Worm-Infested Sardines II

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As a follow-up to this post (link), I obtained this Q&A of Daf HaKashrus with permission to publish:


The note preceding the sardine article/ R’ Belsky’s teshuva/ stated that the new scientific DNA research proves that as “R’ Belsky Shlita concludes that these are the same anisakis worms which Halachah permits as being Darni D’Cavri. These worms have migrated from the flesh of the fish to its gut. R’ Belsky’s conclusion was scientifically borne out…”. How did the scientific research prove that they migrated from the flesh to the gut and not vice-versa?

Moshe ********

The Daf responds:

Dear Rabbi ********,

We apologize for the confusion caused by the introductory note. You are correct that the DNA research only proves that the worms in the gut of the sardines are darni d’Cavri (permitted flesh worms). It does not directly indicate the direction of the migration. However, Rav Belsky explained in a separate teshuva that anisakis enter the sardines when they eat infected fish (krill). These worms are permitted because they initially become visible inside of these very small fish and as such the worms were never rochesh in the water. Accordingly, the direction of the migration is irrelevant.

We should also point out that the fact that the worms first become visible inside of the fish is only a suggested explanation for the heter. The reason for the absolute certainty of the heter is that the Gemara says that darnei d’Cavri are mutar and the Shulchan Aruch says that worms in the flesh are mutar. If anisakis is assur then there are no worms in any fish that are mutar and this is against the Gemara and Shulchan Aruch.

About Gil Student

Rabbi Gil Student is the Editor of TorahMusings.com, a leading website on Orthodox Jewish scholarly subjects, and the Book Editor of the Orthodox Union’s Jewish Action magazine. He writes a popular column on issues of Jewish law and thought featured in newspapers and magazines, including The Jewish Link, The Jewish Echo and The Vues. In the past, he has served as the President of the small Jewish publisher Yashar Books and as the Managing Editor of OU Press. Rabbi Student currently is serving his third term on the Executive Committee of the Rabbinical Council of America and also serves as the Director of the Halacha Commission of the Rabbinical Alliance of America. He serves on the Editorial Board of Jewish Action magazineand the Board of OU Press. He has published four English books, the most recent titled Search Engine volume 2: Finding Meaning in Jewish Texts -- Jewish Leadership, and served as the American editor for Morasha Kehillat Yaakov: Essays in Honour of Chief Rabbi Lord Jonathan Sacks.


  1. I find the OU’s answer to the question on the anisakis ruling to be unsatisfactory. The only scientific evidence referenced in the prior post on anisakis in sardines is that the worms in the gut had the DNA signature of the anisakis. The identity of the permitted worm species in the flesh of fish, darni (T.B. Hulin), is still not established, however. Perhaps the gemara in Hulin refers to another fish parasite. Nor is evidence produced that the juvenile form of the anisakis worm that is ingested by the half-inch krill crustacean is microscopic. That form of the worm would have to be considered too small to perceive by eye in order to possibly remove it from the forbidden category of sheretz hamayim.

    More generally, the implication of the prior post is that the OU gives hashgacha on intact sardines. Why would a kashrut organization certify a brand that contains gut contents when such material may well contain undigested shratzim, such as crustaceans, that are clearly forbidden?

  2. The krill are certainly visible, but the larva in no way is. True the OU didn’t mention a source, but you can look them up in a biology textbook.

    I agree about the rest of the points, though. Anisakis is most likely darni, but who can say for sure.

  3. What is the actual frequency of these worms? If 0.1% of sardine tins contain a worm in one of the sardines, I would think the sardines are mutar lechatchila, even if the worms are of a forbidden kind.

  4. I made the point in a lecture on this subject before RYB issued a ruling that the permission of consuming fish with worms in the flesh was not a scientific issue but whether such a creature was prohibited by the Torah. I compared it to organisms that teem in a kli. However, in no way should these fish or worms be eaten because of the rabbinic restrictions of baal teshaksu and that eating a parisite was never a good idea.

  5. “However, in no way should these fish or worms be eaten because of the rabbinic restrictions of baal teshaksu and that eating a parisite was never a good idea.”

    The poskim are clear that (for example) it is acceptable to drink from bodies of water containing insects that do not meet the Torah’s standards for prohibition. They do not mention an additional issue of “bal teshatzu” in these cases, and evidently one does not exist.

    We have enough problems with people on the left wing who invent intellectually dishonest leniencies; how can we credibly debate them when we ourselves insist on inventing intellectually dishonest stringencies?

  6. I think a lot of factory-farmed animal products are disgusting and “never a good idea” to eat. Now I can tell everyone that they are assur too?

  7. Gedalia,
    It is not clear that eating a parasite is never a good idea. See some the recent reseach in treatment of Crohn’s disease by ingesting parasites.

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