Question:
I had in the refrigerator a half an onion that was previously cut with a clean aino ben yomo meat knife. The onion was cut on a clean meat cutting board.
In haste, I grabbed that same onion days later and then cut the remainder of it with a clean ben yomo dairy knife on a clean (wood) dairy cutting board. The chopped onion got put with oil into a clean ben yomo dairy pot and was cooked with other pareve ingredients. A k'dei netilah of the cut surface was not removed prior to cooking, as the error was only discovered the following day.
What is the status of:
- the dairy knife
- the cutting board
- the dairy pot?
Many thanks for your guidance.
Answer:
Before addressing the question, we have to know that both the meaty and dairy knives were indeed used for hot meat and hot milk. If the milky knife wasn't actually used for hot milk or cheese, or if it was only used for kli sheini milchig, then things would be more lenient.
If the knives were indeed meaty and milky, then:
Regarding the pot- If there was less than 60 times the onion in the pot, then it needs kashering because the meaty onion became treif from the milky knife, and it was cooked inside it. Regarding the knife - it is the subject of a machlokes, some are lenient and some are say that it need hagalah, therefore it is preferable for you to kasher it
Regarding the cutting board - most poskim say that it is fine.
Sources:
Y:D 96-1, Shach 9, Pri Megadim M:Z O:CH 447-13, and Eshel Avrohom32, CHochmas Odom 49-10, Shut Chayei Halevi 5-62 (9), KOvetz M'bais Halevi Y:D pg 35 that R' Vozner zt"l said that we can be leineint about this, also see Ohel Yackov Siman 96 ftnt. 26-27 from R' Eliyashiv and other poskim to be meikel b'dieved with the cutting board.