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FOOD CANNING WASTE UTILIZATION
N. H. Sanborn
Research Chemist, National Canners Research Laboratory
Washington, D. C.
The preparation of fruits and vegetables for canning produces
in the aggregate an enormous volume of waste, both solid and liquid.
The disposal of these wastes, even by small canning plants, is fre¬
quently both difficult and expensive. The recent shortage and high
price of animal feed has focused attention on the possibilities of
utilizing cannery and other agricultural wastes although considerable
thought has been given to this problem at one time or another in an
effort to reduce disposal costs.
Most canners find that the disposal of liquid wastes resulting
from liquid wastes. Analyses show that they contain after screening
only 0.1 to 0.4 per cent total organic matter of which part is in solu¬
tion and the balance finely divided suspended material. Obviously
such low concentrations of plant material offer no possibility of utiliza¬
tion. In isolated cases and under special conditions some waste waters
have been used for irrigation. The re-use of water within the can¬
nery is impractical from a bacteriological standpoint if for no other
reason.
Solid wastes, on the other hand, could theoretically yield a large
quantity of usable by-products. That utilization has not been prac¬
ticed much more extensively is owing to: (1) the seasonal nature
of fruit and vegetable canning; (2) the perishable nature of the
waste which would require immediate conversion; (3) reluctance of
canners to assume additional responsibilities during the intensive can¬
ning season; and (4) the financial return would be comparatively
small since the by-products produced would enter highly competitive
markets. Most of these objections could be met by the establish¬
ment of separate waste utilization plants centrally located within
economic hauling distances from several canners and operated in
conjunction with other agricultural products. Alfalfa driers, for
example, could dry for feed purposes certain vegetable wastes. Be¬
cause of the long citrus fruit season and concentration of the in¬
dustry within small areas it has been found practical to operate
centrally located feed mills utilizing waste citrus peels.
The available cannery waste from some of the more important
vegetables and fruits and the per cent waste based on the condition
in which these vegetables and fruits are delivered to the cannery