Halakhah for Tahorot 8:6
כְּלָל אָמְרוּ בַטָּהֳרוֹת, כֹּל הַמְיֻחָד לְאֹכֶל אָדָם, טָמֵא, עַד שֶׁיִּפָּסֵל מֵאֹכֶל הַכֶּלֶב. וְכֹל שֶׁאֵינוֹ מְיֻחָד לְאֹכֶל אָדָם, טָהוֹר, עַד שֶׁיְּיַחֲדֶנּוּ לְאָדָם. כֵּיצַד. גּוֹזָל שֶׁנָּפַל לְגַת וְחִשַּׁב עָלָיו לְהַעֲלוֹתוֹ לְנָכְרִי, טָמֵא. לְכֶלֶב, טָהוֹר. רַבִּי יוֹחָנָן בֶּן נוּרִי מְטַמֵּא. חִשַּׁב עָלָיו חֵרֵשׁ, שׁוֹטֶה וְקָטָן, טָהוֹר. אִם הֶעֱלָהוּ, טָמֵא, שֶׁיֵּשׁ לָהֶן מַעֲשֶׂה וְאֵין לָהֶן מַחֲשָׁבָה:
A rule was stated with regard to purities [of foods]: Anything which is designated for human consumption [if it becomes impure it] remains impure until it is rendered unfit for a dog to consume; and anything which is not designated for human consumption remains pure [and cannot be rendered impure] until one designates it for a human. How so? A fledgling which fell into a wine press, if one intended to take it out for a non-Jew [to eat], it is impure; if for a dog, it is pure. Rabbi Yochanan ben Nuri declares it impure [in either case]. If a deaf-mute, a fool, or a minor had the intention [to take it out, even for a non-Jew to eat], it is pure. If he took it out [for a non-Jew to eat], it is impure because these [categories of people] are capable of action but not of intention.