Question
I recently heard about a new technology developed in Israel that produces milk proteins using plant- and fungus-based sources. The resulting proteins are said to be physically identical (or nearly identical) to those found in real cow’s milk. From a halachic standpoint, would these lab-generated milk proteins—and the foods made from them—be considered kosher? And if they are kosher, would they be classified as dairy or pareve?
Reply
To understand the halachic status of this new milk alternative, it helps to first understand how it is produced.
Unlike plant-based milks, which only simulate dairy by blending or soaking oats, nuts, or soy beans, this new method uses a process known as precision fermentation.
In precision fermentation, microorganisms—like yeast or fungi—are engineered to produce real dairy proteins. Scientists identify the cow’s gene for a specific milk protein, chemically synthesize and copy that DNA sequence in the lab, and insert it into the microbe so it becomes programmed to make that protein. The microbes are then grown in large fermentation tanks and fed sugars, and as they multiply, they naturally produce the target protein. Afterward, the microbes are filtered out, and the purified protein—chemically identical to whey or casein from cow’s milk—can be used to create dairy products without involving any cows.
Over ten years ago, in an article titled Is Lab-Grown Meat Kosher?, we discussed the then-emerging question regarding the status of lab-grown meat. However, there is a critical difference between how the two are created.
Whereas cultivated meat is produced from actual animal cells, which remain present (albeit minutely) in the final product, lab-grown milk is created by inserting a synthetically produced gene into a microbial organism, such as yeast or fungus. No actual cells from a cow are used in the production of the product.
Based on this distinction, although kosher-certifying organizations generally consider lab-grown meat to be meat (and kosher if it originates from a kosher animal), this lab-made milk is not milk at all. From a halachic perspective, just because something tastes like milk or meat does not mean it is treated as such if it is not, in fact, real milk or meat.1
Moreover, milk found in a cow’s udder after it has been slaughtered in a kosher manner—even though it is biologically the same milk that would have emerged naturally—is not biblically2 considered milk, since it never actually left the udder.3 How much more so with this new “milk,” which does not come from a cow at all!
Based on the above, while any components used must obviously be kosher, this new milk is most likely not considered halachically dairy but pareve. Nevertheless, there are still a number of considerations to keep in mind.
What Will People Think?
There is a concept in Jewish law called mar’it ayin (lit. “appearance to the eye”). Certain permitted acts are prohibited simply because observers may mistake them for other, forbidden acts, leading them to either believe that the act is in fact permissible or to view the person negatively. Generally, even if something is forbidden only because of mar’it ayin, it may not be done even in the privacy of one’s home.4
However, since the reason for this prohibition is only because of how the act can appear to others, if one takes certain necessary precautions, the act is permitted.5
A classic example is drinking almond milk with a meat meal: this is permitted only if it is obvious that the milk is non-dairy, such as by leaving the clearly labeled container on the table.6
The same applies to this new alternative milk, perhaps even more so than with the current milk alternatives. Since its proteins are chemically identical to dairy, and the final product looks, pours, and cooks like real milk, using it with meat could easily be mistaken for mixing milk and meat. The same applies to cheese produced from these synthetic dairy proteins, which may be visually indistinguishable from regular cheese. In such cases, you would need to clearly indicate that the product is non-dairy—either by keeping the packaging visible or using another obvious sign—so that onlookers are not misled.
Allergens
Another consideration, noted by both kashrut and government organizations, is that while these new dairy products are lactose-free and therefore suitable for those who are lactose intolerant, people who are allergic to dairy proteins (rather than lactose) are likely to react to this new milk as well.
This raises the question of labeling: from a halachic perspective, the product may be pareve, but from an allergen perspective, it may still behave like dairy.
Other Ingredients
Although this new product may be considered pareve on its own, when it is used in manufactured foods, other ingredients—potentially including actual dairy—may be present. While the product mimics milk in taste and texture, it is still different from genuine milk. Therefore, it is important to verify not only that the product has proper kosher certification, but also whether it is considered dairy or pareve. For example, this author knows of at least one product that uses this synthetic milk but is still designated as dairy because of other dairy-derived ingredients it contains.
Dining and Cooking