2 o6 
FLORIDA STATE HORTICULTURAL SOCIETY 
LETTUCE PRECOOLING AND HANDLING INVESTIGATIONS 
The lettuce investigations included a 
study of the methods of cutting and 
handling and the effect of precooling on 
carrying quality in transit and keeping 
quality after arrival on the market. 
The special method of cutting em¬ 
ployed consisted in removing the heads 
in such a way as to leave all of the 
lower leaves which touched the ground 
still attached to the roots. The object of 
this was to eliminate, as far as possible, 
infections of “lettuce dlrOp,” a, fungus 
disease which causes serious loss both in 
the field and also in transit and 
on the market. The 'fungus caus¬ 
ing this disease passes through unfavor¬ 
able seasons in the ground and usually 
first attacks the bottom of the lower 
leaves of the lettuce plant. By remov¬ 
ing these lower leaves it was possible to 
a large extent to keep these fungus in¬ 
fections out of the baskets, both those 
which appeared as distinct rots and those 
which were not yet noticeable to the 
ordinary observer. 
The precooling was done by means of 
the portable precooling plant of the Of¬ 
fice of Horticultural and Pomological 
Investigations, cold air being blown 
through the car after it was loaded and 
ready for shipment. The initial temper¬ 
ature of the lettuce, as determined by 
readings of electric thermometers placed 
at various points in the load, varied in 
different cars according to the weather 
conditions front about 50 degrees to 
slightly less than 70 degrees, while the 
final temperature at the end of the pre¬ 
cooling period averaged somewhat over 
41 degrees. 
The experimental work was carried on 
in the vegetable section in the vicinity of 
Palmetto, in Manatee County. From 
'this point experimental lots of lettuce 
were shipped in ordinary commercial cars 
to northern markets, where they were 
inspected by Bureau representatives as 
soon as the cars were unloaded and again 
three days later. The experimental series 
shipped in this way consisted - of two 
baskets each of carefully and commer¬ 
cially cut lettuce, comparable baskets of 
each being loaded in the top and bottom 
tiers in the car. Corresponding to each 
experimental shipment a comparable 
series was held in an iced refrigerator 
car in Palmetto, similar to the lots 
shipped except for the fact that fewer 
baskets of carefully and commercially 
cut lettuce were used, no comoarison be- 
ing made between top and bottom: tier 
conditions in the car. Corresponding to 
each precooled holding and shipping lot 
there was a comparable non-precooled lot 
held or shipped in an ordinary iced car. 
In the case of the holding lots the non- 
precooled baskets of lettuce were first 
placed near the roof of the car, then two 
days later brought about half way down, 
and finally, four days after loading, 
were placed on the floor of the car, the 
temperature being thus reduced gradu¬ 
ally and conditions brought about that 
corresponded as closely as possible with 
