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Kosher Issues for Today’s Dairy Industry

by Joe M. and Carrie E. Regenstein

This article has been previously published in the Cheese Reporter (Summer, 2002) and in Cheese Marketing News (September, 2002).

Copyright © 2002 Joe M. Regenstein


Joe M. Regenstein
Professor of Food Science
(Visiting Professor of Food Science, University of Wisconsin – Madison)
Head: Cornell Kosher Food Initiative
Cornell University
Ithaca, NY 14853-7201

Carrie E. Regenstein
Associate Chief Information Officer
Associate Director, Division of Information Technology
University of Wisconsin - Madison

The kosher dietary laws determine which foods are “fit or proper” for consumption by Jewish consumers who observe these laws. The laws are Biblical in origin, coming mainly from the original five books of the Holy Scriptures. Over the years, the details have been interpreted and extended by the rabbis to protect the Jewish people from violating any of the fundamental laws and to address new issues and technologies.

The kosher market includes almost 100,000 products in the US; about 100 billion dollars worth of products have a kosher marking on them. The actual consumers of kosher food, i.e., those who specifically look for the kosher mark of products they purchase, are estimated to be about 6 to 8 million Americans and they are purchasing almost 3 billion dollars worth of kosher product. Fewer than one third of the kosher consumers are Jewish; other consumers include Muslims, Seventh Day Adventists, vegetarians, people with various types of allergies – particularly dairy, grain, and legume allergies – and consumers who simply value the quality of kosher products: “You don’t have to be Jewish to love Levy’s Jewish Rye” and “We report to a higher authority (Hebrew National)” have been very successful ad campaigns and have brought kosher products to the attention of general consumers. AdWeek Magazine once referred to kosher as “the Good Housekeeping Seal of Approval for the 90s.” By undertaking kosher certification, companies can incrementally expand their market. Companies should only undertake kosher production when the profits exceed the costs.

The kosher dietary laws predominantly deal with three issues, all focused on the animal kingdom:

  1. Allowed Animals.
  2. Prohibition of Blood.
  3. Prohibition of Mixing of Milk and Meat.

We will also focus on a few other special laws dealing with kosher production of dairy products. For more detailed information about A thru C beyond dairy, please see Regenstein and Regenstein, 1978.

Very briefly. (A) Allowed animals chew their cud and have split hooves, e.g., cattle, sheep, and goats. (B) Products derived from slaughtered animals that are allowed are not acceptable as kosher unless the animal is slaughtered according to kosher guidelines and has been inspected and treated according to the laws for meat production. (C) The prohibition of the mixing of milk and meat (“Thou shalt not slaughter the kid in the milk of its mother”) is a major prohibition (it appears three times in the first five books of the Bible) and leads to the definition of three categories of kosher products and equipment used to make kosher products. The three categories are meat, dairy, and pareve (neutral, neither meat nor dairy). The marking of these categories on food packages may also be valuable to non-Jews seeking this quick category screen. For example, vegetarian consumers may be grateful to know that a “dairy” product has no meat ingredients. Pareve products are both meat and dairy free.

However, non-kosher consumers must learn to relate these kosher markings to their own requirements; they may not line up perfectly. For example, meat derived from kosher slaughtered animals, if processed properly with respect to the kosher laws, may still be used to produce dairy products, e.g., cattle, sheep, or goat rennet. Traditionally, the amount of available kosher rennet was quite limited; until recently, most kosher cheese used various microbial enzymes. In the last few years, most cheese in the US uses biotechnology-derived chymosin, generally prepared microbially using a kosher fermenter with all kosher ingredients. As a result, the ingredients in most US industrial cheese today (as opposed to even a few years ago) is likely to have all “kosher” ingredients. So, why isn’t more cheese considered kosher?

Cholev Yisroel

We will now need to introduce three of those “special” laws related to the production of kosher food. Kosher milk can only come from kosher (“fit or proper”) animals. Many rabbis consider milk kosher as it leaves the farm. Some rabbis, however, require that the milk be “watched” from the time of milking and this milk is referred to as “cholev yisroel” or “Jewish milk.” Those who do not use this more stringent criterion do so based on two arguments: First, in the modern era, the US governmental agencies regulate milk closely so that adulteration of the milk by a non-kosher milk is highly unlikely. Second, the non-kosher milks are generally more valuable so there is no incentive to adulterate the kosher milks with these milks.

Gevinas Yisroel

A Jew must participate in the production of specifically selected foods. Most of the rabbis who are responsible for the normative mainstream kosher supervision of foods in the US require that a Jew participate in the making of most cheese (e.g., by adding the coagulant) other than the “fresh” cheeses like cottage cheese, farmer cheese, and cream cheese. This is a very specific requirement for cheese and is called in Hebrew “gevinas yisroel” or “Jewish cheese.” Thus, despite the fact that most cheese produced in the US uses kosher ingredients, the amount of US cheese that is kosher is quite limited.

The concept of a normative mainstream US kosher standard came about through surveys of kosher foods in the supermarket by a class on Kosher and Halal Food Regulations at Cornell University. Over 40% of the grocery products in the supermarket have a kosher certification and almost all of these reflect the same “normative” US standard. This de facto kosher standard in the US, which permits products to be interchanged between different supervisions, is represented by the major national supervision agencies, e.g., the OU, the OK, the Kof-K, and the Star-K, and recently the Half-Moon K. Many of the smaller kosher supervision agencies also use this same standard. There are numerous trademarked kosher symbols (over 400 at last count) that identify the kosher supervision agencies and, indirectly, their different (and sometimes controversial) standards of kosher supervision. Some are more lenient than the “normative” standard, while others are stricter. Please note that the letter “K” cannot be trademarked and any person/company can put a “K” on their product.

Bishul Yisroel

It is possible to obtain kosher by-products of cheese manufacture (e.g., whey) from cheese that is not compliant with gevinas yisroel but produced from approved animals using kosher ingredients and equipment. This can only be achieved if the whey does not fall under the requirements of “bishul yisroel” or “Jewish cooking.”


How does this work with whey? If ALL of the ingredients and equipment used in the plant are kosher and dairy – and the whey is separated from the cheese at or below 120F – then the whey can be kosher even if a Jew did not participate in the cheese making. If the whey is still with the cheese at 120F, the whey is considered “cooked” and acquires the status of cheese, which would require Jewish participation per “gevinas yisroel.” We recently learned that some of the Swiss cheese manufacturers have revised their production process so that the whey is separated below 120F and will qualify for kosher status. (Previously they worked (kneaded) the cheese in the hot whey and did the separation of the whey at about 125 to 127F so that this whey did not qualify for kosher status.) Any material separated from cheese above 120F -- such as the whey cream from Mozzarella cheese manufacture – would therefore not be considered kosher by this standard. And to the extent that this whey cream is used in making butter, the butter would not be kosher.

The use of whey cream from an otherwise kosher production does not “contaminate” the production equipment since all the ingredients are kosher. A butter plant would not have to clean its equipment between making a butter that has kosher whey cream that violates gevinas yisroel and a subsequent production that is compliant with the gevinas yisroel standard. However, a supervising rabbi would probably request that the kosher butter be made each day on cleaned equipment before the whey cream violating gevinas yisroel is used, if he permitted such a process (see below). If the whey cream was produced from a cheese that includes non-kosher ingredients, then the equipment is subject to the complete equipment kosherization process. The process for cold equipment (i.e., equipment used below 120F and therefore not involving cooking) is fairly straightforward (the normal cleaning prior to resuming kosher production is sufficient), while those for a hot process (i.e., cooking that occurs above 120F) requires the equipment to be idle for 24 hr after which the processing equipment must be flooded with boiling water.

In practical terms, because of the difficulty of monitoring the different types of whey cream coming into the butter plant and keeping them segregated throughout the processing, some rabbis may require that a plant either only use kosher whey cream or that it have a much higher level of inspection to assure that only the right type of whey cream is used for the kosher production. In most cases this will be cost prohibitive (which is why most cheese is not compliant with gevinas yisroel in the first place), so that in fact it is likely that only kosher whey cream would be permitted in a kosher butter plant.

Because of the changes in technology, production of all kosher butter therefore requires kosher supervision. Prior to the use of more sophisticated technology, butter was evaluated religiously rather like milk, for which minimal active kosher supervision was deemed necessary. This evolution reminds us that the day-to-day implementation of kosher supervision is constantly updated in our high tech world.

Until a few years ago, the various normative mainstream kosher certifying agencies used different temperatures for deciding when something was actually “cooked.” This led to a great deal of confusion when ingredients approved by one kosher supervision agency were then used to produce a final product under a different kosher supervision. It therefore became important to define a single designated temperature at which the laws related to “cooked product” would apply. It is interesting to note that the original required religious temperature test was that the kosher supervisor would feel the need to quickly remove his hand from the water because it was too. hot (Yes, “his hand”; there are no woman kosher supervisors in industrial kosher supervision.) Not surprisingly, the “approved” temperature would vary with the heat tolerance level of a given supervisor. It has been very helpful to define a single normative standard. However, the transition period (like any transition period) was awkward. The kosher supervision agencies often learn about significant changes in food processing technology rather by chance. Recently, there have been problems concerning butter and cheese as technology has changed and the kosher supervisor learns about the change during a regular inspection that is only performed a few times each year. It is anticipated that the major kosher agencies will establish more timely procedures for evaluating these products and for keeping up with processing changes over time, especially in plants NOT receiving regular kosher supervision such as was previously the case with butter plants.

Because of the complexities involved in combining multiple ingredients into retail products, it is important for ingredient companies to consider the use of normative mainstream standards if they choose to “go kosher.” This may require extra attention and possibly more stringent standards for ingredients for sale internationally since the standards of European and Israeli kosher supervision are different from those in the US.

Related Issues

Time between Dairy and Meat

Jewish tradition requires a separation between eating dairy and eating meat. The exact time varies depending on one’s country of origin but, in general, the wait after eating dairy before eating meat – from a single rinse of the mouth with water up to one hour – is much shorter than the wait to eat dairy after meat (three to six hours). Many kosher observant Jews will therefore eat dairy for breakfast and lunch, and then switch to meat for dinner. There is another requirement in this regard: If you eat a “hard” cheese, the wait after eating cheese is equal to the wait after eating meat. What is hard cheese? Two definitions exist: (1) a very dry cheese, particularly some of the Italian cheeses; or (2) cheeses that are aged for over six months. This is why many kosher cheeses are not aged as long as their non-kosher equivalents.


The tradition in the US used to be to mark pareve products with a specific mark indicating it was pareve, but not to specifically mark dairy products. In the past twenty years, the custom has changed and dairy products are marked, e.g., with a capital “D” next to the kosher symbol.

We believe it would be very helpful to clearly mark the “category” of all kosher products, i.e., with letters specifying meat, pareve, or dairy. Companies and kosher supervision agencies would be forced to review ingredients and processes a little more and consumers – both kosher-observant and others – can reap the greatest benefit of kosher purchases. Note, e.g., that the most frequent mislabeling “error” with kosher products occurs with respect to dairy and pareve designations, particularly leaving off the dairy designation – an error that can very dangerous for consumers with a dairy allergy.

A few of the supervising agencies permit the use of a “D.E.” symbol next to their kosher symbol, for “dairy equipment.” This means that the product has all pareve ingredients but was made on a dairy equipment line. The rules for using such products in a kosher home with a meat meal are complicated and some agencies have therefore decided not to allow their food companies to provide this information. However, this information could be very useful for non-kosher observant consumers.

A number of products, e.g., coffee whiteners, contain sodium caseinate but are labeled with the secular “Non-Dairy” designation. Sodium caseinate is a milk protein. There are legal reasons for the “Non-Dairy” label, so consumers are wise to revert to the ingredients list or the kosher symbol, if this issue is important to them.

In like fashion, we believe that dairy by-products should not be used to coat fruits and vegetables or any other product that does not have an ingredient label even if it is legally permissible to do so (e.g., the added material is treated as a processing aid). Such coatings are not generally labeled – again, a problem for kosher consumers and consumers with allergies. On the other hand, a requirement to label produce would force the products to be segregated into kosher and non-kosher sections of the (super)market counter!

To those consumers who depend on kosher to meet their dietary preferences, it is very important that things be done right. We thank everyone in the industry who undertakes the work involved in being kosher for your efforts to full this request. We hope this discussion is helpful and offer a few references for those wishing to understand kosher and halal (Muslim dietary laws) in somewhat greater detail.


References and Additional Readings

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