFFECTING STORAGE LIFE
TM 38-400, Joint Service Manual for Storage and Materials Handling, lists the
recommended approximate storage life for many semiperishable items stored under
optimum conditions. This list should be used as a guide by the inspector in determining
the shelf life of troop issue items. However, storage life becomes uncertain if the items
are subjected to high humidity, poor air circulation, or extremes in temperature. The
remaining storage life must always be based on a thorough inspection of the product.
There are three main causes for deterioration or spoilage of semiperishable subsistence:
a. Age. Food deterioration due to aging is a continuous process that begins at
harvest, slaughter, or manufacture and continues until the food is no longer serviceable.
Good preservation and storage techniques merely reduce the rate of this process.
b. Microorganisms. The growth of bacteria, yeast, and molds may cause the
production of gas, objectionable odors and flavors, and toxic substances. For example,
swelling in canned foods may result from microbial growth.
c. Environment. Freezing temperatures normally do not harm dry products, such
as grains, flour, sugar, starch, cereals, and dehydrated foods. However, products with
large amounts of water, such as canned goods, will freeze and possibly burst. Even if the
container does not rupture, the product inside may undergo changes in consistency and
texture. Emulsions that separate when frozen, such as mayonnaise and mustard, can be
recombined with the proper equipment. High temperatures are detrimental to canned
goods and greatly shorten the storage life of all subsistence because such temperatures
accelerate the natural deterioration. High temperatures also speed up chemical
reactions, such as oxidation and rancidity in fatty foods. The interaction between high
acid content subsistence and metal cans can cause pinholing, spangling, hydrogen