“COMMON CARRIERS” 
EAT, Muck, Humus, Charcoal, Fuller’s Earth, 
Agar-Agar, etc., are some of the “carriers” used in 
preparing cultures artificially. 
Inoculating organisms, usually in liquid form, are 
placed in or on the “carrier” material. This liquid 
may contain enormous numbers of the organisms 
in suspension, or may contain only a small number 
of them, which by contact with the food materials 
in the containers, may grow and multiply to large 
numbers. Commercial Inoculants prepared in the 
above manner are perishable. 
DATING CULTURES 
{"COMMERCIAL concerns usually place a date on 
their containers, stating the length of time in 
which the cultures may be of use, or when prepared. 
Some of these cultures are at their highest efficiency 
for only a short period. Others may continue to 
grow and multiply at a rapid rate in the container 
until their food supply is used up and then die off 
because of lack of food. 
The large amounts of liquid used in the prepara¬ 
tion of some cultures favor the growth of certain 
types of molds, which may be present in the “car¬ 
riers” used. This high percentage of moisture, to 
allow for uncontrolled drying out in the “carrier” 
while on the dealers’ shelves, may not allow the or¬ 
ganisms to remain at their highest efficiency for an 
entire season. Thus, conditions for deterioration 
and spoilage are present. 
Seedsmen should occasionally examine samples of 
stock cultures. Molds and other fungi may have 
developed. Whether the presence of molds in the 
“carrier” is harmful or not, is beside the point. 
Ordinarily the customer associates molds with 
spoilage and this alone may make the culture unsal¬ 
able. When this condition exists, the culture should 
be withdrawn from sale and returned to the manu¬ 
facturer. 
It should therefore be noted that the “Method of 
Preparation”, “Selection of Strains”, “Carrier”, and 
even the “Containers” themselves have a very close 
relation to the period of effectiveness of the culture 
