Interesting. This article is from USDA.gov and it lists temps of 140F, 160F, and 180F at 15 minutes. It says experimental so i don't know if these tests are safe or not.
Anyway, heres a link to the aticle. Its in PDF format.
https://www.ars.usda.gov/ARSUserFiles/60701000/Pickle%20Pubs/p15.pdf