2,450. Significant Things

Maachalos Assuros 16:2

Pursuant to the previous halacha, if yeast from trumah wheat falls into a dough from regular wheat and it’s enough to leaven the dough, the whole dough is considered mixed with trumah. Similarly, if trumah spices fall into a pot of regular food that has the same spice in it, if the trumah is enough to season the dish, the whole thing is considered mixed with trumah. This is so even if the volume of yeast or spices is one-thousandth that of the permitted food. Similarly, if yeast from mixed species of a vineyard fall into dough or if spices of orlah fall into a pot, one is not permitted to benefit from the whole mixture.

Maachalos Assuros 16:3

Even the smallest volume of something significant can render a mixture of the same kind prohibited. These seven things are considered significant: nuts from Perech, pomegranates from B’den, sealed barrels, beet stalks, heads of cabbage, Greek squash and the loaves of a homeowner.