[Avodah] Forms of Bitul

[Chana Luntz]

R Micha Berger wrote:
>> Becuase if so, then the stuff the centrifuge brought to the
>> top isn't actually "milk", from a halachic perspective.

And inter alia I replied:
> That is what I would suspect.  Ie if initially you are able to
> recognise it, then this is prior to the bitul happening.  Once bitul
> has happened, I believe the language used by the various rishonim is
> that it is "keino".  I don't know that they contemplate somebody being
> able to centrifuge the mixture to thereby re-separate what has
> previously been mixed and undetectable by our taste test.  

Further though to my earlier post because otherwise it might be misleading
- there is of course the concept of hozer v'niur, which kind of does
what you are looking for. Ie if a drop of milk falls into the meat stew,
and is batel, but then subsequently more milk falls in, the milk that
fell in first is added to the shiur of the milk that falls in next,
and at the point that all the milk that has fallen into the meat stew
adds up to more than sixty of the meat stew, the mixture becomes assur.
This is despite the very last drop that fell in being much less than
sixty. But at that point, the taste of the mixture, which has been
edging towards milky, finally hits it - ie your theoretical non Jew at
that point could detect the milky taste in the stew. That is not really
the same as having the same amount of milk which was determined to be
batel become not batel by modern chemical methods or centrifuge.

There is also additionally the Rema in Yoreh Deah siman 98 si'if 4 who
not only requires the removal of the milk that is obvious on the face
of the meat stew, but the addition of cold water, so as to cause the
milk that has fallen into the meat to rise to the top and enable it to
be identified and removed. Is this the equivalent of using centrifuge or
modern scientific methods to enable a separation? Now that we have these
modern methods, are we mechuyav to invoke them (even sending the mixture
to the lab if necessary) rather than rely on bitul? My inclination is no,
as I indicated above, and that this requirement of the Rema is really
just a chumra (as seems to be the language of at least of the meforshim),
and not mikar hadin (given that the consensus is that we cannot rely on
this l'kula, ie if there is less than sixty), and that we are certainly
not expected to take this further than that and effectively undermine the
whole concept of such bitul. Because surely with our scientific advances,
we would end up with a situation where every case of min shebaino mino
is ultimately separatable in the lab (probably at huge cost, but that
isn't the point) and therefore arguably the din of bitul b'shishim for
min shebaino mino no longer exists. It seems to me, however, that you
have to draw a line between what is reasonably possible for your average
Jew throughout the ages and what may now be possible in the lab given
our scientific advances.

Regards
Chana