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Asexual reproduction in algae is shown (ii) Some algae forms also release toxins
by the process of binary fission or spore that are hazardous to other life forms.
formation. FOOD PRESERVATION
Definition : It is a process of treatment of food
so as to slow down the food spoilage by
bacteria, fungi and other microbes.
Requirement of food preservation : As we
-
know micro organisms are omnipresent. They
can spoil our food and thus can lead to various
food and water borne diseases. To prevent
these diseases proper preservation of food
and purification of water is desired as well as
Spore formation in algae required.
Methods of food preservation :
(a) Drying : Drying aims at reduction of
water content. As moisture is a very
favourable agent to promote microbial
growth so its reduction automatically
suppresses microbial growth and
Binary fission in spirogyra activity.
(b) Low temperature : Metabolic activities
Algae as a friend
are retarded at low temperature. As a
(i) They are a rich source of minerals.
Some of the algae are the richest result of which growth and reproduction
source of copper. of microbes is retarded and enzymatic
activities are also reduced. Temperature
(ii) Algae can be eaten directly as food.
e.g., Spirogyra is consumed in South can be reduced by storage of food items
India. in either of the following :
(iii) “Agar” is one of the most important Refrigerator (40- 70°C )
substances obtained from red algae. Cold storage (10-40°C )
(iv) Agar is an important ingredient of Freezer ( > 0°C )
microbial food i.e. used in the (c) High temperature : As all the living
laboratories.
organisms have the sustainable
Algae as a foe temperature so do microbes. If
(i) “Eutrophication” i.e. growth of algae temperature is raised above the
over the water body can block the sun suitable temperature that they can
rays from reaching the plants and
sustain, they will be killed and
animals that live under water. Thus, it
destroyed. But all microbes have
can lead to their death in deficiency of
different sustainability temperature.
resources.
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