Piggul and nossar do not combine with each other, because they are two [distinct] names. A sheretz and neveilah, as well as neveilah and flesh of a [human] corpse, do not combine with each other to transmit tumah even like the more-lenient [aspect] of the two. Food that contracted tumah from an av hatumah and [food] that contracted tumah from a vlad hatumah combine with each other to transmit tumah like the more-lenient [aspect] of the two.

All foods combine with one another: to disqualify one’s body with half a peras; for the food of two meals for an eruv [techumim]; for the egg’s volume to transmit the tumah of foods; for the dried fig’s volume for carrying out [of a domain] on the Sabbath; for the date’s volume on Yom Kippur.  All beverages combine with one another: to disqualify one’s body with a revi’is and for the “fill of a cheek” on Yom Kippur.