True regarding pasteurization is? (DNB June-12)
|A||A few sporing bacteria get killed by pasteurization|
|B||Milk is heated to 70 degree C and held for 30 minutes|
|C||Milk is rapidly cooled to zero degrees centigrade|
|D||It is done for checking milk-borne infections|
a. Tyndallization is a method of fractional sterilization. It is done for those media which are destroyed at 120°C.
b. In this process the medium is placed at 100°C in steam for 30 minutes on 3 successive days. This method is used for sterilization of egg and serum containing media.
c. The underlying principle is that the vegetative forms of bacteria are destroyed at 100°C while the bacterial spores survive. These spores germinate and are killed on subsequent heating.