According to a letter from Rav Moshe Vaye, author of the
sefer Bedikas Hamozon Kehalocho, which appeared in the
Hebrew Yated Ne'eman on 23 Teves, there is currently
a problem of worms (fruit fly larvae) in citrus fruits --
oranges, tangerines, grapefruits, etc. -- growing in Eretz
Yisroel. He attributes this problem (which is rare during the
winter) to the unusually warm weather. The worms are white,
with a small black dot on their head. Their size varies from
1 mm. to 1 cm.
When the worms are big, they are readily visible in the flesh
of the fruit, which also becomes soft and mushy. When they
are still small they are hard to detect. However, when the
fruit is juiced, the worms can be seen floating in the
juice.
Therefore, it is advised to squeeze the juice out of 2 or 3
fruits from each batch of fruits purchased, pour the juice
into a see-through glass, and examine it. If worms are found
in the juice, that batch of fruit should be used only for
juice, which should be strained.
There is an alternate way of checking oranges. Peel off the
orange skip of the peel, leaving the white skin below it on.
Check the white. If you find a small hole or a stain, cut
deeply into the orange at that point and look for worms. If a
fruit has been found to be infested, it should not be
eaten.
