Most produce exported from Israel does not have tithes separated. If one knows that fresh Israeli produce or herbs have been purchased the following procedure, as formulated by the Chason Ish, must be followed prior to consumption:
Procedure for Separating Trumos and Maasros (Tithes)
Take one penny.
Remove slightly more than one percent of each type of produce (two types of oranges are counted as one type of fruit. A date and an orange are two separate types. Oregano, rosemary, thyme, etc are all different types of produce).
The more than one percent on the northern side of the separated portion is Trumah Gedolah.
The one percent left in the separated portion plus nine equal portions on the northern side of the produce is Maaser Rishon.
The one percent of Maaser Rishon will become Trumos Maaser.
Ten percent of the remaining separated produce will be either Maaser Sheni or Maaser Oni. If it is Maaser Sheni, it is to be redeemed by one prutah’s worth of this coin.
The coin can be used numerous times for further separations. The separated produce cannot be used for any reason. It must be wrapped in a proper manner and disposed of in a proper manner (ie, do not treat it like common trash but do not use it in any way.)