Florida Agricultural Experiment Station


cised both in the selection of fruit to be artificially colored and
in the manner in which the coloring process is carried out. Al-
though the artificial coloring of fruit has an established place in
our citrus industry, it should be used as an aid in finishing the
natural coloring process rather than as a means of forcing a
color on immature fruit. To attempt the latter is but to court
trouble, as immature green fruit is difficult to color and liable to
develop more injury and decay than mature fruit. Before the
fruit is subjected to the coloring process it should at least show
some evidence of the breaking of the green color. Rind blem-
ishes, injuries, and patches of scale-insects cause differences in
colorability. Fruit that has been sprayed with oil emulsion
shortly before it is picked is not colored readily by the gas, since
the oily film inhibits respiration.
 Where ethylene gas is used, the dosage of gas and the ventila-
tion of the coloring room are especially important. Only the
standard dosage of 1 cubic foot of the gas to 5,000 cubic feet of
room space should be used every 6 or 8 hours in charging the
rooms. The fruit should not be crowded in the coloring room;
a space of at least 4 inches should be allowed between each tier
of boxes. Unless provision is made for constantly introducing
a small quantity of fresh air, as is done under the recently de-
vised "trickle system" of coloring, the rooms should be thorough-
ly ventilated for from a half hour to an hour before each gassing,
taking care to change the air completely. Poor ventilation not
only retards coloring but, in combination with high temperatures
and an excess of gas, may result in a surface pitting of the fruit
and an increase in decay. Excessive doses of ethylene gas also
retard coloring and may lead to rapid decay. Control of the tem-
perature and humidity is also extremely important. Too high
a temperature is likely to injure the fruit, while too low a tem-
perature will unduly prolong the coloring process. The tempera-
ture should be kept within the limits of 800 to 850F. A uniform
temperature will give the most satisfactory results. The relative
humidity should run about 80 to 85 percent.
 The fruit should not remain in the coloring room longer than
 72 hours. If it does not color within this period it is too green,
 even though it may pass the acid test. After the fruit has been
 colored, it is a good practice to precool it as quickly as possible
 in order to retard the development of decay.
 Packing in Relation to Decay:-Too much stress cannot be