Agriculture Reference
In-Depth Information
In the first case vegetables must be handled carefully, washed, and transported in
packing materials, which protect them from microorganisms and insects as well as
physical damage. Care during harvesting prevents or minimizes bruising and cuts,
which can lead to entry of microorganisms, which decompose the vegetable. In
addition these types of imperfections make the vegetable less appealing to the
buyer. Washing to remove soil, insecticides, and the like from vegetables will also
remove deleterious organisms, and, if cool water is used, will cool the vegetable
thus further extending its shelf life. Packing materials such as straw can protect veg-
etables from bruising during transport while keeping them cooler and protected from
the sun.
It is common to control the environment of vegetables to prolong their shelf life.
This can be as simple as keeping then moist or as complex as refrigeration and atmos-
pheric control. When vegetables are harvested, they begin to loose water, and thus the
quality begins to decline and make the vegetable less appealing to buyers and to sellers
if the sale is on a fresh weight basis. On a fresh weight percentage basis the nutrient
content increases. Applied moisture in hot, dry, and cold climates or while refrigerating
can significantly prolong the shelf life of vegetables. However, in hot humid climates
moisture, especially without refrigeration, can lead to increased degradation of veg-
etables. Refrigeration without freezing will increase shelf life of vegetables signifi-
cantly; not only does it retard the loss of water it also retards the growth of
microorganisms and inhibits insects.
The atmosphere surrounding the vegetables can be controlled by changing the ratios
of oxygen, nitrogen, and carbon dioxide in it. This requires two things; first the vegetable
must be in a container that will maintain the gas composition. Second, the gas compo-
sition must be tailored to the specific vegetable and the conditions under which it is har-
vested. This type of packaging and storage is used in developed countries but is not
generally available in developing countries. Note that while the vegetables packaged
this way are generally ready to eat they will cost significantly more.
Losses of vegetables can also be controlled by the use of various chemical means.
Chemicals can be used to either increase or decrease the rate of ripening or color devel-
opment. They can also be used to kill microorganisms that degrade the vegetables. One
way this is done is by fumigation with various chemicals in a closed container.
4.14
CONCLUSIONS
Vegetables are considered an essential part of any diet, but they generally do not
supply large amounts of nutrition. They are distributed widely throughout the world,
although some do have more restricted environmental needs. Cultivation of vegetables
is much the same as with other crop seeds planted in a prepared seedbed and weeded
as necessary. Unlike other crops, vegetables can be harvested at varying times and
even before maturity. Some vegetables have growth habits along the ground, or they
can be supported by trellises or other means. Although there is significant national
and international trade in vegetables, there are also important local and family
production and use.
