"Are Genetically Engineered Foods in Accord with Jewish Law?"
Steven M. Druker
Alliance for Bio-Integrity
Permission to reproduce is granted provided that authorship is properly
In recent years, the biotechnology industry has launched a massive
enterprise to genetically reconfigure a large portion of the
world's food supply. Hundreds of genetically altered crops and
animals are being developed in laboratories, and already
several varieties of such foods are on grocery shelves (unlabeled). In
most cases, biotechnicians transpose a gene from one
species into organisms of another to endow them with a trait they do not
ordinarily possess (e.g. human growth gene into
salmon to increase their size; flounder gene into beets to make them
cold resistant; bacterial gene into corn and potatoes to
make them pesticidal). Because this technology is growing so rapidly,
because it could in many respects be irreversible, and
because an increasing number of Jews (including many rabbis) are
concerned that its products are unkosher, it is important
there be a comprehensive examination of genetically engineered food in
relation to Halakha so that, if necessary, prompt action
can be taken to secure labeling and protect Jews from being unknowingly
subjected to a broad influx of these altered foods.
From the perspective of Jewish law, there are two basic questions
regarding genetically reconfigured foods, the second more
general than the first.
Question #1: Do foods that are ordinarily kosher become unkosher
when implanted with genes from unkosher
Question #2: In the context of food production, does the artificial
transfer of genetic material between species that
are naturally prevented from crossbreeding constitute a violation of
Halakha (even if both species are kosher)?
Although these are separate questions involving separate sets of
considerations, analysis reveals that each case involves
significant violations of halakhic principles and that the most
reasonable conclusions are:
- . Organisms implanted with genes from non-kosher species are
themselves non-kosher and must be avoided.
- For purposes of food production, transposing genes between
species that are naturally prevented from cross-breeding is a
high-risk venture that is halakhically unsound (even when both species
are kosher). We Jews should speak out against this
practice, and we have strong reason to reject its products on religious
The following paragraphs systematically present the analysis that
leads to these conclusions. (It is important to note that this
analysis is specifically concerned with genetic engineering in the
production of food. It does not deal with genetic engineering in
fields such as medicine, which, as will be discussed, is a distinct
topic with different considerations.)
Question 1 : What Is the Effect of Genetic Transfers from Non-Kosher
This question involves six important issues (or sub-questions).
- Is it significant that the substances produced by transposed
genes generally comprise less than one part in sixty of the
- B. Is it significant that the transplanted genes are merely copies
of the animal's genes and do not constitute direct transfers of
- C. Is it significant that the transfers involve submicroscopic
quantities of matter?
- D. Is it significant that these substances are produced within an
otherwise kosher organism?
- E. Are the medical transplant rulings relevant to transgenic foods?
- F. Are there either special benefits or especially high risks that
need to be considered?
Conclusion Regarding Genes from Prohibited Species
- Does the "One in Sixty" Exemption Apply?
In some cases, Halakha excuses a non-kosher additive that amounts to
less than one part in sixty of the resultant mixture.
However, this exemption only covers instances in which the non-kosher
ingredient was added accidentally. Further, it is
inapplicable when the minute ingredient induces a perceptible effect.
Accordingly, the exemption does not apply to the case of
genetically engineered food, where the questionable substances are
intentionally transferred and produce effects that are clearly
observable (as will be discussed).
- Is There a Difference Between Animal Genes and Their Laboratory
Some rabbis have argued that because the DNA implanted within the
target organism was not itself directly extracted from
non-kosher animals but is merely a laboratory copy of an animal gene,
there is no tissue transfer and no halakhic problem. This
argument, though initially appealing, loses its force in light of the
fact that genes are continually being copied within every living
organism. Organisms grow through cell division, and each time a cell
divides (becoming two cells), all of its genes are copied.
Since the new copies function in the same way as do the genes from which
they were replicated, there is no essential difference
between them. That is how the organism's integrity is maintained as
new cells augment and replace the old. In an adult animal,
every gene is a copy derived from one original set, and most are
products of many generations of copies.
Further, genes are important not in terms of the amount of matter
they contain but in terms of the information they encode.
Genes comprise a minuscule fraction of an organism's matter. They
are sequences of information that direct the development of
the organism's structure and bulk, but in themselves they contribute
little to either. Gene replication is primarily the replication of
an informational code, not the accumulation of bodily mass. Moreover,
this code is operative within any cellular medium --
whatever the species. As long as a laboratory copy fully replicates the
structure of a particular gene, that copy can produce the
same substances as its counterpart, whether implanted back within its
native species or transplanted into a foreign one.
Therefore, the key consideration regarding transplanted genes is not
the extent to which they themselves constitute the
substance of non-kosher animals, but the extent to which they create it.
This will become more evident in the following
- Does the Exemption for Microscopic Phenomena Apply?
In modern times, Halakha has developed a rule that microscopic
phenomena need not be considered in determining the
kosher status of foods. Since genes are submicroscopic entities, it
might seem (at first impression) that embedding genes from a
non-kosher animal in a fruit or vegetable is halakhically irrelevant.
However, analysis indicates otherwise.
In the typical case of admixture, microscopic ingredients cause no
discernible effects. For instance, if a microscopic amount
of pig tissue is blended into potato soup, both its presence and its
effects remain microscopic. The tissue is inert. It does not
itself grow, nor does it induce the growth of other porcine substances.
In contrast, a gene that is engineered into a living organism
remains dynamically lively. It is present within every cell, and it
replicates with every instance of cell division. Moreover, these foreign
genes continually induce the synthesis of proteins (and
frequently other substances) that are typical of their native species,
not the host organism.
Such foreign materials are present in macroscopic quantities. For
instance, when soybeans are engineered with a gene from
a brazil nut to endow them with a specific protein, that protein is
present at the same levels as each of the various soy proteins.
If we were to isolate all the nut protein from a pot of engineered
beans, we could see it with the naked eye. Further, the
protein's effects are also readily observable, even in a sample of
a few beans. Individuals allergic to brazil nuts suffer reactions
when they eat the modified soy.
In addition to their sometimes allergenic or toxic effects, the
products of transposed genes often cause clearly visible changes
within their host. For example, tobacco leaves engineered with a
particular gene from a firefly actually glow in the dark. In
principle, every transgenic food could likewise be engineered to exhibit
a novel, readily visible physiological feature
characteristic of a foreign species. In practice, unless such a feature
is economically desirable, genes that yield less conspicuous
attributes will be employed. Yet, these attributes are still observable,
whether the allergic response of humans to nut protein in
soybeans or the fatal response of worms to corn with a
pesticide-producing bacterial gene.
It therefore seems unreasonable to condone the implantation of
non-kosher genes as a purely microscopic phenomenon
while ignoring both the macroscopic substances they produce and their
clearly observable effects. After all, if a microscopic
dose of a particular chemical was lethal, Halakha would forbid the
consumption of any food containing such a dose (under the
rule that life-endangering substances are not to be eaten). Just as
Halakha acknowledges the relevance of any such microscopic
dose due to its significant effect, so it should recognize the relevance
of the transposed genes. In fact, the case of transposed
genes is even more compelling, since they not only induce a significant
effect (like the lethal dose of chemical) but they do so by
producing visible quantities of non-kosher substances (which the
chemical does not).
A hypothetical example more fully illustrates the logical
inconsistencies that arise from attempting to apply the microscopic
exemption to transgenic organisms. Suppose we create a strain of lentils
containing (in every cell) a pig gene that synthesizes a
structural porcine protein. We cook a pot of these lentils, and then we
extract all the pig protein. This yields a visible quantity.
Then we take an equal portion of lentils, grown without a pig gene, and
cook them in a second pot. We next isolate an equal
amount of the same protein from pig tissue, sprinkle it into the pot,
and stir the contents thoroughly. This renders the second pot
of porridge unkosher, since we've mixed a visible quantity of pig
protein into it. But this seems to entail that the first pot of the
porridge (prior to the extraction) was also unkosher. The first pot
contained the same amount of pig protein as the second pot.
Further, in the first pot, as in the second, the pig protein was an
added ingredient. The only difference is that initially, it was
added via genetic transplant and subsequently appeared inside each
lentil as part of its make-up, while in the final state, it was
added in the manner of a spice.
Moreover, it seems there is no basis to exempt the protein on the
grounds it is merely an isolated chemical compound.
Halakha holds that if either lactose (a milk sugar) or casein (a milk
protein) is present (in isolated form) in an otherwise
non-dairy mixture, they retain their dairy character and the mixture
cannot be served with meat. This entails that isolated pig
protein retains its porcine character.
- Does It matter that the host organism belongs to a kosher
So if proteins from non-kosher animals in transgenic fruits and
vegetables are to be condoned, it will have to be on the
grounds that they were generated within an otherwise kosher organism.
But such grounds are shaky. For instance, if a fertilized
pig ovum were implanted within a cow's uterus and the resultant
piglet successfully brought to term, it's doubtful Halakha
would deem it kosher, even though it was produced within a kosher animal
and the initial transfer from a non-kosher species
was at the microscopic level. Further, in light of the rulings on
lactose and casein, generating the isolated proteins of a
non-kosher animal instead of the entire animal does not in itself
preclude halakhic concern.
It seems the only way to exempt transgenic foods is to argue that
when foreign genes have become embedded in the host
organism's cellular nuclei to the extent that their products are
synthesized by its cellular machinery, these products effectively
belong to and are characteristic of that organism rather than their
source species. (This argument has been advanced by biotech
proponents and largely accepted by the authorities at both the Orthodox
Union and OK Labs.) However, attempting to
conceptually sever the link between a species and its transplanted genes
runs afoul of the facts. Consider a virus, a strand of
DNA that has no surrounding cell of its own and is dormant until it
invades the nuclei of another organism's cells and
appropriates the cellular mechanisms. Many viruses even insert
themselves into the host's DNA strand. Only within and by
virtue of the host's cells can a virus synthesize its proteins. Yet, it
would strain the bounds of logic to argue that these proteins
are those of the host organism. Although they are produced by genes
operating within the organism's cellular nuclei and making
use of its cellular resources, they do not belong to it. They are
debilitating and often life-endangering to the host, and its immune
system recognizes them as a foreign threat and strongly counteracts
Therefore, we can only deny the connection between a species and the
products of its transplanted genes if we are also
prepared to deny the concept of viral infection. If we treat proteins
from pig genes implanted in apples as those of an apple and
not of a pig, we must also declare that a virus-infected apple is merely
undergoing an adverse reaction to its own proteins. We
would further have to say that when NIH researchers spliced the AIDS
virus into the genome of mice, the subsequent suffering
of their offspring was entirely due to a hereditary defect in mouse
Moreover, not only can the products of implanted genes be perceived
as foreign by their host, they continue to be
recognized by members of the source species as their own. That is why
pigs whose organs are destined for transplant in
humans are engineered with human genes that cause their organs to be
coated with molecules characteristic of humans. This
reduces the likelihood that the human physiology will reject the organ
as a foreign intrusion.
Finally, repudiating the relationship between products of transposed
genes and their source species would negate the
possibility of effective labeling. For instance, the FDA has determined
that known allergens, like brazil nut protein, must be
labeled when they occur within a transgenic food. But if a pig protein
in engineered soy beans is classified as soy-sourced rather
than porcine, then brazil nut protein would have to be treated the same.
This would entail the paradox that although soy beans
with brazil nut genes provoke allergic response in people sensitive to
brazil nut protein, identifying them as containing this
protein would be a case of mislabeling.
Thus, if Halakha is to do justice to biological reality, it cannot
conceptually disassociate proteins from the genes that produce
them and genes from the species that naturally harbor them. The products
of genes transposed into foods continue to express
essential attributes of their native species and are clearly
distinguishable from those of their host -- as is amply indicated by the
examples of glowing tobacco, pesticide-producing corn, and beans that
aggravate brazil nut allergies. Only by ignoring such
facts can kinship be contrived between an organism and a distinctly
foreign gene that's forcibly inserted within it.
- Are the Medical Transplant Rulings Relevant to Transgenic Foods?
The halakhic rulings that have permitted transplant of tissue from
non-kosher species into humans do not readily apply to
genetically engineered food. For one thing, such transplants can be
justified on the basis that death or serious impairment would
otherwise result. Accordingly, the ruling that a transplanted organ
becomes part of the host must be seen in this light and should
be limited to such extreme circumstances. Classifications of kosher
versus unkosher food cannot be properly made in such a
context, since when life is clearly at stake (e.g. one is starving),
eating non-kosher food is permissible. Therefore, just because
Halakha treats a pig intestine transplanted into a critically ill human
being as part of that person's physiology does not entail that
it should treat pig proteins engineered into apples as fruit protein.
Further, even though transplanted organs can, for some medical
purposes, be viewed as part of the host organism, there are
other contexts in which Halakha would probably treat them as
representative of their source. For instance, if a pig liver were
transplanted into a cow, which a month later was slaughtered, it's
doubtful the liver could rightly be sold as kosher.
- Are There Special Benefits or Especially High Risks?
Do genetically engineered foods have such life-saving potential that
they can be accepted on the same basis as transplanted
organs? While there are some medical applications of genetic engineering
that might well be condoned under this principle, it's
difficult to make the case that genetically altered food products should
be as well. Although proponents of the process claim it
can avert famines and significantly improve the general level of
nutrition in the Third World, many scientific experts (several of
them from the Third World) disagree with the projected level of benefits
and instead emphasize the high level of risks
associated with this new and relatively untested technology. Some of
these risks are unique to genetic engineering, such as the
irreversibility of many of its effects. The potential scale of this
irreversibility has been termed "awesome" by Erwin Chargaff,
often referred to as the father of molecular biology.
In the next section, which more thoroughly examines risks and
benefits, it will become clear that the use of genetic
engineering in food production is a far different matter than its use in
medicine and cannot at this stage of our knowledge be
categorized as a necessary health measure. Accordingly, the non-kosher
admixtures it produces cannot be exempted on such a
Therefore, in light of all the above considerations, it seems most
reasonable to conclude that genes transposed from
non-kosher species into otherwise kosher ones will, through the products
they synthesize, imbue their host organisms with a
non-kosher character. However, there is still the question of whether
cross-species gene transplant for purposes of food
production is in itself contrary to Halakha, even when it's
restricted to kosher organisms.
End of part 1
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