Who loses the חזקת כשרות and what the suspicion carries with it: eating at his table, entrusting him with food, the fear of a swap, the special statuses (מסור, מומר, אנוסים) and the seller of forbidden food (Shulchan Aroukh, Yoreh De'ah 119 — 20 seifim)
החשוד לאכול דברים האסורים בין אם הוא חשוד באיסור תורה בין אם הוא חשוד באיסור דרבנן אין לסמוך עליו בהם ואם נתארח עמו לא יאכל משלו מדברים שהוא חשוד עליהם:
One who is suspected of eating forbidden things — whether he is suspected on a Torah prohibition or on a rabbinic prohibition — is not relied upon in those things; and if one has been hosted by him, one does not eat of his own food in the matters he is suspected of.
Shulchan Aroukh, Yoreh De'ah 119:1LEVEL 01
The Hebrew text of the 20 seifim with a fluent English translation. The ḥashud and the חזקת כשרות, eating at his table, entrusting him with food, the reach of the suspicion, the special statuses (מסור, מומר, אנוסים) and the seller of forbidden food, explained step by step.
📖 StudyLEVEL 02
In-depth pilpul: the ma'hloket ש״ך ס״ק א / ט״ז ס״ק ב on the חזקת כשרות of people in our day, the yesod of חשד (targeted or contagious), the difference between his own food and another's (seifim 7-8), and the yesod of חילוף (seifim 3, 19, 20).
📖 StudyLEVEL 03
Comparative tables (the perimeter of the suspicion, the special statuses, restitution and sanction), golden rules, the חשוד mnemonic, classic pitfalls and a line-by-line recap of the 20 seifim.
📖 StudyLEVEL 04
Practical halakha according to the ש״ך, the ט״ז and the פתחי תשובה, applied to purchases, invitations, kitchen staff and supervision. Note: the Admour HaZaken wrote no Shulchan Aroukh on Yoreh De'ah — this is a level of psak, not “Daat HaRav”.
📖 StudyAccording to the Shulchan Aroukh (YD 119:1), one suspected of eating forbidden things — whether a Torah prohibition or a rabbinic one — «אין לסמוך עליו בהם», and as his guest one does not eat of his own food in the matters he is suspected of. But the starting point remains the חזקת כשרות: the Shach writes that apart from an established ḥashud, every person is presumed kosher enough to eat with him (ש״ך יו״ד קי״ט ס״ק א). The Rama adds a וי״א: even from one not known as מוחזק בכשרות, «אסור לקנות ממנו יין או שאר דברי׳ שיש לחוש לאיסור» — yet he himself concludes «מיהו אם נתארח אצלו אוכל עמו»; and the Taz (ס״ק ב) upholds that stringency. For the application to your own situation, consult your Rav.
The Mehaber distinguishes (seif 2): if he is not suspected of eating forbidden food but only of selling it — «מתארח אצלו ואוכל עמו», and what he sends to his own home is permitted, since there is a חזקה that he sends of what he himself eats. The Shach gives the reasoning in the name of Rashi and the Ran: he is careless about לפני עור, but he himself eats no forbidden food (ש״ך יו״ד קי״ט ס״ק ה). The Rama adds: «עובר עבירה לתיאבון לא מקרי חשוד» — and the Shach specifies that he is ḥashud only if he would choose the forbidden while the permitted lies before him (ש״ך יו״ד קי״ט ס״ק ו). For the application to your own situation, consult your Rav.
Yes, according to seif 3: one gives him one's own food to prepare or cook without fearing a swap, «כיון שאינו חשוד על הגזל». The exception is one who has a stake in my welfare: the mother-in-law, «שבושה מחתנה ורוצה בתקנת בתה», and the innkeeper who is ashamed before her guest — there we fear she would swap bad for good. The Rama adds that a plain deposit, to be returned as it was, remains permitted. For the application to your own situation, consult your Rav.
No: «החשוד לדבר אחד אינו חשוד לדברים אחרים» (seif 4). There are only two extensions: whatever serves that prohibition — the butcher who drew the children with nuts, who is penalized down to selling nuts (seif 4; ט״ז יו״ד קי״ט ס״ק ז) — and the prohibition lighter in punishment (seif 5), unless the public takes the latter more seriously. And if he had been cleared of two suspicions and falls back on one of them, we fear for both (seif 6). Finally, regarding another person's food he remains נאמן even about that prohibition (seif 7), whereas about his own he is not, even under oath (seif 8). For the application to your own situation, consult your Rav.
According to seif 13: known before it was eaten, the buyer returns the goods and the seller returns the money; known after, «מה שאכל אכל והוא יחזיר לו הדמים» — a קנס, the Shach specifies (ס״ק כ״ה). Resold to a non-Jew or thrown to the dogs: «ישלם לו דמי טריפה». For a rabbinic prohibition, or where the produce is still intact, he returns the produce and takes back his money. And seif 15 adds the sanction: «המוכר דברים האסורים מעבירים אותו ומשמתים אותו», with no תקנה until he goes where he is unknown and willingly gives up money there, «כיון שאינו חס על ממונו». For the application to your own situation, consult your Rav.