Responsa for Chullin 215:22
דאיתמר רב ורבי חנינא ורבי יוחנן דאמרי
extracted it becomes permitted.<span class="x" onmousemove="('comment',' The contention is that when a substance, rendered forbidden because it had absorbed the essence of a forbidden matter, is cooked together with other permitted food, the forbidden essence is considered as extracted from the original substance and distributed equally among the contents of the pot; so that if there is enough in the Pot to neutralize the quantity of forbidden essence it will all be permitted, even the original substance which Was rendered forbidden. In other words the substance, which is forbidden because of the forbidden essence that it absorbed, is not regarded as nebelah and forbidden absolutely for all time, but it is even possible for it to become permitted once again when cooked with other substances.');"><sup>17</sup></span>
Teshuvot Maharam
A. In France I witnessed a great controversy over this matter. But, at the time, I failed to inquire into the reasons of both those who permitted and those who forbade the use of the pot and its contents. I also discovered that Ri forbade the use of the pot and its contents, probably for the reason that the drop of milk first rendered the pot unfit for use, and the pot, in turn, rendered its contents unfit for use.
SOURCES: L. 121. Cf. Mord., Hulin, 679; P. 515; Hag. Maim., Maakalot Asurot 9, 3; Asher, Responsa 20, 26; Sefer Haparnes 19.