Articles

By Rabbi Dovid Cohen, Administrative Rabbinic Coordinator

Q. Someone told me that all canned fruit are okay, but canned vegetables require hashgachah.  Is that true?  What could be the difference between fruits and vegetables?

A. The most obvious issue with canned fruits and vegetables, is that the cans typically contain other ingredients as well.  Water, salt, and sugar do not pose a concern, but it is not unusual for there to be “fruit juice” (which might contain grape juice/stam yayin), colorings, flavors, or other kosher-sensitive ingredients.  For example, the brine used for Kalamata olives traditionally contains wine vinegar.  Clearly, if the ingredients are not kosher, then the canned fruit or vegetable is not kosher.

But in many cases, the more significant issue is that canned foods must be processed at very hot temperatures in a machine known as a “retort”.  The basic idea is that once the food is sealed inside the can, no new microorganisms can get in, and, therefore, if the can (and its contents) are heated enough, any microorganisms and pathogens that are already in the can will be destroyed.  In turn, that means the food will remain fresh indefinitely.  The kashrus issue this raises is that the same retort can be used to process canned vegetables and canned meat, fish, or other non-kosher items.

In this context it is important to explain the governmental separation between two different types of canned food: ones that contain low-acid vs. high-acid foods.  “Low-acid” refers to those foods whose acidity has a pH of 4.6 or higher.  In such an environment, spores (dormant microorganisms which are encased in a strong shell) will eventually begin to grow and produce toxins, and therefore low-acid food must be sterilized to the point that even the spores are killed.  This requires relatively high temperatures for extended amounts of time.  Most vegetables, meats, poultry, pasta, and cheeses, fall into this category, and they would potentially be processed on the same retort.  Hence, canned vegetables, such as corn, peas, carrots, beans, and tomatoes require hashgachah, even if the ingredients are innocuous.

Bearing in mind that all canned items are cooked in the retort, means that we must consider the bishul Yisroel requirement for anything which is canned.  For example, not only do canned potatoes require hashgachah because they may have been processed on a retort which is used for non-kosher (as noted), but certification is necessary to ensure that the cooked/canned potatoes are bishul Yisroel.  Most fruits are edible raw, such that cooked fruits do not require bishul Yisroel.

In contrast, most fruits (including pineapple) are “high-acid foods” (i.e., with a pH that is lower than 4.6) and do not require such extensive processing, as the heat must merely kill the microorganisms (and any toxins which they have already produced) but not the spores.  Retorts used for those purposes are not suited for meat, etc., and are relatively cheap, such that it would not be unusual that it be used just when the local fruit is in season (e.g., peaches) and then left unused for the rest of the year.  [However, a retort that can process low-acid foods costs more and would be used as much as possible for many different foods].  Therefore, canned fruit (i.e., canned high-acid foods) do not require hashgachah, assuming there are no sensitive ingredients or other concerns (e.g., insects, Eretz Yisroel, etc.).

This article first appeared in the Let’s Talk Kashrus column, Yated Ne’eman, May 24, 2024.