Checking Quinoa: a Halachic Analysis


By Rabbi Yair Hoffman for

This past month, a Kashrus alert has been issued in regard to Quinoa by a number of Kashrus agencies, including the Star-K.  It seems that Quinoa sold in the Northeastern USA has been found to be infested due to issues in the distribution chain and storage. The Star K reports that the issue is more widespread than previously thought, and that affected batches were found in markets from NY to Maryland. Booklice and mites seem to be the most common insects being found in quinoa, according to the alert.

Our question is, does Halacha require that Quinoa be checked with the lightbox method as the alert recommends?  If someone is serving you Quinoa – are you required to avoid it – if you think it was not checked properly?

Of course, each person should ask his or her own Posek.  This article will discuss two things.  It will discuss the operative term that we all need to know – Miut HaMatzui. It will also discuss the different views among the Poskim about Mi’ut HaMatzui.

So here goes.


Miut HaMatzui is a term that is applied to Quinoa, Shaatnez, missing husbands, and chickens.  The parameters of this term determine many, many, things other than Quinoa.  May we buy and immediately wear Uggs?  May we eat that Quinoa or brown rice presentation at the wedding we are now attending?  Is the chicken that Uncle Feivel buys kosher enough for his nephew in Monroe on account of the somewhat prevalent Tzumas HaGiddin problem – ripped veins in the back of the chicken’s knees?

The translation of this term means “a prevalent minority.”  The Gemorah in Chullin (11a) tells us that by Torah law we may (and do) follow the majority.  There are, however, some exceptions.


One such exception (according to most Poskim and the Shulchan Aruch) is is when there is a prevalent enough minority.  Some examples are:

A husband falls of a ship in deep never-ending waters.  No body is found.  Can she remarry based upon an assumption that no one survives such a fall?  No, states Tosfos (Niddah 44b “Dakim” and Yevamos 36a “ha”) – because a prevalent minority do, in fact, survive.

A man was on his deathbed.  This was witnessed, but they did not actually see him die.  May his wife remarry?  No, says the very same Tosfos.  There is a prevalent minority that get up from what seemed to have been their deathbed.


The Ramah in Yore Deah 84:8 writes that in regard to checking vegetables for bug infestation it is insufficient just to check one out of a pack – when there is a Miut HaMatzui – a prevalent enough minority.   The Ramah’s ruling is based upon a responsum of Rabbi Shlomo ben Aderet (1235-1310) also known as the Rashba.  He writes (Vol. I #274) that even if the vegetable is not muchzak b’tolaim,  known to be infested – if there is a significant or prevalent minority – it must still be checked.


Another question is whether or not the obligation to be concerned for a prevalent minority is a Torah law or a rabbinic law.  This is a debate in the Poskim and is discussed in the Pri Magadim 384:28.  It seems from the Shach (YD 39:8 and the Pri Magadim in Sifsei Daas 39:3) that the halacha is that it is rabbinic in origin.  The Pri To’ar seems to learn that it is a biblical requirement.


The question is, however, what exactly is to be considered prevalent?  What percentage must we be concerned for in order to necessitate an examination for something forbidden?  It seems that there are at least seven different approaches in the Poskim as to how to calculate “prevalence” – if it can even be calculated at all.

  1. Rav Yitzchok ben Sheshet Perfet (1326-1408), otherwise known as the Rivash, writes in a responsum (#191) that it is close to fifty percent. There are two possible understandings of this Rivash:
  • It could be that he means that up until 49% it is still considered a non-prevalent minority. This is the classical understanding of the Rivash, but it is problematic – in that this is a plain ordinary minority.  What benefit is there to a non-prevalent minority over a regular ordinary minority?
  • The second possible reading of the Rivash is that he means 26%. How so?  Well 25%, is considered a quarter not a half.  26% would be considered closer to half.  This is how Rav Scheinberg zt”l reads this Rivash (see HaRav v’Rosh Yeshiva by R. Elchanan Peretz p. 118).  It is also explained in this manner by the Sichas Chulin as cited in Toras HaOf page 165).


  1. Rabbi Yaakov Minkowski (1780-1844), a student of Rav Chaim Volozhin, writes in his Mishkenos Yaakov (#17) that the parameters of “prevalent” is ten percent or more. The Mishkenos Yaakov brings a proof to his position from the Mishna in Gittin 31a that one should check wine three times each year since it is liable to turn to vinegar.  Without checking, one may not take off the gifts of Trumos and Maasros from the wines, and one is not permitted to rely on an assumption that the wines have not spoiled.  Elsewhere in the Talmud (Bava Basra 93b), the Mishkenos Yaakov points out, the percentages of spoiled wine in regard to sales is listed as generally being ten percent.  [Those that disagree with the Mishkenos Yaakov state that “bad wine” is different than vinegar.]


  1. The Beis Ephraim (YD #6) argues with the Mishkenos Yaakov and writes that one is only obligated to check for a prevalent minority when it is certain that it the minority is extant there somewhere. If there is a doubt about it – then there is no obligation.


  1. Rav Vosner zt”l (Shevet Halevi 4:81 and 8:180) distinguishes between two different types of minorities. He writes that when the minority is always accompanying the majority – then the concern for it is even when it is less than ten percent.  However, whenever the minority appears as mere chance – than one is not to be concerned for it.


  1. Rav Chaim Pinchas Scheinberg zt”l and lbc”l Rav Pesach Eliyahu Falk (cited in Madrich l’Bdikas Tola’im p. 10) are both of the opinion that it is not a hard and fast percentage but rather dependent upon whether a person is surprised or perplexed that it exists. According to this understanding, even if it is a low percentage, a person may not be shocked that it is infested.


  1. Rav Elyashiv zt”l is quoted by Rav Moshe Vaya as holding that seven percent or above is considered a prevalent minority and that one should be stringent at 5%. This is also cited as the view of Rav Chaim Kanievsky shlita (Hilchos Orlah in Sefer Levushei Yoseph).

Rav Shlomo Zalman Auerbach zt”l does suggest to use the figure of the Mishkenos Yaakov in Minchas Shlomo (Vol. II #61:1).  It is unclear to this author whether this is just a recommendation or a psak halacha.  Rav Meir Bransdorfer zt”l (1934-2009), author of the Knei Bosem, also rules (Vol. I #49) like the Mishkenos Yaakov.  Rav Yitzchok Yoseph, on the other hand rules (Issur v’Heter Vol. II Siman 84 p. 212) like the Rivash.  It seems also that he holds of the 49% reading of the Rivash and not the 26% reading.


There is another very important point that needs clarification.  For argument’s sake, let’s assume we take the Mishkenos Yaakov’s figure of ten percent – but ten percent of what?  For big ticket items such as people and chickens, the ten percent figure makes sense.  But what if we are discussing Quinoa – is it ten percent of each seed?  Is it ten percent of each bag?  Is it ten percent of each recommended serving?  What are the parameters here of what we are examining?

In Bdikas HaMazon K’Halacha (4:73), the author, Rav Moshe Vaya, cites a ruling from Rav Elyashiv zt”l that it is the general unit that is purchased, and when one is eating – it is the general portion that is being consumed.


Okay, so now that we know the different opinions about Miut HaMatzui – how prevalent is it?  Rabbi Dovid Goldstein of Boro Park is one of the leading bug infestation experts in the country.  Rav Moshe Vaya trusts him implicitly.  He says that the infestation levels of what he has examined is between 20% to 30%.  So let’s go through each of the aforementioned opinions.

  • According to the first reading of the Rivash – one does not have to check Quinoa. According to all opinions it is less than 49%.  According to the second reading – it may require checking.  The second reading holds that a Mi’ut HaMatzui is 26%. According to the Mishkenos Yaakov it should be checked since it is more than 10%.
  • According to the Beis Ephraim one does not need to check in this case. According to Rav Vosner one does not need to check in this case either.
  • According to Rav Scheinberg and Rav Falk it should be checked because it is now common knowledge and not surprising at all that Quinoa can be infested. Goyim posted videos about it four years ago.
  • According to Rav Elyashiv zt”l and ylct Rav Chaim Kanievsky shlita – it should be checked because it is more than 5%.
  • According to Rav Yitzchok Yoseph – it need not be checked because he relies on the first reading of the Rivash.

This author’s own conclusion is slightly nuanced.  Generally speaking, it should not be eaten unless it was checked – but each person should check with his or her own Posek.

The author can be reached at


  1. When a agency whose mashgichim supervise a food product tells us that the product needs inspection by the consumer, that recommendation should carry extra weight!

  2. Why?
    Don’t they have more negios than anyone else?
    After all, they need to protect their reputation.
    This way, no one can blame them.
    (I’m not saying there isn’t a problem with quinoa.
    Just saying that there is no reason the hashgacha’s opinion carries extra weight.
    If anything, the opposite.)


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