For the source text click/tap here: Pesachim 76
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Levi said: That aroma does not cause meat to be forbidden. Even lean kosher meat that one roasted with fatty non-kosher meat is permitted. What is the reason for this halakha? Although the non-kosher meat emits an aroma that is absorbed into the kosher meat, it is merely an aroma, and an aroma is nothing significant.
This Halacha leads us to examine aromas and why the smell of treif might be forbidden, and what is the physiology of olfaction.