Imperial Valley press., 1929-11-21
GRAPEFRUIT IS
''S;ii S7ERIiizED RI Hzi1 B BY
HEAT PROCESS


flee from Washington, the use of
heat sterilization for Florida grape
fruit as a condition of interstate
movement is authorized in connec-
ton with packing houses in that
state. Administrative instructions
amending the quarantine on ac-
count of the Mediterranean fluit
fly to this extent were issued Oe-
tober % by Secretary Hyde of tn
L. s. department Of agriculture.
This method of protecting citrus
fruit from the possibility Of being
a means of spreading the Msditer-
ranean fruit fly is one Of the i'm.
pcrtant developments which have
resulted from the research of the
department of agriculture in con-
nection with the fruit fly problem
/ and may have far-reaching useful
ness in the handling Of fruit. 1his
method has already been given
practical application in the treat
ment and marketing of some 20 ear
loads Of fruit, and fruit thus treat
ed has been sold at normal, includ
ing top, prices in northern markets.
Neither this nor any other method
of sterilizing host fruits and vege
tables from Florida is being given
70 infested fruit or vegetables. All
fruits or vegetables in infested
blocks are excluded from CONNER
| cial shipment or other movement
and are promptly destroyed. Steri-
lization is merely an additional pre-
caution over orchard and packing
house inspection to eliminate any
residual risk of spread of the pest.
The authorization Of this method
Of sterilizing grapefruit was in re-
sl.onse to the earnest request Of
growers, packers, and shippers cen.
cerned.
The following is the method Of
sterilizing grapefruit by heat which
has been authorized:
Heating, in connection with the
usual coloring process, the. fruit 20
a temperature of ITO degrees F. or
above (not to exceed lis degrees)
in the approximate center, Of the
fruit and holding the temperature
of 110 degrees or above (not to ex-
eeed 115 degrees) for a period of
eight hours.
No specifications as to the exact
methods and equipments for obtain
ing these conditions are prescribed.
Available information clearly indi-
Gates that by the application of dry
heat the required temperatures can
not be reached without injury to
the fruit. To prevent such injury it
is necessary to maintain a very high
humidity throughout the period of
treatment. In the tests where sue
cessful performance was obtained,
live steam as the source of heat
was applied in such a way as to se-
cure as. nearly as possible uniform
distribution of steam-heated air SO
directed as not TO discharge direct
ly on the fruit. In these tests the
eoloring was followed by the appli-
cation of the high temperature
necessary for sterilization. The air
temperature ranged from lis de-
grees to 116 degrees +. and the air
was very moist, SO that the hu-
nudity was practically 100 per cent.
The fruit was held in field boxes
stacked four boxes high with mar.
row aisles between, and without spe-
cial means Of separating the boxes
in each stack.
While the results Of the expert
ments so far conducted have been
successful, it should be emphasized
that inexactness and carelessness in
operation may result in injury to
fruit. On the other hand, available
information indicates that the fruit
will not be injured at temperatures
slightly higher than ITO degrees. In
authorizing the movement Of fruit
steriliZed in accordance with the
above requirements, it is to be un-
derstood that the department does
not assume responsibility for fruit
injury.