Can you please offer some guidance on the following case?
A clean, aino-ben-yomo dairy knife (might have been used to cut a kli rishon dairy quiche a while ago, but not sure) was used to cut zucchini for a pareve dish. Most of the zucchini was used for the pareve food, but there are a few leftover pieces. May those leftover pieces of zucchini be used l’chatchila for a chicken soup?
Involved in the same question, (the zucchini seems to be a machlokes between the Shach and Taz in S”A 89 by a dairy knife used to cut bread for dairy) are we lenient regarding the question of residue remaining on knives today if washing (or kinuach) was done?
Let’s talk about the second question first. Although nowadays our knives, in most instances are cleaned after each use and can be considered clean, and will not need ne’itza before cutting bread, however it is still not l’chatchila to cut bread or zucchini that will be used for milk with a meaty knife, and only if he doesn’t have another knife.
Regarding the first question, if the knife was indeed clean, (even if it would have been a ben yomo, the fact that it cut hot milky quiche and its absorbed taste is not relevant here) and the zucchini cut was cold and not sharp no taste is going to come out. The only issue here is that such a knife should not be used for items used for meat; however the poskim say that this is all l’chatchila, that we shouldn’t use such a knife, however in our case, that the knife was already used
Y:D 89-4, Taz -6, Aruch Hashulchan 16, Chochmas Odom 40- 14, Shach 22, Pri Megadim Mizbitzos Zahav ibid 6, Daas Torah 96-4, Ma’adanei Hashulchan in Matamei Hashulchan 89- 17, and Ma’adanei Hashulchan ibid 57.