Brazil nuts are harvested from wild trees growing in the Amazon River basin. Due to plant culture difficulties, there are very few brazil nut plantations.
The brazil nuts sold for export to the U.S. and other countries are brought to packing houses in Brazil. There the in-shell nuts are dried in automatic dryers to produce a moisture content of 11% (in-shell) or 6% (shelled), for shipment.
Nuts are shelled by soaking in water (salt water, usually) for 24 hours, then the nuts are boiled for 5 minutes. The boiling softens the shell, and makes cracking (by hand or machine) much easier. Nuts that are to be sold as blanched or sliced nuts, may be boiled again, before blanching and/or slicing.
Remarks: The heat from boiling will kill the nut and remove its viability. Shelled nuts are not sproutable.
Recommendations: shelled nuts are devitalized. Buy only in-shell, and shell manually (a tedious and difficult process) as needed.