Mishnah Machshirin 6:1: [If] one takes his fruit up to the roof because of the worms, and dew falls on them that does not achieve BeKhi Yutan. If he intended that [to happen] it does achieve BeKhi Yutan. [If] a deaf-mute, [or] an imbecile, or a minor took them up they [the fruit] do not achieve BeKhi Yutan even if he hoped that dew would fall on them, because they can act but they have no intention.

הַמַּעֲלֶה פֵרוֹתָיו לַגַּג מִפְּנֵי הַכְּנִימָה, וְיָרַד עֲלֵיהֶם טַל, אֵינָם בְּכִי יֻתַּן. אִם נִתְכַּוֵּן לְכָךְ, הֲרֵי זֶה בְכִי יֻתַּן. הֶעֱלָן חֵרֵשׁ, שׁוֹטֶה וְקָטָן, אַף עַל פִּי שֶׁחִשַּׁב שֶׁיֵּרֵד עֲלֵיהֶן הַטַּל, אֵינָן בְּכִי יֻתַּן, שֶׁיֶּשׁ לָהֶן מַעֲשֶׂה וְאֵין לָהֶן מַחֲשָׁבָה:

Mishnah Machshirin 6:2: [If] one brought up bundles [of vegetables] or prepared figs, or garlic to the roof for them to get damp that does not achieve BeKhi Yutan. All the bundles [of vegetables] in the market are impure. Rabbi Yehudah deems fresh [vegetables] pure. Rabbi Meir said: Why did they deem them impure? Is it not because of the moisture from the mouth? All [types of] flour and fine flour in the market are impure. Grains of wheat split into two pieces, into three pieces, and into four pieces are impure in all places.

הַמַּעֲלֶה אֶת הָאֲגֻדּוֹת וְאֶת הַקְּצִיעוֹת וְאֶת הַשּׁוּם לַגַּג בִּשְׁבִיל שֶׁיַּמְתִּינוּ, אֵינָן בְּכִי יֻתַּן. כָּל הָאֲגֻדּוֹת שֶׁל בֵּית הַשְּׁוָקִים, טְמֵאִין. רַבִּי יְהוּדָה מְטַהֵר בַּלַּחִים. אָמַר רַבִּי מֵאִיר, וְכִי מִפְּנֵי מָה טִמְּאוּ, אֶלָּא מִפְּנֵי מַשְׁקֵה הַפֶּה. כָּל הַקְּמָחִין וְהַסְּלָתוֹת שֶׁל בֵּית הַשְּׁוָקִים, טְמֵאִים. הַחִילְקָה, הַטְּרָגִיס וְהַטִּסְגִי, טְמֵאִים בְּכָל מָקוֹם: