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Kosher Issues in L-Cysteine

Chagiga I:8

Rabbi Zushe Yosef Blech

© 2003 Rabbi Blech; Reprinted with permission from MK News and Views Volume IV, Issue 6 - Lag B'Omer Edition - Iyar, 5763 / May 2003.

The Mishnah at the end of the first chapter of Maseches Chagigah (I:8) notes that the Halachos of Shabbos, Chagigos (sacrifices brought on the Festivals) and Me'ilos (prohibitions relating to benefiting from holy items) are like "mountains suspended by a hair" because their myriad of complicated Halachos is based upon but few scriptural references. In the realm of food production, the determination of the Kosher status of many ingredients is often based upon the analysis of specific intricate Halachic concepts. However, the determination of the Kosher status of one obscure chemical - known as l-cysteine - is virtually unique in the encyclopedic breadth of Halachic erudition that it commands. Seldom in the field of Kashrus has one ingredient been the subject of so many disparate and interesting Sheilos.

L-cysteine is an amino acid, one of a category of organic acids that contain a nitrogen-bearing amino group. Of the over 100 distinct amino acids, only about twenty serve as the precursors of all proteins - the fundamental building blocks of life. Additionally, several individual amino acids have specific uses in the food industry. For example, two amino acids - l-phenylalanine and l-aspartic acid - can be combined and modified to produce aspartame, which is used as a sugar replacer. Glutamic acid, often used in its salt form monosodium glutamate (MSG), serves as a flavor enhancer.

L-cysteine has two major food applications. The first is as a dough conditioner that, in some ways, is a modern manifestation of the brachos (blessings) conferred upon Bnei Yisroel. The Torah assures us that we will be so blessed with grain that we will only eat aged grain - V'Achaltem Yoshon Noshon - "and you shall eat very aged (grain)". Chazal tell us (Baba Basra 91b) that this verse teaches us that aged foods have superior qualities, and, indeed, the baking properties of flour improve when it is stored for some time after grinding. The characteristic elasticity of bread dough is attributable to two sulfur-rich proteins (gliadin and glutenin) present in wheat. As the dough is kneaded, the bonds between these two proteins are developed forming gluten and creating a dough structure that allows the carbon dioxide produced by the yeast to be entrapped and the bread to rise. The strength of gluten must be controlled so that it is not too strong, and aging flour served this purpose by allowing for the oxidation of the protein by exposing it to the oxygen in the air. Today, however, flour is routinely used within one week after grinding, so it doesn't get enough time to ripen and benefit from the bracha of Yoshon Noshon. To address this issue, food chemists have found chemical forms of bracha which have the ability to effect "instant" aging. l-cysteine contains certain sulfur-based components that react with the wheat proteins to weaken their sulfur bonds, thus allowing for more efficient dough formation. The other common food use of l-cysteine is as a component in savory (meaty) flavors produced through a Maillard reaction, the reaction of certain sugars with amino acids. When using l-cysteine in such reactions, food scientists have been able to produce a variety of chicken, beef, and other meat flavors that may be Kosher and Pareve.

Most amino acids used in the food industry are fermentation products, where specific microorganisms produce the desired amino acid as part of their metabolic processes. In such cases the Kosher status of the amino acid is generally a function of the material that is fermented. For example, if Chometz wheat glucose is fermented into glutamic acid, MSG that is made from it would be considered Chometz. l-cysteine, however, has historically been extracted from feathers and hair - human hair, to be specific. It is the Halachic status of these raw materials - and the Kashrus concerns peculiar to them - that have been the basis of questions that span the breadth of the Shulchan Aruch.

Human hair is rich in two basic amino acid compounds, l-cystine and l-tyrosine, with l-cystine comprising up to 14% of the hair. When hair is dissolved (hydrolyzed) in hydrochloric acid, these compounds can be separated and recovered. L-cystine is actually comprised of two l-cysteine amino acids that are joined together, and when this bond is broken using a hydrolysis reaction, l-cysteine is released. Human hair, while not particularly appetizing, is Kosher, but the source of the hair may pose a problem. Virtually all of the hair used in the production of l-cysteine comes from Asian countries, where both an ample supply and an inexpensive means of collecting it exist. When l-cysteine first came on the market, some concern was expressed that the hair was actually harvested from cadavers. The Shulchan Aruch (Y.D. 349:1) rules that one may not derive any benefit from a dead human body. Although some Rishonim (Rambam and Smag) permit the use of hair, the Shulchan Aruch (Simon 2) follows the position of the Ramban and the Rashba and extends the prohibition to this material as well. Fortunately, however, no one has ever been able to substantiate the use of hair from this source in the production of l-cysteine, and the consensus is to discount this concern.

Kashrus issues relating to human hair are not limited to l-cysteine, however. Halachic norms of modesty dictate that married Jewish women must cover their hair in public, and this is commonly accomplished by wearing the proverbial sheitl (wig). Although Rav Moshe Sternbuch, in his Das V'Halacha, raises a number of questions regarding the appropriateness of using human hair for the sheitl, one of his concerns is applicable to l?cysteine as well. Indeed, the issue devolves unto the source of the term amino acid itself. In the 8th century, an Arabian alchemist named Musa Jabir Ibn Hayyan refers to strange salt-like crystals on the walls of the temple of the Egyptian deity Amon. He called this material sal ammoniac, or the "salt of Amon". We now know that the source of this material was the soot from the camel dung that was burned in the desert temple which, as opposed to wood, contains a substantial amount of biologically reactive nitrogen. Ammonia, and its related amine compounds (including amino acids), thus take their name from this pagan deity.

In our situation, concerns of idol worship stem from a pagan ritual common in some countries involving the sacrifice of one's hair to the deity. It seems that women would grow a full head of hair and then shave it off, and offer it to the idol. Rav Sternbuch postulates that the priests attending these idols would subsequently remove the piles of proffered bouffant and surreptitiously sell them to wig makers. Since such items would be considered Takruvas Avodah Zarah (offerings to idols), it would be prohibited to derive any benefit from them (see Y.D. 139:1). Halachically, items offered to idols may be of greater concern than the idols themselves, since a non-Jew may void the status of an idol (bitul) but not the items that have been sacrificed to it (Ibid., 2). As such, were such a concern to exist with the hair used in the production of l-cysteine, its decomposition during processing would not mitigate the problem. Upon further analysis, however, it seems that l-cysteine should be immune to this concern. First, it turns out that the hair used in this process comes exclusively from local barber shops. A sophisticated collection system has been implemented in certain Asian countries, which is able to supply the needs of the l-cysteine industry without raiding the temples. Second, it has been argued that even if the hair were indeed donated to the idol, such an action would not be sufficient to cause the hair to be considered Takruvas Avodah Zarah. The Shulchan Aruch (Ibid., 3) stipulates a Halachic distinction between different types of materials offered to idols. Items that are similar to those offered (L'havdil) on the Mizbayach (altar) in the Bais Hamikdash (K'ein P'nim) become prohibited regardless of the method by which they are offered to an idol. Other items, however, must be offered in a manner similar to offerings in the Bais Hamikdash, such as through slaughtering or sprinkling (as blood was sprinkled on the Mizbayach) - Avodah K'ain P'nim. Since hair was never brought as an offering in the Bais Hamikdash, the mere act of placing it in front of the idol would not be sufficient to make it a prohibited item - such an act does not qualify as a "sprinkling" since the throwing does not break into small droplets or pieces (Zerika Ha'Mishtaberes). [It is interesting to note, however, that this argument would not resolve the concern were the hair actually cut in the service of the idol, since the act of cutting would be considered similar to the act of slaughtering. Further, in the opinion of the Rambam, any item that is actually placed directly in front of the idol (Lifnim min Ha'Kilklin) would be prohibited regardless of the manner in which it was offered.] Another point that may be noted is based upon the opinion of the Ma'Harsham (III:116), who postulates that it may be safely assumed that any item that is sold was not used in the service of an idol, since the pagan would not desecrate such items in such a manner.

Hair, however, is not the only commercial source of l-cysteine. Poultry feathers also contain substantial amounts of l-cystine, and are often processed in the same manner as hair for this purpose. While seemingly free of esoteric concerns of Avodah Zarah and posthumous benefit, it has been argued that feathers pose a more conventional Kashrus concern. When processing poultry, the best way to loosen feathers for easy removal is by dipping the slaughtered birds in boiling water. Such a process is not permitted for Kosher poultry, since one may not cook a bird until it is has been soaked and salted to remove the blood (Y.D. 68:10), and we must, therefore, often put up with more feathers on our Kosher birds than we would prefer. Non-Kosher poultry plants, however, have no such restrictions, and routinely scald their non-Kosher, bloody birds in boiling water before removing their feathers. While we may have no interest in non-Kosher poultry, it has been argued that we should be concerned with the feathers that have been cooked together with non-Kosher poultry and their blood. We may not eat feathers, but we do make l-cysteine from them, thus raising a potential Kashrus concern. Fortunately, however, given the manner in which the feathers are processed to produce l-cysteine, this matter poses no Halachic concern. Since the feathers are dissolved in hydrochloric acid and are rendered entirely inedible, any non-Kosher flavor or blood that may have been absorbed into them is considered Halachically insignificant. While many authorities do prohibit non-Kosher food that had been rendered inedible if it is subsequently returned to an edible state (e.g., gelatin made from non-Kosher meat sources), this would not pose a concern in this situation. In our case, the feathers were always Kosher - the only concern is the possible absorption of blood and non-Kosher flavor into them. Since the subsequent recovery of feathers into an edible item is not concerned with the blood or the flavor, these remain Halachically insignificant [see Igros Moshe (Y.D. II:23) in his discussion of blood that may be found on Kosher hides that are processed into gelatin.]

For those who find hair and feathers less than appetizing, food chemists have recently developed sources that may be more palatable. One company produces l-cysteine through the conversion of methyl acrylate into l-cysteine using an enzyme produced through fermentation. An even more recent advance involves recombinant technology, where the genetic coding of a particular microorganism has been altered to allow it to produce l-cysteine. As noted above, the Kosher status of fermentation products is based upon the Kosher status of the ingredients that are fermented, and both of these products are indeed Kosher certified.

As we have seen, the issues relating to l-cysteine traverse the gamut of Halachic literature. But it may also be interesting to note one more unique property of l-cysteine that was recognized in the time of the Talmud. The Gemorah (Shabbos 145b) relates that Rav Abbah had a special chicken recipe, which Rashi explains to be a chicken that he cooked and allowed to steep for several days in hot water until it dissolved, after which it was eaten for medicinal purposes. While Rashi does not indicate for what ailment chicken soup was prescribed, the Rambam prescribed just such a chicken soup to treat the asthma of Prince Al-Afdal in the court of Saladin. It seems that the l-cysteine naturally found in chicken feathers and skin is very similar to the mucus-thinning drug acetylcysteine, and chicken soup and its l-cysteine may indeed be just what the doctor ordered.

Chazal teach us that, at the time of Matan Torah, Hashem suspended Har Sinai above the Jewish people - Kafa Aleihem Har K'Gigis (Shabbos 88a). He then offered them a choice - either accept the Torah, or the mountain will be released and form their graves. When Bnei Yisroel accepted the Torah, they also accepted the requirement to delve into all of its intricacies, even the laws that the Mishnah refers to as "hanging by a hair". The Medrash (Tanchuma, Ki Savo) notes that the Pasuk refers to the Torah as being given HaYom HaZeh - "this day" - to teach us that we should look upon the Torah as if it were being given to us each day. Perhaps the zchus of learning the complex laws relating to l-cysteine and the hair from which it is derived will serve as one of "hairs" that keeps Har Sinai suspended above us each and every day.

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