Removal Unnecessary?

Kalman from Telzstone asks:

My wife is cooking for our son’s bar-mitzvah, which will take place
in the middle of Ellul. She is using a number of kedushas shvi’is
ingredients, including potatoes. She intends to freeze the food and serve it
at the bar-mitzvah seudah (meal). I noticed that the bi’ur
period for potatoes starts on 15 Av. What do I have to do with our frozen
potatoes?

The bi’ur period for potatoes starts on 15 Av, but
only ends on 15 Cheshvan 5762. This means that potatoes must be declared hefker
on 15 Av, but not reacquired till 15 Cheshvan. If a person only has a small
amount of produce, he is exempt from bi’ur. The amount is enough for
three meals for each member of his household. Thus, if the amount of potatoes
you had frozen did not exceed the total quantity eaten by your entire family
(who live with you) in three meals, there would be no need to perform bi’ur.
However, since I assume you are preparing a sumptuous meal for a large number of
guests, bi’ur will be required. On 15 Av, you will have to take the
potatoes out of the freezer and declare them hefker in the street in
front of three people (choose really good friends!). You can then take them
inside and put them back in the freezer. However, you should make sure you do
not have the intention to reacquire them. Your bar-mitzvah guests can then enjoy
your wife’s delicious (hefker) potatoes!