S-Newsleter-T-.19


Citrus Station Mimeo Report CES 69-17
December 12, 1968
650-WG-Lake Alfred, Florida


UNIVERSITY OF FLORIDA INSTITUTE OF.FOOD AND AGRICULTURAL SCIENCES
and
FLORIDA CITRUS COMMISSION


Packinghouse


NewftIter


Harvesting and Handling Section
University of Florida
Citrus Experiment Station
P.O. Box 1088
Lake Alfred, Florida, 33850


(Complimentary to members of the Florida Fresh Citrus Shippers Association.
Others wishing to receive this newsletter, send a dozen stamped preaddressed
envelopes to the above address.).






-Newsletter No. 19 (*-*)
Citrus Station Mimeo Report CES 69-17
December 12, 1968
650-WG-Lake Alfred, Florida

Harvesting and Handling Section

PACKINGHOUSE NEWSLETTER


ETHYLENE EXPLOSION HAZARD

We regret to hear of a serious accident in which several packinghouse workers
were injured in an ethylene explosion. We have been asked whether special pre-
cautions (such as "No Smoking" signs) are necessary in degreening rooms. There is
absolutely no hazard from normal degreening concentrations, for which we recommend
using ethylene at 1 to 5 parts per million. Ethylene is explosive in concentra-
tions of 3 to 34 percent in air. This lower limit of 3 percent is 30,000 parts
per million or 6,000 times more ethylene than the maximum that we recommend for
degreening.

However, ethylene is an explosive gas comparable to natural gas, "L.P." gas,
and others used for fuel purposes, in kitchens, laboratories, and commercial estab-
lishments. When ethylene lines are suspected of leaking, all open flames should
be put out and electrical equipment that may spark should be turned off. DETECT
ETHYLENE LEAKS BY PAINTING JOINTS, VALVES, ETC. WITH DILUTE SOAP SOLUTION, NOT BY
USING AN OPEN FLAME.

One more point: ethylene trickle units are often filled with white mineral
oil, rather than water, as this remains clear and does not cloud with rust or algae.
Such mineral oil is safe and non-volatile. Do not confuse this with "mineral
spirits" which is almost as inflammable as gasoline.


FRUIT PICKED DURING THE SHIPPING HOLIDAY

The last paragraph of the Growers Administrative Committee release for
December 3, 1968 (dealing with the December 22 to 30 shipping holiday) states:

"According to the definition of 'prepare for market' given in the
agreement and order, the fruit may be picked and brought into the pack-
inghouse and gassed or left in the field boxes without being considered
as 'prepared for market,' and therefore would be eligible for shipment
after the termination of the holiday period if not carried beyond this
point in the normal preparation of the fruit for shipment."

Attention is drawn to the fact that holding such picked, unwashed fruit under
dry conditions can lead to subsequent disastrous losses from decay. The following
table shows the effect, in a typical experiment, of 48 hours or less under drying
conditions.








Newsletter No. 19 December 12, 1968

Effect of delayed handling on decay potential of 'Valencia' oranges held at 70F
(210C) after packing.a


% decay at 2 weeks
Treatment from picking
Processed immediately 3.8
48 hours on packing-
house floor 12.5
44 hours delays
outdoors 47.5
aFrom Hopkins and McCornack 1960, Proc. Fla.
State Hort. Soc. 73:263-269.

"Processed" = washed, waxed, packed in cartons.

"Outdoors" = 22 hours on truck bed and 22 hours
in shade of a tree.

If such "non-prepared fruit" is to be held, subsequent decay can be greatly
reduced by holding under humid (but not wet) conditions. Keep in a degreening
room with the room closed, fan on, steam or water for high humidity, but heat
and ethylene turned off as soon as the fruit is degreened.

Even with such precautions, we do not advise holding non-waxed fruit for
more than 2 or 3 days longer than the time necessary for normal handling and
degreening.


AVAILABLE PUBLICATIONS

"Consumer Packaging of Citrus Fruits," by W. Grierson, a ten-page reprint
from the 1968 Yearbook of the Produce Packaging and Marketing Association.

From Superintendent of Documents, U. S. Government Printing Office, Wash-
ington, D. C., 20402, at a price of $1.00, Agriculture Handbook 66 entitled, "The
Commercial Storage of Fruits, Vegetables and Florist and Nursery Stocks." This
handbook contains a wealth of information on essential storage requirements for
fresh fruits and vegetables.