Kosher Pork and Treif Tomatoes
Miryam Z. Wahrman, Ph.D.
When a local kosher fast-food restaurant opened a few years ago, they offered a kosher "cheese-burger" (made with ersatz cheese), and they dubbed it a "gevina-burger". The idea of eating a heretofore taboo combination was intriguing to me so naturally I ordered one. As I gingerly picked it up to take a bite, my stomach did a flip-flop, and the taboo was so strongly ingrained that I was unable to enjoy the combination. Modern food science had produced a fake cheese, which wasn't very cheesy, but it allowed the Orthodox consumer to experience a new taste sensation. Apparently others may have felt as I did, as this dish was soon discontinued.
Cutting-edge science may now afford us the opportunity to create other new foods for our kosher tables and some of those foods may revolutionize the choices available for the kosher consumer. Genetic engineering allows scientists to manipulate the traits of many different types of organisms, including plants and animals, producing organisms with new and novel traits that have not previously been encountered within a particular species. Plants and animals which have been genetically altered in this way are called "transgenic".
The first transgenic animal ever produced was a laboratory mouse whose fertilized egg was injected with a rat gene for growth hormone. When the gene was turned on, it enabled the mouse to grow significantly larger than a normal mouse. The mouse was dubbed "Mighty Mouse". Other more recent experiments on animals involve the genetic engineering of farm animals. Transgenic goats are produced by injecting goat embryos with specific genes. Some of these animals produce pharmaceutical drugs, like t-PA (tissue plasminogen activator), which is used to treat heart attacks. Scientists can harvest those products from the goat's milk, and purify them to produce relatively low cost drugs.
Novel plants which have been produced through genetic engineering include a tobacco plant which expresses a firefly gene. The leaves of the plant literally glow in the dark. This was the first experiment to successfully produce transgenic plants. In this case, the firefly gene was used as a marker - simply to show that it was possible to alter the traits of the plant; not, as one might imagine, to make a cigarette which lights itself.
The so-called "Flavr-Savr" tomato, which can ripen longer on the vine and still be shipped without rotting, was the first transgenic plant to be approved by the Food and Drug Administration. Other novel plants produced by genetic engineering include virus-resistant squash, herbicide-resistant soybean plants, potatoes which absorb less oil when fried, and insect-resistant cotton and corn.
When transgenic plants and animals are produced, a specific gene is first identified and isolated from living tissue. The source can be plant, animal, fungus, or a single-celled organism, such as bacteria. DNA - the genetic material - from the donor species is purified chemically, cut into pieces, copied millions of times in the lab (either in a bacterial cell, or by chemical methods), and the resulting purified, amplified gene is transferred to a recipient species to alter the genetic program.
The donor species provides DNA sequences, the genetic information, which encodes a particular trait. The recipient species must accept the DNA, and link the genetic information to one of its own chromosomes so it becomes part of its own genetic program. In order for the process to work the genes must be intact and be able to be turned on in the recipient. Creating a transgenic plant or animal is therefore not a simple task to accomplish. Since our understanding of gene action is far from complete, frequently the procedure is unsuccessful. Because of the difficulties involved, and the expense and time needed to succeed with such projects, genetic engineering is not done for frivolous reasons; there must be a very compelling reason to try to change the genes of an organism, and hence its traits. The justification for such experiments include clinical, environmental and nutritional applications.
Although there are so many potential technical difficulties, and the monetary investment may be initially high, genetic engineering to produce transgenic plants and animals has become quite important in the commercial world. New genetically engineered species of plants are already being sold in supermarkets. FDA regulations do not require the labeling of foods which have been genetically altered, so we may be consuming these products without our knowledge. Since we are already most likely eating products of genetic engineering, an important question for the Jewish consumer is: How do these new genetically engineered foods impact on the Kosher dinner table?
Plants, in fact, all things that grow from the earth (including mushrooms, which by scientific definition are fungi, and are quite distinct from plants), are considered to be kosher. Now it is possible to genetically engineer plants, and introduce a variety of different plant and/or animal-derived genes into plant species.
For instance, there are species of plants which have been genetically engineered to be frost-resistant. This has been accomplished by extracting the genetic material, that is, the DNA, from Arctic fishes. The DNA is isolated and purified, copied millions of times in the laboratory and inserted into plant cells. The genetic information enables fish that live in the Arctic region and under the polar ice-caps to survive by preventing their blood from freezing. The quality of frost resistance, when introduced into plants, can reduce the risk of crop damage when the temperature drops below freezing. The source of this DNA, that is the Arctic fishes, may not be kosher. In fact, frost-resistance genes can be derived from animals such as penguins, whose feet are frost resistant. Would plants genetically engineered with DNA from nonkosher animals become treif [nonkosher]? If kosher animals, such as cows or chickens, were used for donor DNA would the plants lose their neutral parve status? (Plant foods are considered neutral, neither dairy nor meat.).
An analogy may be made to the ancient process of cheese production. In order to produce cheese, milk is mixed with a minuscule amount of rennet, the lining of a animal's stomach. Rennet contains the enzyme rennin which curdles milk, changing its consistency from liquid to solid. One might imagine that cheese could never be kosher since an animal product is being mixed with milk. "Rennet has lost its identity as food, because it's not edible. It has become a chemical catalyst," explained Rabbi Tzvee Zahavy. "Anything that is not edible for a dog is the threshold. Once it loses its identity as food, it is not governed by the laws of kosher food."
In production of transgenic plants or animals there is no direct transfer of "ingredients" from one species to another during the genetic engineering process. DNA is isolated in the lab, copied by bacteria or by chemical methods, and then inserted into the recipient cell. "DNA is a chemical and wouldn't be edible for a dog," reasoned Zahavy. "It is absolutely not governed by the halacha of food."
What about DNA from a nonkosher animal? According to Zahavy when rennet from a nonkosher animal is used to produce cheese, it does not make the cheese treif. Zahavy, who was ordained by Rabbi Joseph Soloveitchik stated, "Rabbi Soloveitchik used to permit eating cheese from Kraft." He continued, "The whole kosher cheese issue raises logical inconsistencies because if the rennet is still food' and governed by the laws of food, then it is still meat. So no cheese would be kosher." If, on the other hand, rennet is not "food" then its source should not be an issue, explained Zahavy.
Genetic engineering has already produced novel species of plants and animals. Could it result in the production of kosher pork? It may be possible to produce kosher pigs by introducing the physical traits which are defined as kosher. Pigs are treif, or non-kosher, based on the biblical requirement that kosher animals must have split hooves and chew their cud. While pigs do have split hooves, they do not chew their cud. If that species could be genetically engineered in such a way so that it would begin to exhibit all traits required for kashrut, would observant Jews be allowed to eat the meat of that transgenic pig?
Imagine the culinary possibilities of kosher bacon, ham and pork. Then again, we may not want to imagine that. The idea of eating pig, even kosher pig, may not sit well with the kosher consumer. Kosher pork may go the way of gevina-burgers. On the other hand, perhaps Moo Shoo Kosher Pork will become the latest rage at kosher weddings and bar mitzvahs and take its place alongside the sushi bars and caviar.
Dr. Miryam Z. Wahrman is Director of General Education and Professor of Biology at William Paterson University of New Jersey in Wayne.