Avodah Zarah, Chapter Five, Mishnah Nine
This mishnah contains a list of things that are prohibited and if even the smallest quantity of them is mixed up with a similar looking permitted item, the entire mixture is forbidden. The difference between this mishnah and the previous one is that here we are dealing with entire units, such as a cask of wine or an ox. If one of these which is forbidden such as a cask of wine that contains yen nesekh, becomes mixed in with a thousands casks containing kosher wine, they are all forbidden.
The following are prohibited and render prohibited by the smallest quantity:
1) [a cask of] yen nesekh;
2) an idolatrous object;
3) skins of animals which have holes over the heart;
4) an ox which has been sentenced to be stoned;
5) a heifer whose neck was broken;
6) birds brought as an offering by a leper;
7) the hair-offering of a nazirite;
8) the first born of a donkey;
9) meat cooked in milk;
10) the scapegoat;
11) and non-consecrated animals slaughtered in the Temple court.
Behold these are prohibited and render prohibited by the smallest quantity.
1) If one cask of yen nesekh is mixed up with even one thousand kosher casks, they are all forbidden.
2) If one statue used for idolatrous purposes is mixed up with even one thousand statues that were not used in idolatry, they are all forbidden.
3) In chapter two, mishnah two, we learned that idolaters would make circular holes and take out the animals heart and use it in worship. If a piece of one of these skins is mixed up with a large quantity of regular animal skins, they are all forbidden.
4) An ox that killed a man is to be sentenced to death (Ex. 21:28). If this ox becomes mixed up with other oxen, they are all forbidden. Note that in all of the cases of live animals in this mishnah, the same rule is true if the meat of the animal is mixed up with the meat of other animals.
5) This heifer is the one referred to in Deut. 21:4. It is used to expiate the blood guilty for a murder where the murderer has not been caught. If this heifer, after it has been designated to be part of the ritual and is on its way down to the wadi where its neck will be broken, should become mixed up with other heifers, they are all prohibited.
6) When a leper becomes cleansed of his disease, he must bring two birds as a sacrifice (Lev. 14:4). If they are mixed up with other birds, they are all forbidden.
7) When a nazirite ends his term of naziriteship, he must shave (Num. 6:18). Should his hair, once it is shaved off, become mixed up with other hair, it is all forbidden. In other words, no nazirite hair wigs!
8) The first born of a donkey is usually redeemed by giving a sheep to the priest in place of the donkey (Ex. 13:13). If this newborn donkey should become mixed up with other donkeys before it is redeemed, they are all forbidden.
9) If a piece of meat, cooked in milk should become mixed up with other kosher pieces of meat, they are all forbidden.
10) The scapegoat is the goat sent to Azazel on Yom Kippur (Lev. 16:22). If it should become mixed up with other goats, they are all forbidden.
11) It is forbidden to slaughter non-sanctified animals in the Temple court. If the carcass of an animal slaughtered in this fashion should become mixed up with other carcasses, they are all forbidden.