Related for Pesachim 3:2
בָּצֵק שֶׁבְּסִדְקֵי עֲרֵבָה, אִם יֵשׁ כַּזַּיִת בְּמָקוֹם אֶחָד, חַיָּב לְבַעֵר. וְאִם לֹא, בָּטֵל בְּמִעוּטוֹ. וְכֵן לְעִנְיַן הַטֻּמְאָה, אִם מַקְפִּיד עָלָיו, חוֹצֵץ. וְאִם רוֹצֶה בְקִיּוּמוֹ, הֲרֵי הוּא כָעֲרֵבָה. בָּצֵק הַחֵרֵשׁ, אִם יֵשׁ כַּיּוֹצֵא בוֹ שֶׁהֶחֱמִיץ, הֲרֵי זֶה אָסוּר:
Dough in the cracks of an areivah (a kneading trough) [used to reinforce fragments and splits] — If there is an olive-size (of dough) in one spot, he must remove it. If not, it is neutralized by its smallness. [And if it is not used for reinforcement, even less than an olive-size must be removed, for he does not void it there (to the areivah), and he might decide to take it from there.] The same applies to uncleanliness (tumah). [If a sheretz touched this dough on Pesach ("whose prohibition gives it significance") — if there is an olive-size of dough, it acts as a partition against tumah (i.e., against tumah being imparted to the areivah). It is not considered as (part of) the areivah, and tumah is not transferred to it. With less than an olive-size — if he is not concerned about it, it is voided to the areivah; it is considered as if the sheretz had touched the areivah itself, and it becomes tamei.] If he is concerned about it (i.e., about its being there), it is a partition; and if he wants it there, it is like the areivah. [This is what is meant: And on the other days of the year, "when its prohibition does not give it significance," it depends not upon the size (of the dough), whether or not it is an olive-size, but upon his concern. If he is concerned about its being there and will eventually remove it from there, it is a partition against the (transference of the) tumah, whether or not it is an olive-size, and it does not confer tumah upon the areivah. And if he is not concerned about it and wishes it to remain there, even if it contains several olive-sizes, it is like part of the areivah, and when the sheretz touches the dough, it is as if it touches the areivah itself.] Batzek hacheresh ("deaf-mute" dough) [which when struck with the hand does not emit a sound, like a deaf-mute, who is called and does not answer. Another interpretation: "Batzek hacheress" ("shard dough") [which is as hard as a shard, so that it cannot be determined whether or not it has become chametz] — If there is aught like it which has become chametz, [i.e., if there is other dough which was kneaded at the same time as it was, and which has become chametz], it is forbidden, [and if there is not aught like it, then the standard (for its becoming chametz) is the amount of time it takes one to walk a mil at a normal pace, about two-fifths of an hour.]