A Change For The Better: Nishtaneh (Change) in Kosher Law

OU Kosher Staff

The month of Elul is about changing ourselves, learning to step out of the straits of routine and develop a new identity of who we are and what we can accomplish. Elul is therefore a time to reflect on an age-old halachic question: when a non-kosher ingredient is radically modified and becomes, essentially, a new substance (nishtaneh), does it remain assur? Or is it a new entity, without yichus to the original issur?

This question has taken on a modern spin in the last few years because of new technologies used to produce ingredients. In particular, global ingredients manufacturers have been producing more and more ingredients using a biochemical processes that take abundant, inexpensive ingredients and converts them to more valuable, specialty ingredients. The process is called fermentation, and many of the ingredients that are in the processed foods we buy are the result of it.

We are familiar with fermentation when we notice that wine, left out, or uncorked for a few weeks in the refrigerator, turns to vinegar, or grape juice becomes wine. In both of these cases the change that occurs is the result of the activity of microorganisms, which are not visible to the eye, on the juice or wine. The microorganisms change the chemical structure of the substance — the juice or the wine — off of which they are feeding.

As biochemists and food scientists have learned more about how microorganisms work they have managed to exploit this biochemical process to produce new ingredients that either were never before available or were never available in the enormous volumes they are now. If a company selects the right microorganisms and then provides an environment for the microorganisms to proliferate, these microorganisms are capable of converting, on an industrial scale, the relatively cheap foodstock that is given to them and produce from it an utterly new ingredient. In many cases, the new ingredients are dramatically different from the original feedstock. Although grape juice tastes and looks somewhat like wine, and wine tastes and looks somewhat like wine vinegar, some of the industrial fermentation processes create ingredients that are absolutely unlike the original material used in the fermentation.

Such a change was the result of research carried out in the 1950’s by government scientists in the United States. They were given a mandate to find ways of making valuable the abundant amount of cheap corn syrup that American farms and corn refiners were producing. They set about looking for various ways to ferment corn syrup and produce value-added ingredients. One of the projects they worked on developed from their observation that slime on a lily pad, when added to a food system, had some easily-appreciated capabilities: the slime (which in their language is called a polysaccharide) could act as a “gum” in the foods, providing structure and body to foods that may otherwise, over time, begin to fall apart. The gum, it was discovered, could also retain moisture, and therefore it could be used to maintain a food’s freshness.

The slime that develops on a lily pod is the result of microorganisms that were eating, and converting, the lily pod to the slime that they found so useful. The scientists identified the particular strain of microorganism that was so adept at making this gum. They harvested massive amounts of these microorganisms, designed diets especially for them and constructing huge tanks to house their growth, carefully calculating ways to maximize their proliferation. Once enough of these microorganisms had proliferated instead of giving them lily pods they fed them, instead, corn syrup. The massive numbers of microorganisms would convert even more massive amounts of corn syrup into the substance they had originally identified as the slime on the lily pod. The ingredient is called xanthan gum, and it remains a popular ingredient. It keeps our cream cheese moist, thickens our salad dressings, and adds body to ice cream.

Now, xanthan gum bears absolutely no resemblance to corn syrup – it doesn’t taste like corn syrup or behave like corn syrup, and there is no plausible way that one could call it corn syrup. Is it, halachically, corn syrup? This question is relevant to Pesach, where Ashkenazim have a minhag to refrain from eating kitniyot including corn and many also refrain from eating corn-derivatives.

What if the xanthan gum were produced not from corn syrup, which is generally free of kosher problems, but from whey, which is a milk derivative and which can suffer from a host of kashrus problems? In fact, a 1995 patent recommended using whey as a feedstock, instead of corn syrup, for the production of xanthan gum. Would the xanthan gum still be considered b’dieved, pareve? Could it be considered kosher? Is “xanthan gum” sufficiently different from whey, to be free of all of the non-kosher questions associated with whey? Is it whey?

The growth of biotechnology in food production has generated similar ingredients that similarly experience radical changes. Many of these are “household” ingredients that may not be stocked in our cupboards but are present in the processed foods we buy. Citric acid, which gives the sweet, tangy taste to gummy bears, is produced by fermentation in a process similar to the production of xanthan gum. Monosodium glutamate, which is used as a flavor enhancer in various foods is also produced by fermentation. Vanillin, which is the characteristic taste of vanilla, is produced from a rice derivative.

The question of when an ingredient is nishtaneh (changed) and becomes a new ingredient was the basis of a dispute between the Rosh and Rabbeinu Yonah regarding musk, an aromatic substance that originates from the blood, or other secretion, of the male Musk Deer, the Rosh contends that an ingredient that changes its identity remains assur, and the Rabbeinu Yonah is lenient. The Pri Megadim in Orach Chaim 216 concludes that if the issur is a d’rabbanan, then it is appropriate to be lenient; if the issur is prohibited min haTorah, then it is appropriate to be machmir. The degree to which something must be changed to qualify for nishtaneh was not precisely defined in earlier generations, but some Poskim have noted that both a chemical change and a change in the taste is required (see Teshuvot Shevet HaLevi, 5, 56).

Many of the ingredients produced by fermentation these days meet these criteria and would qualify as nishtaneh. Still, no reputable hashgacha agency permits companies to use an issur d’rabbanan – such as whey, in some circumstances — and convert it in these industrial-sized laboratories to produce something kosher. The hashgachot reason that although the finished product is b’dieved kosher, one should not lechatchila produce or certify such an item.

Nevertheless there are Poskim who hold that as relates to Pesach, it is permissible to accept – and even certify – a kitniyot-based ingredient, like corn syrup, that was radically changed. Ashkenazim who refrain from eating kitniyot on Pesach do so merely because of a minhag, and these Poskim hold that as relates to a minhag one may even lechatchila accept such products as kosher (for Pesach). One famous example where this comes up is in Pesachdik diet soda. One sweetener used in diet soda is aspartame, which at least at some stages is made though the fermentation process, and most of the Pesachdik aspartame is made using corn syrup, based on the aforementioned line of reasoning.

Other Poskim hold that an ingredient can only properly be called nishtaneh if, before it was changed, the ingredient went through a stage where it was inedible — which is apparently true for musk. Since standard fermentation processes do not render the ingredient inedible, even a very dramatic change would not qualify as nishtaneh. Even this position would permit Pesachdik diet soda, b’dieved, because the kitniyot in such a context would be batel.

All Poskim would agree, however, that regarding efforts to change ourselves for the better, anything helps. We should be zocheh to see a change from the bitter times of this past year to a sweet one in the coming year.