Biotechnology: is it kosher?

By M. E. Siddall

Three rabbis walk into a bar… -coding lab.

I had received the worried call from Rabbi Chaim Loike of the Orthodox Union only a few days before. Increasingly of late, congregants had been reporting worms in their fish – mostly canned sardines and fish eggs – notwithstanding that all had been certified as Kosher Pareve by the Orthodox Union.

Have a look at the tins of sardines or tuna in your cupboard, or on the grocery store shelf. It’s very hard to find any, regardless of brand, without some mark of kosher certification. The overwhelming majority will have that from the Orthodox Union: Ⓤ. It’s not just tins of fish. Right across the aisle from the sardines in my local grocery store are the boxes of dry pasta, each with the coveted Ⓤ symbol. (Pro-tip: don’t look for it on tins of smoked oysters or lump crab meat).

Like the FDA, Orthodox Union certification was born out of the industrial era’s shift from agriculture. Technical advances in canning allowed foods to be eaten far from the field during any season. In 1824, the first mass-produced preserved food in France was tinned sardines from Joseph Colin’s cannery in Nantes. Kosher certification pre-dates the FDA itself by a few years, but the motivation was the same: adherence to standards. Specifically, adherence to Kashrut Law for the OU, and adherence to food safety for the FDA – quite obviously complementary notions.

Orthodox Union kosher certification was founded in 1923 by Abraham Goldstein (who lived where I do now in Manhattan’s still vibrantly Jewish Hudson Heights). But it was Betty Goldstein (no relation) of the OU Women’s Branch, who first worked to “persuade some of the well-known manufacturers of food products to substitute kosher for non-kosher ingredients.” This prompted OU President Rabbi Herbert W. Goldstein (no relation to either), to launch the organization’s program of systematic kosher supervision.

Their first cooperative agreement was with the Heinz corporation when Goldstein (Abraham) first applied the distinctive Ⓤ to Heinz’s baked beans in 1923. By 1925, fully 25 of Heinz’s “57 Varieties” were declared kosher through their collaborative relationship. The next year, the Orthodox Union inaugurated a kosher dining facility at Harvard in 1926, and by 1935, Abraham Goldstein had fully established the Kashrus Laboratory for OU certification.

That was all well before the Food, Drug, and Cosmetic Act finally allowed the FDA to impose labelling certifications on food when it was signed by FDR in 1938. My talented friend Deb Blum has done a terrific (and entertaining!) job of describing the prelude to, and origin of, the FDA under Harvey Washington Wiley in “The Poison Squad”. In the time since, more than a thousand other kosher certification agencies have been established, but the “Big 5” remain OU, OK, KOF-K, Star-K, and CRC, all trusted on an international scale by the kosher-observant and the halal-observant alike.

Rabbi Chaim arrived in the morning with dozens of cans of sardines, half-pints of fish roe, a bag of thawing pilchards threatening to exude pungent drips, and two rabbinic colleagues. I wasn’t entirely prepared for a first-name basis with these august arbiters of Jewish law, but we got past formalities promptly.

“Dr. Siddall…”, Rabbi Chaim began.

“No, no, call me ‘Mark’”, I stopped him.

“… OK. Good.” He continued, “let me introduce you to my colleagues from the Orthodox Union: Rabbi Chaim…”

“Ah, another ‘Lifer’?” I quipped and shook his hand as he chuckled.

“… and Rabbi…”

“Don’t tell me…”, I joked, “Chaim?”

“Yes, in fact”, replied the third rabbi.

“You have no idea how much mileage I’m going to get out this gentlemen! Please follow me,” I said as I led them to my wet-lab.

So long as they have visible scales, fish hold a special cross-over place in Kashrut dietary law. They are considered neither “meat” nor “dairy,” but rather “pareve”. Like other pareve foods, including fruits, vegetables, grains and eggs, fish can be consumed with what is considered either meat or dairy. For the observant consumer this creates tremendous flexibility for nourishment in uncertain circumstances, especially travel (voluntary or involuntary). For the food industry too, there’s a wider utility, appeal and demand for pareve products – like “O” universal donor types.

So, there was a lot at stake with what the 3 rabbis, I and my students were trying to solve. Losing kosher certification from the OU would be extremely financially damaging to Brunswick and Bumble Bee alike. You might think that the mere fact of parasitic worms in your tuna or tobiko would be sufficiently damning. Not so.

Rabbi Chaim explained that “the Talmud, though written 2,000 years ago, described a number of worms, which, even though they’re not something you would want to eat, if they were accidentally consumed, would still be kosher.” However, if the worm comes from the intestines, it’s not kosher as it is evidence that the fish have not been prepared according to kashrut guidelines preventing guts from contaminating the flesh of the fish. “However,” he added, “if a worm is found to have grown its entire life in the flesh of the fish, it is considered to be the same as the fish. And therefore, it’s kosher.”

As a parasitologist, I can affirm the genius of this. Should any worm in a fish render that fish off-limits, there would be no fish at all in the Kosher diet. (Sorry for the revelation to fish lovers everywhere, it is for this reason that there’s no such thing as fresh-never-frozen sushi). Typically, these larval worms are of no concern whatsoever to diners because humans are not the appropriate hosts for the parasites. However, there are exceptions. 

I explained to the Rabbis Chaim that worms found in the roe, the canned sardines, and the now redolently thawed and soggy pilchards, could be identified through DNA sequencing with a form of genotyping that had become known as DNA barcoding. That is, any worms that had come from the gut of the fish would be adults, and from a certain range of species. Similarly, other nematode worms that are normal occupants of the fish muscles would only be larval stages and from different species of worm. Which is to say that nematode parasites kosherly hanging out as larval stages in fish tissues, only achieve their adult gut-dwelling forms in mammals, birds, or larger-than-a-sardine fish after eating a hapless herring.

Any kind of genotyping requires not only DNA information from something of interest (“perp” or parasite), but also a reference database for comparison. In CSI-style forensics, the DNA data are specific letters at specific sites in human DNA called “SNPs”, and the reference database is a comparable set of SNPs from known offenders in CODIS that is maintained by the FBI. (Recently, and controversially, samples have also been compared to genealogy databases containing SNPs of unwitting relatives of known offenders).

That is far too fine a scale than is necessary for identifying species. Instead, for DNA barcoding, there has proven to be remarkable cooperation among communities of biodiversity scientists in terms of agreeing on what gene or genes should be used to identify species. A good example is the ubiquity with which the cytochrome oxidase (cox1) gene is used to identify animals on continental scales, or what’s really on the menu in your favourite seafood restaurant. 

It turned out, much as I had suspected, the parasitized pilchards as well as the rest of the putatively pareve provisions harboured nematode species that would only be present as immature larval stages in natural tissue locations. Nobody was forced into bankruptcy through loss of their Ⓤ certification. It seems, and perhaps due to climate change, there had been a “bump” in the prevalence and intensity of infections among fish in the Mediterranean where they had been sourced.

Not only did we squeeze a peer reviewed publication out of this work applying biotechnology to a socially and commercially relevant task… the Rabbis Chaim did as well (below). 

A few weeks after our paper came out, I received an email from another rabbi. He asked whether the larval stages do not themselves migrate from the intestines to the flesh of the sardines which would deny their permissibility since they do not form in the fish muscle itself and so cannot be of the fish itself. I explained that yes they do since there’s no such thing as spontaneous generation, but that I had no expertise on any Talmudic implications.  Panicked, I forwarded all to Rabbi Chaim. He replied, “You’ve never heard the phrase ‘Two Jews, three opinions‘? How many rabbis now? Four? Don’t sweat it.”