"Sammy" > wrote in message
...
> If cooking oil goes rancid in a container then would any oil poured
> into that same (unwashed) container go rancid more quickly?
>
> (1) I have the impression that a trace of rancid oil acts like a
> sort of catalyst for rancidity in non-rancid oil.

No, this is not true. Rancidity is the result of the oil reacting (slowly)
with oxygen in the air. A trace of old rancid oil will not hasten the
deterioration of new oil - but it will affect the flavor.

> (2) If the container were washed but the merest hint of oil rancid
> oil were left behind then is this sufficient to accelerate rancidity
> in any new oil?

As per above, no. A good washing will in any case remove all the old oil.


--
Peter Aitken

Remove the crap from my email address before using.