Frei, who once pronounced the forged "Hitler Diaries" to be genuine, probably introduced the pollen grains himself or was duped and innocently picked up pollen grains another pious fraud had introduced (Nickell).
Danin and his colleague Uri Baruch also claim that they found impressions of flowers on the shroud and that those flowers could only come from Israel.
A weight of 20th century carbon equaling nearly two times the weight of the Shroud carbon itself would be required to change a 1st century date to the 14th century (see It may interest skeptics to know that many people of faith believe that there is scientific evidence which supports their belief in the shroud's authenticity.
Of course, the evidence is limited almost exclusively to pointing out facts that would be true the shroud were authentic.
For his work, Mc Crone was awarded the American Chemical Society's Award in Analytical Chemistry in 2000.