> Did you bother to read your reference? Do you understand it? I did, and I
> see no reference to trace quantities of rancid oil hastening the
> deterioration of new oil.

Although its not written in this article, it is basic organic chemistry-
radical reactions (like the one when oils go rancid) start faster when a
radical starter (like rancid oil) is present.

http://www.meta-synthesis.com/webboo...l/radical.html