Dairy Industry Training Webinar

On Friday October 16th the OU presented the first of a two-part webinar (Internet seminar) on dairy hashgacha. The second session took place one week later on Friday, October 23. Rabbi Yaakov Mendelson, Senior Dairy RC, moderated the sessions and presented e-mail questions sent in advance and on-the-spot by RFRs; Rabbi Avrohom Gordimer and Rabbi Avrohom Juravel responded verbally and live to the questions.

RFRs were sent a detailed dairy kashrus information packet for use during and after the webinar.

There was very positive feedback from Senior Management and RFRs on the success of this webinar in terms of ongoing RFR education and training. We look forward to more such excellent webinars in other industries as well.

The topics that were covered in the webinar were

  1. Fluid milk
  2. Powdered milk
  3. Fresh cream
  4. Whey cream
  5. Butter
  6. Hard cheese
  7. Soft cheese
  8. Whey
  9. Sour cream
  10. Yogurt
  11. Ice cream

In the following RFR’s were given guidance concerning each topic as to what Kashrus issues they should be aware of as they do their inspections.

Webinar Dairy Issues:

By Rabbi Avrohom Juravel and Rabbi Avrohom Gordimer

Fluid Milk:

When going to a fluid milk plant, it is important to ascertain what else is processed there. While fluid milk is intrinsically kosher, it goes through various processes that could have kashrus problems. These include, but are not limited to: separators, pasteurizers, and storage tanks. Chocolate milk, eggnog, and even chicken soup have been found to be processed on the same equipment as fluid milk. Due diligence is not only a virtue, it is a requirement. Note: In ultra-high pasteurization (UHT) dairies, which make long shelf-life product in boxes or pouches, the likelihood of shared equipment issues is very great.

Powdered Milk:

This product starts off as fluid milk, goes through a separator where the cream (fatty part of milk) is removed. From there it goes through a series of evaporators, mixing/holding tanks, and from there to a spray dryer. It is imperative to keep track what the equipment is used for. It can easily be used to dry other materials besides milk, which may not be kosher.

Fresh Cream:

Fresh cream (also called “sweet cream”) is taken from the milk by putting the whole milk into a separator, which is really a centrifuge. Cream is lighter than milk, so it floats to the top when put through a centrifuge. The optimum temperature for separating the milk from the cream is about 140F. Therefore, the milk is put through a heat exchanger before it gets separated. An RFR must have a thorough knowledge of the workings of the plant and keep track of what else is going through the heat exchanger that heats the cream. He must also keep track of where and into which tanks the fresh cream is going, and ascertain that the tanks are not used for anything non-kosher.

Whey Cream:

Whey is a by-product of cheese making. There are plants where both the cheese and the whey are non-kosher. Just like milk has a cream content, whey also has a cream content. (As with milk, whey’s cream is its fat component.) By putting whey through a separator just like milk, you will end up with whey cream. Most factories keep the whey cream and the fresh cream separate. These are two very different commodities with very different values. However, in a plant where the whey is not kosher, one must keep track of where the whey cream is separated, stored, heated, etc. to make sure the kashrus of the fresh cream is not compromised. For this very reason, we do not accept fresh cream from any plant that also deals or produces whey cream, unless it is properly kosher-certified.


Butter is made by taking cream and churning it. The churning process smashes the fat molecule and inverts it, thus yielding a very smooth, uniform, and almost solid product. The water that does not go along with the butter is called classic buttermilk (not to be confused with cultured buttermilk). Butter can be made both from fresh cream and from whey cream (See Chasam Sofer Yoreh Deah s. 79). Even USDA grade AA butter can contain significant amounts of whey cream. The certification program at a butter plant revolves around checking the cream sources. The cream will be coming in bulk by tanker truck. Each load has paperwork as to where it was picked up and produced. The RFR must meticulously check ALL the cream deliveries. He must also check what other ingredients they add to the butter against the schedule A.

Hard Cheese:

This product is made by starting with milk (whole, skim, powdered, or combinations of the above), adding cream and/or skim milk when called for. All these are put into a cheese vat, cultures are added, and when the pH changes, rennet is added. The vat is left alone for anywhere from 20 minutes to 3 hours, the cheese is cut, and the whey is drained out. The OU is machmir like the Poskim who say that the cultures and the rennet must be put into the vat by a YID. After the whey is drained out, the cheese is pumped into molds and sometimes it goes into brine. For kosher cheese productions, the brine must be fresh brine, not having been used previously for any non-kosher cheese, and the brine tank must be new and kosher-dedicated or kashered or lined in accordance with OU policy .

Soft Cheese:

Milk, non-fat dry milk (“NFDM”), whey and cream are put into a vat. Various acid cultures, possibly other acids (such as vinegar) and stabilizers are put in, and in these temperature-controlled vats the mixture is allowed to separate. The whey is drained off, and we are left with soft cheese. The cultures and the temperatures will determine what type of cheese it will become. Since there is no rennet, what is making the cheese here is the acid. Therefore this is known as acid- set cheese. The whey, which is a by-product of this cheese production, is always going to be an acid whey. The RFR must check the schedule A very carefully to see that the cultures match schedule A. He must also be aware that since acid set cheese is very often made at high temperatures, the equipment used in this type of cheese making must be dedicated for kosher use or be kashered before a production.


Whenever there is cheese production (or casein production), there will be whey. Whey is the uncoagulated part of the milk that is the byproduct of cheese production. When the whey is coming from hard cheese, the RFR must check that the temperature of the cheese vat does not reach or exceed 120 F. If the temperature reaches or exceeds that, we have whey cooking with GEVINAS AKUM. He must also see that all the rennet and cultures are kosher. If they are using animal-derived rennet to set the cheese, then the whey is not acceptable to the OU. Usually, the whey comes off the cheese vat after the cheese coagulates. In some instances, the coagulated cheese is washed with hot water in order to get it to expel more whey. This process is known as scalding the cheese. The whey that comes out of this process is not considered kosher.

Mozzarella cheese goes through an additional process called stretching. This is accomplished by immersing the cheese in a very hot bath which will soften it, and then through a mixer/molder which stretches it. The water from the hot bath (“cooker” in industrial terms) is generally between 150 F-175 F. Sometimes, this water is returned to the rest of the whey. When this happens, not only is the whey non-kosher, but the whey cream which comes off the whey will also become non-kosher.

It cannot be emphasized enough that the RFR at a whey plant must be totally familiar with every part of the process, and evaluate whether there are any pieces of machinery (separator, pasteurizer, heat exchangers, evaporators, tanks, etc.) that can become kosher-contaminated along the way. Please remember that we are certifying the whey which is the by-product of non-kosher cheese (GEVINAS AKUM). Total segregation of kosher and non-kosher is imperative.

Sour Cream:

Cream, milk, cultures, stabilizers, and emulsifiers are standard ingredients in sour cream. Cream, not like its closely-related cousin butter, is a liquid, not a solid. In order to solidify cream, cultures are put in which will change the taste and have some effect on the texture. This is still not enough to solidify it. Starch, stabilizers, and emulsifiers will accomplish this task. The problem we encounter is that a lot of sour cream stabilizers have non-kosher GELATIN in them. This is especially relevant in light sour creams. The less the cream content, the more the gelatin. The stabilizer itself can have high amounts of gelatin, even though the final sour cream product has only a small amount. We will not certify the product even with a minimal amount of gelatin in it.

The gelatin problem rears its ugly head when a plants adds gelatin or stabilizer that contains gelatin to a small amount of cream in a liquefier, creating a “pre-mix” A liquefier is a very-high speed mixer which will mix and blend the gelatin into a small amount of cream, and then send it to the big vat of sour cream mix. This is done with other stabilizers also, even the kosher ones. Oftentimes, the liquefier is heated, rendering it non-kosher because of the large amount of gelatin in the pre-mix. Although the total amount of gelatin in the final product is botel, in the liquefier it is not botul. When the same liquefier is used for a kosher stabilizer, it can be rendered non-kosher because the liquefier was not kashered. Similarly, if the liquefier processed a pre-mix which contained gelatin that was not botel therein, and that pre-mix gets mixed into the rest of the product (which it surely does – that is the whole idea of a pre-mix), the rest of the product will become non-kosher, as we view the entire pre-mix as non-kosher (ChaNaN), and the pasteurization equipment will thus also need to be kashered. It is necessary to verify that a pre-mix which contains gelatin is not made, or that the entire line is kashered if such a pre-mix is made.

Again, unless the RFR understands the complete workings of the plant, he may check the formula of the non-kosher gelatin and decide it is always botul, and he will ignore the fact that the liquefier (and subsequently the pasteurizer) is TRAIF!


Yogurt starts with milk (fresh or NFDM) and cultures. The milk is inoculated with the culture, it is kept in a thermostatically-controlled holding tank, and after many hours, the whole thing turns into yogurt. After we have yogurt, flavors, sweeteners, starch, fruit fillings, and stabilizers are added. The best way to keep the fruit in suspension is by adding a stabilizer called gelatin. An RFR must carefully monitor the stabilizer systems they use and ascertain which products contain gelatin and which do not. He should also be checking all the other ingredients (stabilizers, fruit preparations, flavors, cultures, etc.) and compare them to the labels of the finished products. The same exact issue of pre-mixes with gelatin that was detailed in the case of sour cream applies equally to yogurt plants, where it is quite common. RFR beware!

Ice Cream:

Cream (fresh cream or whey cream), milk powder, sweeteners, stabilizers, emulsifiers, and flavors make up ice cream. When a product like ice cream freezes, small ice crystals form. This is not what the customer wants to taste. He wants the smooth mouthfeel of a creamy product. We all know that oil and water do not mix very well. In order to get the components of ice cream to mix, stabilizers and emulsifiers are used. When the right ones are used in the right proportions, a smooth creamy product will be the result, even when frozen, and it will not form minute ice crystals in the product. The RFR must be very vigilant in checking the stabilizer systems.

Ice cream comes in many flavors and varieties. Some may be kosher, while some may not be kosher. Rocky road is usually not kosher because of the non-kosher marshmallows it contains. Often, other ice cream varieties contain non-kosher marshmallows and are called by different names (e.g. Heavenly Hash, etc.). While the flavors are usually put into the ice cream mix after the ice cream is made, rework and remelt is an issue that must be very closely monitored.

OU Kosher Staff