Someone cut cold meat with a knife. They then washed it off (without making ne’itzah) and then cut an onion, does the onion become fleishig? What’s the din b’dieved?
Answer:
If the knife was new — it has never been used for hot meat — and it was clean after washing, the onion will remain parev.
Although the general assumption of poskim is that knives are generally “dirty” (because of fat that remains on them) it is fairly clear that in our times, knives (after being washed) are generally clean.
The knife can also be checked after cutting: If it is dirty (has residual fat on it), the onion will be meaty. If it is clean, and the knife does not have any beliyos of meat — it was never used for hot meaty items — the onion will remain parev.
In this context see Maadanei Asher (1:45), who writes that the halachic assumption that knives are dirty does not apply today.
