Carmine- yes, the piske teshuvos brings down it’s muttar. There’s a pri megadim who says chazusa belo taama milsa hi in the part that discusses chazusa- it’s been years but i’ll try to find it tonight Kashrus agencies hold treif, based on Minchas Yitzchok, vol.3, 96, but chashuveh people say muttar.
This is from Rabbi kaganoff, good maareh mekomos:
The boldness of a color announces its existence. Can we say that a color is bateil when we clearly see evidence of its existence?
Several great halachic authorities discuss this question, reaching widely different conclusions. Some prohibit consumption of the resultant product precisely because one can notice its existence (Pri Megadim, Mishbetzos Zahav 100:1; Minchas Kohen, Sefer HaTaaroves 3:3, quoted by Darkei Teshuvah 102:30). They contend that bitul can only happen when the offending item leaves no trace. A colorant is by definition very noticeable and therefore not bateil. According to this approach, all of the juice drinks mentioned must be recalled since the non-kosher ingredient is very noticeable.
On the other hand, the Vilna Gaon argues that determining whether the food is kosher depends on whether one can taste the treif ingredient (Yoreh Deah 102:6). In our instance, although the color is noticeable, no one tastes the colorant, and therefore the finished product is permitted, assuming that the admixture was made in error. An earlier authority, the Minchas Yaakov (74:5), also espouses this position.
Some authorities concluded a position between these two positions, comparing our question to a Gemara that discusses whether someone who stole dye and cloth and now returns the dyed fabric fulfills his mitzvah of returning what he stole. The Gemara rules that this depends on whether the dye is considered to still exist after it has been used because its color is still noticeable (Bava Kamma 101a). Is the color on the cloth treated as if the dye itself still exists, or did the dye become bateil and no longer exists?
Last q from me:
A frum couple has a goyishe baysitter home all day. They sternly warn her not to use the kitchen or she will get fired, and then they both leave to work/kollel/school, leaving the baysitter at home by herself. Is the kitchen kosher (mirsas) or treif (no mirsas)?