Products from the chemical industry improve the quality of human life throughout the world. Consumers have come to assume that starting materials, methods of production, and end products will all meet the highest of standards. But people in certain faith communities expect even more: strict conformance to religious regulations throughout the production process. Here we examine this unusual interface between chemistry and religion, drawing upon examples from Islamic and Judaic law, to discover the preparation processes involved in the making of permitted or “clean” halal and kosher products.
2. Industrial Practice with Respect to Kosher and Halal Production 
From an industrial point of view, the goal of certification as halal or kosher for a line of products represents the opening of a new market, and for religious authorities it means providing believers with products in accord with their faith. It is important to emphasize that both parties have an interest in successful certification. Since mere words, or the simple inscription halal or kosher, cannot in themselves confer any protection, such products must ultimately be granted an official seal, one that carries legal recognition. Thus, every certifying agency possesses its own unique seal, and only this seal guarantees that a product has been prepared under the oversight of designated religious authorities, and can thus be consumed without hesitation by the faithful.
As with every seal of approval, there is bound to be a certain amount of variability with respect to reputation and quality of the certifying body. Jews know the legitimate kosher seals very well, but in the case of Muslims the situation to date is still rather unclear, since the mere legend “halal”’ printed on a package is not necessarily very reliable given the absence of international quality standards (Fig. 2). An interested industrial firm from the chemical sector should from the outset associate itself only with reputable religious partners, who themselves enjoy international recognition.
Figure 2. Kosher and halal seals.
Consider a chemical corporation, one involved, for example, in the further processing of tropical vegetable oils. It would seem at first glance to be child’s play to prepare products that are halal or kosher: The crude vegetable oils are already, so to speak, kosher and halal by their very nature, so it should be necessary only to make sure that at every step in the processing operation no extraneous “impure” materials are introduced. In practice, however, certification proves to be considerably more complicated.
To begin with, the entire processing facility must be made “clean” from a religious perspective. This alone can turn out to be a very elaborate and costly operation, and in some cases one that is in fact technically impossible (see Halal and Kosher Food Production: Interview with Prignitzer Marketing Director and Chief Executive). Sometimes it requires construction of a separate plant for the exclusive purpose of producing kosher or halal goods.
An important goal of certification is exclusion from the outset of any potential contamination by “impure” materials. For example, form oil used as a release agent, or lubricants and emulsifiers, might contain components from an animal source. Or processing aids such as glycerin, or added flavoring or fragrance substances, could be of animal origin. Only after unambiguous establishment of the “clean” nature of all compounds entering into manufacturing or preparation steps can an end product be certified as truly kosher or halal. Due to often tricky chemical details, rabbis or halal auditors not themselves trained in the natural sciences may seek help from their own chemists, chemical engineers, or even food chemists as part of the certification process.
2.1 Absence of th Official Kosher Seal
The German food sector exports a great many products with kosher and/or halal certification, ensuring as well that the associated packaging bears an appropriate seal (Fig. 2). In the United States, ca. 30 % of all products on the supermarket shelves carry a kosher seal. Within Germany one often looks in vain for such a seal on the very same products! Perhaps companies simply want to save paying the certification charge, but it may also be that they are afraid the presence of such a religious symbol might somehow have a negative impact on sales. In any event, this means that German orthodox rabbis must publish lists of foods that are inherently kosher, despite their perhaps not being so labeled .
The sample descriptions of the industrial practice with respect to kosher and halal production that follow are based on information from Z. Y. Blech  and A. Zaidan .
Gelatin is a protein obtained by cooking up connective tissue; in other words it is derived from bones, tendons, and skin [18, 19]. Gelatin has unique material properties: dissolved in warm water, the resulting solution gels at low temperature and becomes firm. It is often utilized in the preparation of a host of foods—from glazes, to fruit yogurt, to gummi bears.
Both of the religions in question have had their hands full with gelatin, and entire books are based on the resulting back and forth argumentation. Gelatin derived from fish, or beef slaughtered in a kosher or halal way, is of course permitted. But beef gelatin is relatively tough, and less appropriate for many applications relative to the more pliant pork gelatin. One would presume that pork gelatin, derived as it is from an “impure” species, could never be certified as kosher or halal, but the true situation is in fact more complicated than that.
Barely 50 years ago, a particular American confectioner wished to prepare kosher marshmallows. Such a sweet was already known in ancient Egypt, derived from mallow (Athaneae officinalis) growing in the local marshes, mixed with honey and nuts. Today, however, the main ingredient in marshmallows is gelatin, and over 80 million pounds are consumed annually in the United States alone.
As a precautionary measure, Jewish authorities in both America and Israel were contacted and asked for advice. The first response came as no surprise: pork gelatin is not kosher! A suggestion was made, however, of one manufacturing approach that might produce a kosher pork gelatin.
In the Torah, only the consumption of pork meat is forbidden, but cleaned, sufficiently dried (i.e., “bone dry”) material, free of actual pork, could surely serve as a basis for a kosher gelatin. Two American firms began production—under strict supervision—of such a product, but it proved impossible to conduct the process in an economically viable way. A few American rabbis agreed to sanction gelatin production under a somewhat less strict regimen, but the most important Jewish authorities stuck by the decree that pork gelatin is not kosher.
Today, kosher sweets of this kind are prepared with either fish gelatin or a plant-based thickening agent made from seaweed. The adaptation makes possible, for example, the manufacture of vegetarian gummi bears, and it allows the Haribo company to export a kosher version of “Gold Bears” (Goldbären).
Gelatin is utilized not only in foodstuffs, but also in the pharmaceutical field, especially for preparing easily swallowed medication capsules. Such capsule material is not available in an authorized kosher or halal form, but individual believers are counseled to take all medications prescribed for them without remorse, since “necessity knows no law” (Fig. 3).
Figure 3. Halal status of medications. Translation: Muslim patients may also take Pangrol®.
Chapter 2 Verse 173 of the Koran says:
He has only forbidden to you dead animals, blood, the flesh of swine, and that which has been dedicated to other than Allah. But whoever is forced [by necessity], neither desiring [it] nor transgressing [its limit], there is no sin upon him. Indeed, Allah is Forgiving and Merciful.
What is crucial here is that the believer is not consuming these capsules as a food, and not out of enjoyment, but rather for the maintenance or restoration of health. Muslims are able to fall back directly on the Koran :
O mankind, eat from whatever is on earth [that is] lawful and good and do not follow the footsteps of Satan. Indeed, he is to you a clear enemy.
And to those who are Jews We prohibited every animal of uncloven hoof; and of the cattle and the sheep We prohibited to them their fat, except what adheres to their backs or the entrails or what is joined with bone. [By] that We repaid them for their injustice. And indeed, We are truthful.
Preserving agents based ultimately on petroleum products always qualify as kosher or halal. Examples include benzoic, sorbic, acetic, and propionic acids, as well as their sodium and potassium salts. On the other hand, manufacturing processes for lactic, tartaric, and citric acids are generally based on natural starting materials, and are subjected to careful scrutiny with respect to the extent to which animal sources may somehow have been utilized.
Another problematic case involves the production of wine vinegar, which may entail bacterial fermentation either of wine itself or of a diluted grain alcohol. Kosher wine vinegar may only be prepared from a kosher wine. In the fermentation of what is essentially a mixture of pure ethanol and water, nutrients must be added to permit growth of the acetic acid bacteria. These additives must in turn themselves be kosher (or halal, as the case may be), which is to say they cannot contain any “unclean” animal material.
Incidentally, since the alcohol solution is prepared from grain, generally wheat, the corresponding vinegar could not be consumed during Passover week. Consumption of all alcohol is forbidden for Muslims, but the acetic acid prepared from ethanol is regarded as a completely new product, one that will be halal so long as the residual alcohol content is minimal (under 0.5 %).
2.4 Food Colorings
Food colorings of synthetic or plant origin class inherently as halal and kosher. Regardless of source, such dyes, of course, must be recognized as legal for human consumption. Jews and Muslims never regard dietary laws of a religious origin as substitutes for a country’s food laws, but rather as—for them extremely important—supplements to the latter. Somewhat surprisingly, this status as “permitted” does not apply to the food pigment carmine, the bright-red aluminum salt of carminic acid (1), see Fig. 4 (C.I.—International Colour Index—75470, or European Commission E 120; also known as cochineal or Natural Red 4).
This natural dye is obtained from the scaled insect cochineal (Dactylopius coccus) found on cacti of the genus Opuntia, native to tropical and subtropical South America and Mexico and bred as well in the Canary Islands. The dye makes up as much as 15 % of the dry weight of dried females of this insect species. Since consumption of insects is forbidden in both the Jewish and Muslim religions, kosher and halal foods may not contain Natural Red 4. Interestingly, this means Jews are therefore not allowed to drink Campari, whose scarlet color is derived from cochineal insects.
The synthetic dye Cochineal Red S (2) (Ponceau 4R, C.I. 16255, C.I. Red 18, E 124, Brilliant Scarlet 4R), though currently listed as a banned carcinogen in the United States, produces the same color, and is inoffensive from a religious standpoint.
Figure 4. Kosher and halal status of coloring agents.
Margarine is an oil/water emulsion, where the oil phase contains hydrogenated vegetable fat, the dye carotene, emulsifiers, and oil-soluble flavoring agents, while the aqueous phase includes salt, water-soluble flavoring agents, thickening agents, and often preservatives. Since whey or milk proteins are sometimes present as well, kosher margarine is regarded by Jews as a dairy food, and may thus not be used in the frying of meat.
In this context, an interesting chemical detail relates to the hydrogenation of vegetable oils. Hydrogenation of double bonds causes the melting point of a fat to increase, giving what is logically known as a hydrogenated fat. This hydrogenation is conducted at elevated temperature and pressure in the presence of Raney nickel, a metallic catalyst prepared from an aluminum/nickel alloy by dissolving out the aluminum with the aid of a strong base. Due to its high reactivity, active Raney nickel must be stored under a layer of oil. In the certification of a kosher or halal margarine production process, the certifying agency pays strict attention to the question of whether the oil employed here is itself appropriately kosher or halal!
Sweeteners like saccharin (3) and cyclamate (4) (Fig. 5) are synthetic products based on petroleum, so they should qualify as kosher or halal. Only a few milligrams of a sweetener are required to achieve the sweetness of an ordinary sugar cube, so fillers like lactose and magnesium stearate are added to facilitate compression into convenient tablets. And this is where the problems begin, since stearic acid is often derived from fat coming sometimes from “unclean” animals, and lactose comes from whey, so any dish so sweetened would need to be regarded as “dairy” from a Jewish standpoint.
Figure 5. Kosher and halal status of sweeteners.
A common approach to mitigating the bitter aftertaste of saccharin tablets is the addition of potassium tartrate (5), a derivative of tartaric acid (Fig. 5), commonly obtained from wine. This can cause problems for kosher certification, since the wine utilized is almost always non-kosher. At the molecular level, kosher and non-kosher wines are of course identical, but we must nevertheless accept the fact that, for believers, such demands have a religious rather than a molecular basis.
For the vast majority of Jewish authorities, tartaric acid is regarded as kosher even when it is isolated from non-kosher wine, provided the crystals have been dried for 12 months. Drying equipment has in recent decades become much more efficient, however, and commercial tartaric acid today will have only been subjected to drying for a few days. The evaluation process thus becomes troublesome for the authorities, and various Jewish scholars, and also certifying agencies, have come to different appraisals of tartaric acid.
For desserts that don’t require cooking, as well as soft drinks, the sweetener Aspartame (6) is generally employed: the methyl ester of a dipeptide of the two amino acids l-phenylalanine and l-aspartic acid. The requisite l-phenylalanine (7) is today prepared synthetically, and should in principle pose no problems. Closer inspection shows, however, that in one step, microorganisms are employed. The synthesis itself leads to a 1:1 mixture of the mirror-image isomers d– and l-phenylalanine. Since only a dipeptide prepared from l-phenylalanine tastes sweet, the mixture is separated, following derivatization, with the aid of microorganisms, making it possible to proceed with the pure l-isomer. The microorganisms themselves are not the problem, since creatures that are invisible to the naked eye classify as both kosher and halal, but their culture medium is also not allowed to contain “impure” materials—which includes fats of impure animal origin.
Industrial chemical production in agreement with the laws of Islamic or Jewish religion puts a considerable challenge on both the companies and the religious authorities. The difficult problems can only be solved through trustworthy cooperation. A kosher or halal certificate doesn’t mean that the product is especially pure from a chemical point of view. Rather it guarantees that all raw materials were kosher or halal and that non-kosher or haram material were not present during the entire production process. In a win-win situation new markets will be opened for the chemical industry and the faithful followers are assured that a second trustworthy authority has overseen the entire manufacturing process.
I wish to thank W. Krüger and R.-E. Kühn from Prignitzer Chemie in Wittenberge, Germany, for suggesting the present article, and for valuable assistance in helping me become acquainted with this fascinating field. I was further emboldened by a female employee at the J. Levine & Co. bookstore on 30th Street in New York City, USA—emboldened when she remarked to me that even for her, as an orthodox Jew, the Jewish dietary laws still proved complicated. I am most grateful to B. Felmberg, member of the High Consistory at the Evangelical Center for Berlin-Brandenburg-schlesische Oberlausitz, to Y. Ehrenberg, Rabbi for the Jewish Community in Berlin, and to the Islamologists A. Zaidan and M. Tatari from Halal Control in Rüsselsheim, all Germany  for their willingness to deal with my many questions, always displaying both indulgence and great patience. I wish further to thank Dr. R. Brinckmann, Berlin-Chemie AG, Germany, and A. Sisson from the Free University of Berlin, Germany.
 M. S. Reisch, Chem. Eng. News 2003, 81(16), 18.
 Rabbi, ist das koscher? Orthodoxe Rabbinerkonferenz Deutschland, Köln 2007.
 Z. Y. Blech, Kosher Food Production, Blackwell Publishing, Ames, Iowa, USA, 2004.
 A. Zaidan, www.halal.de
 K. Kühn, Chem. Unserer Zeit 1974, 8, 97.
 W. Babel, Chem. Unserer Zeit 1996, 30, 86.
 2nd Sure (i.e., Chapter 2), Verse 168, and similarly: 6th Sure (Chapter 6, etc.), Verse 146, as well as 16th Sure, Verse 116 from the Koran, (German Translation: M. Henning, Reclam, Leipzig, Germany, 1980); for English translations, see http://corpus.quran.com/translation.jsp?chapter=2&verse=168, and http://corpus.quran.com/translation.jsp?chapter=6&verse=146.
Prof. Klaus Roth
Freie Universität Berlin, Germany.
The article has been published in German in:
and was translated by W. E. Russey.
Unusual interface between chemistry and religion, drawing upon examples from Islamic and Judaic law
R.-E. Kühn and W. Krüger, Germany, talk about the challenges of becoming a certified producer of kosher and halal materials
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