Items That Cannot Be Nullified
This is the approved revision of this page, as well as being the most recent.
Complete Natural Items (Biryah)
- If a whole item from a living being is mixed into a mixture it isn’t nullified even one in a thousand, whether or not it is mixed with like or unlike ingredients. For example, an ant, non-kosher bird, sciatic nerve, and a limb that was detached from a kosher animal are considered whole items and not nullified. 
- A item from a living being is only considered significant and not nullified if it meets 4 conditions:
- If there is a halachic doubt if an item is a biryah, it can be nullified, however, if there is a doubt if an item is forbidden but certainly is considered a biryah the item isn't nullified.
- If a biryah fell into a mixture and was removed, the taste it imparted to the mixture can be nullified in 60. If the biryah is unrecognizable and can't be removed, the entire mixture is forbidden.
- If a bug or another biryah fell into a soup and was lost, the entire soup is forbidden.
- If a bug fell into a soup and were crushed up, as long as there was a majority of the soup in comparison to the bugs, the soup is permitted. Yet, as long as it is possible check the soup and strain it one must.
- If 3 bugs are found in cooked vegetables they are forbidden because there is a established concern of bugs in these vegetables and once they are cooked they can't be checked well. 
- An egg with a blood spot potentially is considered a biryah. 
- A limb of a non-kosher animal or insect, an animal that died without proper shechita, and an animal who had a Teriefah defect are considered biryah.
- A limb of a kosher animal that was detached when it was alive is considered a biryah and isn't nullified. 
- The forbidden fats of an animal aren't considered a biryah and can be nullified. 
Important Foods used to Honor Guests
- An important piece of forbidden food, whether it is forbidden in benefit or not, that can be used to honor an important guest isn't nullified even one in a thousand.
- If there is a halachic doubt if an item is an important piece it can be nullified, however, if there is a doubt if an item is forbidden but certainly is considered an important piece the item isn't nullified.
- If a piece of food that's important falls into a mixture and is removed, the taste it imparted into the mixture is nullified in 60.
- If a food isn't currently ready to be served to guests but potentially could be made into a piece that is significant for guests, according to some rishonim that is considered significant and isn't nullified, while according to others it is nullified if it isn't currently ready to be served. Ashkenazim hold that if it is almost ready to be served it is already important and can't be nullified, however, if there is a major activity to still do, such as removing the feathers from a chicken, it can be nullified. Sephardim hold that if the piece is too big or too small or is unfeathered it can be nullified, however, if it is just raw, where there's no minhag one should be strict and assume that it can't be nullified.
- It is only considered an important piece that can't be nullified if it is forbidden in it of itself such as nevelah or a combination of meat and milk but not if it just absorbed the taste of a forbidden food.
- If an important piece is cut or crushed up so that it lost its original form it no longer retains its significant status and can be nullified. That is only if it was cut or crushed unintentionally.
- If an important piece fell into a mixture and one piece was cut, that piece is permitted but the rest of the mixture is forbidden. 
Items which will become Permitted
- An item which is either inevitably going to become permitted after some time or it is possible to for you fix it, isn't nullified.
- If a food will get completely ruined before you can wait for it to become permitted, it isn't considered an item which will become permitted and can be nullified. However, if it'll just cool down, it can't be nullified.
- An item which will become permitted isn't nullified even if it isn't whole.
- There is a major dispute if the absorbed taste from an item which will become permitted can be nullified. 
- An egg born on Yom Tov is something which will become permitted after time. Nonetheless, it is permitted to buy (without specifying the price or amount) an egg on the first night of Yom Tov (which doesn't fall out after a Shabbat) since majority of eggs are born by day.
- If there's a doubt if something is muktzeh on Yom Tov sheni it is permitted. 
- Something that is forbidden to a person because of a vow is considered an item that will become permitted since one could or should nullify one's vow by annulment.
- An egg born on Shabbat or Yom Tov is considered an item that will become permitted since it is permitted after Shabbat or Yom Tov. The same is true of all muktzeh.
- Some say that Chametz on Erev Pesach which is going to be permitted after Pesach, but will become forbidden next Pesach, isn't considered an item that will become permitted. Some argue and Sephardim are strict.Chametz on Pesach isn't nullified. 
- Chadash is an example of something that will become permitted and as such there's no nullification.
- Chullin 100a says that the sciatic nerve isn’t nullified when in a mixture of other sinews because it a complete item. From here the rishonim extrapolate that all complete items are considered significant and not nullified. This is codified in the Rambam (Maachalot Asurot 16:6), Tur, and Shulchan Aruch YD 100:1.
- Rash (Mishna Trumot 10:8) writes that a complete living item is nullified with an amount 960 times greater than its volume of permitted ingredients. The Rashba (Torat HaBayit 14b) agrees. However, the Rosh (Chullin 7:37) and Ran (Chullin 32b) disagree and say that the mishna Chullin 96b compares the piece that is used to honor guest and a complete item from a living being and a piece that is used to honor guest isn’t nullified even one in a thousand. Shulchan Aruch YD 100:1 and Gra 100:5 rule that a complete item from a living being isn’t nullified even one in a thousand.
- Torat Chatat 40:6 and Taz 101:12 in response to the Isur Veheter HaAruch 25:17
- Shulchan Aruch YD 100:1
- Gemara Macot 17a sites the opinion of the Rabbis who disagree with Rabbi Shimon that only a complete item from a living being is significant. The Ritva (Chullin 100a) and Taz 100:1 point out that the significance of a living being found in the area of Malkot, as is the subject of the discussion between Rabbi Shimon and the Rabbis, is applied on a rabbinic level to nullification. The idea that only a living item is significant for the halacha of biryah is mentioned by the Ran (chullin 36a s.v. garsinan). Therefore, Shulchan Aruch YD 100:1 writes that a kernel of wheat isn't a biryah.
- Ran (chullin 36a s.v. garsinan), Shulchan Aruch 100:1
- The Kaf HaChaim 100:19 qualifies that if a little bit of it is lost int he cooking process as is normal it retains the status of biryah.
- Ran (chullin 36a s.v. garsinan), Shulchan Aruch 100:1
- Rosh (Chullin 7:33), Shulchan Aruch 100:1. All four of the above conditions are summarized by the Pri Megadim (S”D 100:3).
- Isur Veheter HaAruch 25:7, Taz 100:1
- Mishna Chullin 96b, Shulchan Aruch YD 100:2
- Rashba (responsa 1:101), Shulchan Aruch YD 100:3
- Rashba (Torat Habayit 16b), Shulchan Aruch YD 104:3
- The Bach 100:3 writes that we should be strict to forbid the vegetables even if 2 bugs are found, however, the Taz 100:6 defends the Rashba who says it is only forbidden if 3 bugs are found. The Aruch HaShulchan 100:12 and Kaf HaChaim 100:34 agree with the Taz.
- Rashba (responsa 1:113), Shulchan Aruch YD 100:4.
- The Rashba (responsa 1:113) draws upon sources from the gemara to say that clearly there is an obligation to check vegetables for bugs.
- For more sources about checking for bugs, see Aruch Hashulchan 103:11 and Igrot Moshe YD 4:2.
- The Bet Yosef 110:1 is unsure in understanding the Rambam where just an egg that has an unborn chick is considered a biryah or even an egg with a blood spot is considered a biryah. In the Bedek Habayit he concludes leniently that the egg with a blood spot isn't considered a biryah. The Shach 101:2 argues that it certainly isn't a biryah since it was never a living being. This seems to be the opinion of the Rashba (Torat Habayit Hakatzar 8a). See further in the Bet Yosef 86 and Rambam (Maachalot Asurot 15:19) who implies it is a biryah.
- Pri Chadash 100:7, Chavot Daat 100:2, Kaf HaChaim 100:6
- Shulchan Aruch YD 100:1, Shach 100:4, Kaf HaChaim 100:12
- Rosh (Chullin 7:33), Isur Veheter 25:2, Shulchan Aruch YD 100:1
- The Shach 100:5 explains that since cut up fat is also called fat it isn't considered a biryah based on the fourth condition of biryah above. The Ran (Chullin 36a s.v. garsinan) explains that the forbidden fats aren't considered a biryah since they are dispersed and not one unit. Kaf Hachaim 100:16 quotes both explanations.
- Even though the Rif (Avoda Zara 35b) seems to hold that only items that are forbidden in benefit have this particular halacha that an important piece can't be nullified, the majority of the poskim have disagreed with the Rif as the Bet Yosef 101:1 writes. The Tosfot (Avoda Zara 74a s.v. lemeutei) and Rambam (Maachalot Asurot 16:5) disagree with the Rif
- Kaf HaChaim 101:1 and Aruch Hashulchan 101:1 write that the food needs to be important enough that it would be used to honor an important guest.
- Shulchan Aruch YD 101:1
- Isur Veheter HaAruch 25:7, Rama 101:1, Taz 100:1
- Kaf HaChaim 101:3
- Rosh (Chullin 7:36)
- Rashba (Torat Habayit 13b)
- Shulchan Aruch YD 101:3 holds as long as the piece isn't the right size, unfeathered, and cooked it can be nullified. Rama YD 101:3, however, that as long the chicken was feathered it can't be nullified. Kaf HaChaim 101:27 advises being strict about an uncooked piece but notes that the minhag of Yerushalayim was to be lenient and they have what to rely upon.
- Shulchan Aruch YD 101:2
- Shulchan Aruch YD 101:6
- Rosh (Chullin 7:35), Shulchan Aruch 101:7
- Rashba (Torat Habayit 12b), Tur and Shulchan Aruch 102:2. Shach 102:7 writes that everyone agrees to this definition and proves it from the Gemara Beitzah 3b. Shach 102:8 cites the Maharshal who argues that someone which can be fixed but won't become permitted on its own isn't considered an item which will become permitted. The Shach proceeds to reject on the Maharshal because of the case of neder.
- Kaf HaChaim 101:19
- Gemara Beitzah 4b, Rashba (Beitzah 4a s.v. Ha Deamrinan), Shulchan Aruch 102:4
- Kaf HaChaim 102:21
- Shulchan Aruch YD 102:1
- The Rama 102:4 holds that the taste of an item that will become permitted can be nullified, even if the actual forbidden item was dissolved into the permitted food. The Rama is based on the Isur Veheter 25:17 and 25:19, yet see Shach 102:9 who disputes this interpretation of the Isur Veheter. Hagahot Ashri (Avoda Zara 5:29) is explicitly of this opinion. The Taz 102:9 argues that only taste from a forbidden item that will become permitted can be nullified, but not if the actual item dissolved into the permitted food. The Shach 102:9 holds that all taste from an item that will become permitted cannot be nullified. Kaf HaChaim 102:24 cites the Chaye Adam 53:21 who is strict unless there is a great need. Regarding the actual item being dissolved, the Shach 102:10 argues that it certainly can't be nullified and Kaf Hachaim 102:25 writes that all of the achronim agree with the Shach.
- Shulchan Aruch OC 323:4
- Rosh Beitzah 1:9 writes that since majority of eggs are from a hen and chicken and could only be born by day one can buy an egg on the night of Yom Tov or the second day of Yom Tov sheni. This is similar to Tosfot Beitzah 7b s.v ki and Ran (on Rif Beitzah 4a s.v. vedavka). The Maharshal (Yam Shel Shlomo Beitzah 1:20) explains that really you need two independent majorities to be lenient; first that rov eggs are from a hen and chicken and could only be born by day and second, that rov eggs that were from the heat of the ground are still born by day. He draws support from the Tur 513 and disagrees with the Ran's explanation that even a single majority is sufficient. Bet Yosef 513:6 writes the the Ran's generalization that one majority is enough to permit a derabbanan even if it is a dvar sheyesh lo matirin is disputed by many rishonim.
- The Ran (Beitzah 13a s.v. gemara ein halacha) writes that it is permitted to use something that there's a doubt if it is muktzeh on Yom Tov sheni since it is a safek safeka. Shulchan Aruch 497:4 codifies the Ran. Shach YD 110:56 discusses if the Rama who agree and he concludes that he would.
- Gemara Nedarim 59a, Isur Veheter HaAruch 25:4, Shulchan Aruch YD 216:9, Rama 102:4. The Kaf HaChaim 101:29 discusses whether this is true only for a neder where there is a mitzvah to annul it or even for a specific vow and concludes that for a great need one can be lenient on a shevuah.
- Gemara Beitzah 3b, Isur VeHeter HaAruch 25:4, Tur and Shulchan Aruch YD 102:1
- Isur VeHeter HaAruch 25:4
- Kaf Hachaim 102:32 cites the Erech Hashulchan who is strict because of the opinion of the Rambam.
- Shulchan Aruch OC 447
- Gemara Nedarim 58a, Rosh (responsa 20:1), Shach 110:56. See, however, the Chidushei Anshei Shem (Beitzah no. 1) who explains that the Mordechai holds that Chadash isn't a dvar sheyesh lo matirin.