> Korean Fermented Foods >Stories of Microorganisms
>Kimchi and Microorganisms
Studies on Kimchi have been actively performed since the
middle of 1990’s.
In Kimchi made recently, general bacteria propagate rapidly
at the maximum rate of 10 times and again die out speedily.
The reason is that the rapid propagation of bacteria makes
carbon dioxide saturated where the bacteria cannot live
anymore, so in that situation, only the lactic acid bacteria,
the anaerobic microorganisms that can live without the air
start their action in it. The lactic acid bacteria gradually
ripen the Chinese cabbage or radish to be Kimchi as making
lactic acid with sour taste. This situation allows only
the lactic acid bacteria to be alive, and they make antibiotics
called ‘Bacteriocin’ which stops the growth
of other microorganisms.
The kinds of lactic acid bacteria exist differently according
to the ripening degrees of Kimchi, so the lactic acid bacteria
(cocci) exist in Kimchi ripened properly and the lactic
acid bacteria (bacilli) exist mainly in Kimchi ripened more.
The cocci produce several organic materials such as the
lactic acid and ethanol in particular, and the bacilli generate
mainly the lactic acid, so Kimchi getting sourer as it is
ripened is resulted from the latter.
There exist one billion to ten billion lactic bacteria
in 1㎖ of Kimchi at maximum. However, as the sour
taste gets stronger, even the lactic bacteria cannot get
used to it and die out, so at this time, yeast starts to
propagate, which causes the stale smell in old Kimchi.