Tevul Yom, Chapter One, Mishnah Five
1) Unshelled barley or spelt, root of crowfoot, asafoetida, silrhium–Rabbi Judah says: even black beansremain clean even [when coming into contact] with a father of uncleanness, and there is no need to say [if touched] by a tevul yom, the words of Rabbi Meir.
a) But the sages say: they are clean if touched by a tevul yom, but unclean [when touched] by other sources of impurity.
2) Shelled barley or spelt, or wheat whether shelled or unshelled, or black cumin, or sesame or pepperRabbi Judah says: also white beansbecome unclean even when touched by a tevul yom, and there is no need to say [when they have come into contact] with other sources of impurity.
Section one: This section lists pieces of grains or other foods that are not considered to be part of loaf of bread if found mixed up in there. If the loaf is terumah, and a tevul yom or a person with another type of impurity touches them but not the loaf, the loaf remains pure. In other words, these things won’t be eaten with the loaf so they are not part of the loaf.
I admit that I don’t know what some of these things are. But from what we can learn from this mishnah, they are not food commonly consumed.
The other sages are lenient when it comes to a tevul yom, for he is not truly impure. However, they rule stringently when it comes to people who are actually impure. If such a person touches these things, he defiles the entire loaf of terumah.
Section two: This list contrasts with that in section one. These foods will be eaten with the loaf. Therefore if even a tevul yom touches them, the rest of the loaf is defiled. We can see that these foods were considered more edibleshelled barley or spelt, wheat, spices. Interesting that Rabbi Judah thinks black beans are less edible than white beans. Bean racism?