Eating the mushrooms is making their meat radioactive, Jiri Drapal at the State Veterinary Administration told Reuters. "It is more or less a seasonal issue," Drapal said.
And due to the fact that the isotope stays radioactive for decades, the boars may be glowing for years to come.
The half life of Caesium 137 is 30 years - meaning it takes 30 years for the radioactivity of the isotope to fall to half its original value. Then another 30 to fall to half again, and so on.
"We can expect to find (affected) food for a number of years from now," Drapal said.
And that could cause some problems with the supply of boar meat, which is popular in the Czech Republic.
It often shows up on restaurant menus in goulash, a thick stew made from meat, sauce and dumplings.
Any boar that ends up as goulash ought to be safe, as not just boars, but any wild animal that is hunted, must be inspected before its meat can get to customers.
Radioactive meat is banned from circulation, Drapal said.
However, it isn't all good news - the bad news is that 614 animals were inspected from 2014 to 2016, and 47 percent were above the limit - almost half, which means that wild boar meat will be in short supply.
However, even meat from radioactive animals would be a health hazard only in large doses, Drapal said.
You would have to eat it several times a week for couple of months, to get sick, he added.