Method

Advantages

Disadvantages

Shelf Life

Subculture

1.  Easy to use

2.  Special equipment not required

1.  Reduced physiological actives

2.  Prone to variance

Six months under room temperature; 4°C for one year

Paraffin oil overlay

1.  Slow down metabolic reactions

2.  Simple activation steps

1.  Poor genetic stability

2.  Decreased long-term activity

More than one year

Sterile water suspension

1.  Easy to operate

2.  Simple activation steps

1.  Water easily evaporates.

2.  Suitable for short-term storage

Six months at 10~15°C half-year

Freeze-drying

1.  Easy to transport and sell

2.  Save space 

3.  High safety stability

1.  Limited applicable strains

4-10 years

Cryopreservation

1.  High safety stability

2.  Long shelf life

3.  Applicable for various strains

1.  Expensive equipment and supplies

2.  Ice crystal causes damage.

More than 4-5 years; up to 10 years for some strains