Over
Laying
with
Mineral
Oil
Many
bacteria
and
fungi
can
be
preserved
by
covering
the
fresh
growth
in
agar
slants
with
sterile
mineral
oil.
The
oil
must
be
above
the
tip
of
the
slanted
surface.
The
method
is
very
simple
and
cell
viability
is
high
compared
to
frequent
transfer
and
storage
at
low
temperature.
Mineral
oil
covered
cultures
are
stored
at
room
temperature
or
preferably
at
0-5°C;
the
latter,
is
desirable.
Some
microorganisms
have
been
preserved
satisfactorily
for
more
than
15-20
years
by
this
method
