Related for Pesachim 2:8
אֵין נוֹתְנִין קֶמַח לְתוֹךְ הַחֲרֹסֶת אוֹ לְתוֹךְ הַחַרְדָּל, וְאִם נָתַן, יֹאכַל מִיָּד, וְרַבִּי מֵאִיר אוֹסֵר. אֵין מְבַשְּׁלִין אֶת הַפֶּסַח לֹא בְמַשְׁקִין וְלֹא בְמֵי פֵרוֹת, אֲבָל סָכִין וּמַטְבִּילִין אוֹתוֹ בָהֶן. מֵי תַשְׁמִישׁוֹ שֶׁל נַחְתּוֹם, יִשָּׁפְכוּ, מִפְּנֵי שֶׁהֵן מַחֲמִיצִין:
Flour is not to be put into charoseth [something containing vinegar and water, into which meat is dipped] or into mustard. And if one put it [into mustard], he must eat it immediately. [For mustard is sharp and it does not become chametz very quickly as it does in charoseth. But with charoseth, the first tanna concurs with R. Meir that it is forbidden.] R. Meir forbids it [even if he puts it into mustard, holding that it becomes chametz in mustard immediately, as in charoseth. The halachah is not in accordance with R. Meir. The Pesach (i.e., the meat of the Pesach offering) is not to be cooked, [it being written (Exodus 12:9): "…and cooked, cooked" — in any way], neither in liquids nor in fruit juices. But it may be anointed and dipped in them [after being roasted, and we do not say that its taste is thereby neutralized. Or else, even before it is roasted, it is permitted to anoint the Pesach with fruit juice. For thus was it taught (7:3): "If they anointed it with oil of terumah, if they were a company of Cohanim, they may eat it."] The water used by the baker [to cool his hands in when he forms the matzoth] should be spilled [down an incline, so that it not collect in one place] because it (thereby) becomes chametz.