Storage of Dry Milk
"Eat What You Store, and Store
What you Eat."
Types of Nonfat Dry Milk
Regular and instant nonfat dry milk are made from skim milk that
has been dried by spraying into hot air. Instant milk is regular milk which has been
further processed causing it to clump together which results in a product that is easier
to reconstitute with water than is regular nonfat dry milk. They both have the same
nutrient composition. Regular nonfat dry milk is more compact and will require less
storage space, however, it is harder to reconstitute. The most common type of dried milk
to be found in grocery stores is instant nonfat dry milk. Dried whole milk may also be
available, however because of the fat present, it will not store as well as nonfat dry
milk. Dried buttermilk is available to be used in recipes calling for buttermilk. It will
not keep quite as long as nonfat dried milk since is has a slightly higher fat level.
Things to consider
when buying dried milk: 1. It is best to buy dry milk fortified with vitamins A and D. 2.
A claim of "No Preservatives" may be on the label to reassure customers,
however, added preservatives are not legal therefore no dried milk processed in the U. S.
will contain preservatives. 3. The label may say Grade A to indicate the quality of the
milk used in the drying process. Essentially all processing plants producing dried milk
use Grade A milk today. 4. "Extra Grade" on the label indicates that the
processing plant has met certain criteria and the milk is slightly lower in butterfat and
moisture content, more soluble, contains fewer bacteria, and contains fewer scorched
particles. 5. The size of the container holding the dried milk should fit storage space
considerations and family need. Once a container is opened, the milk will not keep as
long, therefore, a very large container is not desirable for a household that consumes a
small amount of milk per week. 6. Type of package becomes important if the dried milk is
to be stored for long periods of time. The package should be water proof and impermeable
to air. Plastic films are good protection against oxygen over short periods of time, but
not if the dried milk is to be stored for more than a year. 7. Do not buy more dried milk
than you would normally use in a reasonable time period. 8. Date the milk when you buy it.
Storage Conditions
- Temperature—The storage
temperature is the most important factor in determining the length of time that dried milk
can be stored and should be as cool as possible.
- Oxygen— Exclude oxygen as much as
possible to decrease the speed of undesirable chemical changes. Dried milk canned with
nitrogen or carbon dioxide to replace air (which contains oxygen) will keep longer than
dried milk that is exposed to air. Vacuum canning also decreases the available oxygen.
- Packaging— The packaging for milk
which will be held for extended periods of time should not permit air nor water vapor into
the package. Cardboard and polyfilm packages do not provide as good of a barrier to air as
do metal cans.
- Moisture— Moisture will cause
caking and accelerate undesirable changes in flavor, therefore, if the milk is not
packaged in cans, store it in a dry location.
- Light— Most types of packaging
will block out light. If dried milk is to be stored in a package type (ex. glass jars,
plastic bags) which does not do so, store it in a dark place. Light will accelerate the
undesirable chemical changes in flavor and odor. The following storage times and
temperatures are based on nonfat dry milk (instant or regular) stored at different
temperatures and in unopened packages with either nitrogen or carbon dioxide to replace
the air in the package.
Storage times will be shorter for products stored in paper or cardboard packages.
50 F 48 months
70 F 24 months
90 F 3 months
Use of Nonfat Dry Milk
Reconstitute instant nonfat dry milk by mixing or shaking the
dried milk with enough water for the desired yield. To disperse regular nonfat dry milk,
beat dried milk with about half the water until uniform, then add enough water to reach
the desired yield.
After
reconstitution, the dry milk should be stored in the refrigerator. Many individuals find
it desirable to mix equal amounts of reconstituted dry milk and fresh milk for drinking
purposes. The resulting drink is highly acceptable as well as economical. It is much more
desirable to rotate your supply of dried milk by using the oldest first than to have milk
with off-flavors. However, if you do have milk which has been stored too long and has
developed some off-flavor, it can best be covered up by using in baked products like quick
breads or in mashed potatoes. Off-flavors are more obvious in products which use more milk
such as yogurt, puddings, and gravy.
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