Wheying the Kosher Possibilities

Food technology has made enormous strides since Miss Muffet sat down to her feast of curds and whey. Today whey has emerged as one of the most versatile food components with many new and exciting food applications. Typically, whey cream can be churned into butter or be converted into ricotta cheese. Whey can be dried into a powder and be used as a basic ingredient in cereals, baked beans, hot cocoa, and seasonings. Whey protein concentrate is a fundamental ingredient in infant formula and bakery products. Lactose, the milk sugar found in whey, is used as a flavor enhancer or a carrier in pharmaceuticals. In addition, whey is converted into alcohol and used in alcoholic beverages. Clearly the industry continues to discover whey’s versatility. Where does whey come from and what, if any, are the kashrus issues relating to whey in general, and cholov yisroel in particular? Furthermore, has the advent of more sophisticated food manufacturing simplified or complicated the life of the kosher consumer?

What is Whey? Whey is the basic by-product of cheese manufacturing. Although there are hundreds of types of cheese, all cheese has to undergo the same basic processes. First, the milk that is being converted into cheese is pasteurized so that any harmful bacteria will be killed. Depending upon the type of cheese produced, whole, part skim or skim, the milk may be separated to lower the milkfat content of the milk. Second, the pasteurized milk is pumped into a “cook vat” where a starter culture containing specific bacteria is added to the milk. The bacteria in the starter culture forms acids in the milk and lowers the pH of the milk to a critical acidity level. It is the culture which gives different cheeses their special characteristics. Every variety of cheese needs to be cooked at a specific temperature so that the culture can work. If the specific temperature is not maintained, the bacteria in the starter culture fail to multiply and the cheese process could not continue. Depending upon the culture, some cheeses are cooked at low temperatures, within 86 F – 96 F range. Other cheeses are cooked at much higher temperatures, between 120 F – 130 F. After the culture is thoroughly blended, rennet, a substance containing enzymes, is added to the milk. It is the rennet that allows the milk to coagulate and to set. The coagulated milk is formed into a smooth, custard like solid which is called the curd. Finally, the curd is ready to be cut, which means that the cheese maker breaks up the curd, separating a rich cloudy liquid from the solid pebble-like curds. This liquid cloudy water, is known as whey.

Liquid whey is rich in protein, lactose and minerals. Whey’s functionality has only been realized in the past 25 years. But general use of nisyovay d’chalvah, whey, has been known for thousands of years and is mentioned in the Talmud.

I. Producing Whey
Kosher Cheesemaking: In earlier generations, in order to make kosher cheese it was necessary to use rennet from an animal that was slaughtered and kashered properly. The halacha prohibits cheese that was coagulated with non-kosher rennet or non-kosher enzymes. Natural rennet is derived from the lining of a calf’s stomach. Today microbial rennet is widely used in cheese productions. This rennet is produced by growing the protein on microorganisms. These rennets are readily available with reliable kosher certification.

In kosher cheese production, even if the rennet and starter culture are kosher, our Rabbis have decreed that in order for the cheese to be kosher, a Yehudi, a person who adheres to the laws of kashrus and is personally observant, must put the starter culture, rennet and/or other coagulation media into the milk. If not, the cheese would be forbidden. The Rabbinically non permitted cheese is known as gevinas akum.

Kosher cheese can only be made from milk of behaimos tehoros, kosher species. Based on this requirement, many Poskim, authorities of Jewish law, maintain that if the milk that is being used for cheese making has been designated to make cheese, this milk is not subject to cholov akum (i.e., milk that was not supervised by a mashgiach, a Yehudi supervisor) disqualification and remains cholov stam. This means that non supervised milk can be used to make kosher cheese.

Kosher Whey Making:
Is whey subjected to the same halachic restrictions as kosher cheese? Not entirely. As previously mentioned, the milk used for the cheesemaking is not subject to cholov akum disqualification. Furthermore, if the cheesemaking ingredients (the starter culture and the rennet) are kosher and the cheese has been “cooked” below yad soledes, 120 F, even if a mashgiach was not present to add the coagulating media, the whey would be permitted. This is because the whey, a kosher milk by-product, has never absorbed any disqualifying taam, taste, from the cheese curd.

Wayward Whey:
With the increased demand for liquid whey, the dairy industry has achieved alternative methods of recapturing whey. Some of these methods may present serious halachic issues. Today whey is retrieved also from Swiss cheese and Mozzarella cheese productions. The milk curd in Swiss cheese productions is cooked in temperatures exceeding yad soledes, 120 F. That means that the whey has absorbed the taam, taste, of the non kosher Swiss cheese.

In order to give elasticity to mozzarella cheese, the cheese curd undergoes a second process. The cheese curds are cooked and stretched in a hot water stretcher (140 F-160 F). This gives mozzarella its elasticity. Although smaller mozzarella cheese companies discard the cook water, larger companies recognizing whey’s value have started to retrieve the whey out of the mozzarella cook water. In these cases, where whey is retrieved from hot curd or hot cheese cook water productions, the whey has absorbed the taste from non-kosher cheese and would possibly be subject to the restrictions of gevinas akum.

Interestingly, other Rabbinic authorities postulate a more liberal position regarding whey produced from cheese “cooked” at a temperature that had exceeded yad soledes, 120 F. They maintain that in the U.S., cheese is produced using all kosher ingredients. The government maintains strict restrictions and imposes stiff penalties if manufacturers deviate from using cows’ milk. The rennet used is largely microbial and even if non-kosher rennet was used, it has undergone so many processes that it is no longer fit for human consumption, eino ra’uy l’achilas kelev. Since the milk and other ingredients were never prohibited, the whey, a milk by-product that was separated from the cheese, has absorbed taste from kosher ingredients and would be permissible. The gezaira d’rabonon for gevinas akum only addresses the cheese curds.

II. Whey Products
Ricotta Cheese: Ricotta cheese, unlike traditional cheese, is made by cooking liquid whey at very high temperatures with live steam. An acid, usually acetic acid or vinegar, is added, resulting in a curded ricotta cheese. Typically, liquid whey was used to produce ricotta cheese. Ricotta cheese can be made with different ingredients, depending on the tastes of the consumer. Some companies substitute milk instead of whey to make the ricotta.

Since ricotta is not made in a conventional cheese method, should ricotta be subject to the laws of gevinas yisroel? Is a mashgiach required to add the coagulating media? Does the milk in ricotta cheese need to be cholov yisroel? Those authorities that consider ricotta a regular cheese would permit ricotta cheese made from non-cholov yisroel milk because the milk was designated for cheesemaking and thereby did not obtain the status of cholov akum. However, a mashgiach would have to add the coagulating media. If one follows the opinion that ricotta is a soft cheese, a mashgiach need not add the coagulating media. However, the milk used for the ricotta cheese would be subject to cholov yisroel restrictions.

Whey cream butter: When dairies separate whole milk, it is separated into two products: skim milk and cream. Butter is made by churning the separated cream into butter.

The Shulchan Aruch permits the use of natural, pure butter produced from non supervised milk for cholov yisroel consumption. The halacha maintains that the Rabbinic decree of cholov akum did not include butter. Whey cream can also be churned into butter. Like whole milk, whole liquid whey can be separated into sweet whey and whey cream. The whey cream can be added to regular milk cream and be churned into butter or the whey alone can be churned into whey cream butter. Just like kosher whey, kosher whey cream butter would be acceptable.

However, if the whey cream was separated from non-kosher whey and would subsequently be churned into butter, this butter could present serious kashrus problems. Is this a wide spread concern and do all kosher consumers have to purchase butter with reliable kosher certification?

In the U.S. the sign signifying butter’s highest quality is Grade AA. In the past it has been customary to purchase any butter, even with no kosher certification, bearing the Grade AA shield. It has been an age-old assumption that grade AA butter has been churned from milk cream exclusively.

However, the truth behind the AA shield is that the seal represents a quality taste standard rather than an ingredient standard. That means that if the whey cream has the same flavor, body and color of milk cream, it could potentially qualify for grade AA.

In truth, it is highly unlikely that whey cream would qualify for grade AA butter. It is nearly impossible to achieve AA quality from whey cream. Typically whey cream qualifies for grade B butter. Furthermore, most butter churning facilities churn milk cream exclusively. It is rarer yet to find Swiss cheese whey or mozzarella cook water whey being churned into butter, let alone AA butter. As one of the largest grade AA butter producers told the Star-K, “We haven’t used whey cream for 30 years and we don’t intend to use it now.”

Another ingredient commonly used in sweet unsalted butter is diacetyl. Diacetyl is used as a flavor enhancer and as a preservative. It can be naturally derived from milk or can be produced synthetically.

Can a cholov yisroel adherent who uses non-cholov yisroel butter use regular non-cholov yisroel butter that lists natural flavors in the ingredients? There are many reasons to allow its use. Diacetyl may not necessarily be used in the butter. Furthermore, the diacetyl may be synthetic and would be pareve. Even if a dairy diacetyl is used, it is used in such small amounts it is batul, nullified, in the butter. Therefore, for these reasons, butter listing natural flavors may be used. Each individual should clarify this issue with their Rabbi or halachic authority.

III. Powdered Whey
Food processors have found many uses for whey components as well. Through a water filtration process known as osmosis, whole liquid whey can be separated into its basic components, i.e., whey protein and lactose. Today, whey protein and lactose are used for a host of food applications. However, it is impractical to use them in their liquid form. When used as food ingredients, they are dried into a powder. A popular technology used to dry these ingredients is known as spray drying.

Spray drying is a method used to dry a whole array of products. They include: milk, whey, flavors and colors, as well as cheese and meat. Kosher spray drying has raised numerous issues that have to be addressed. Does the company do their own spray drying? Many do not since spray dryers can be quite costly. It is more cost-effective for a company to request a company specializing in spray drying to custom spray dry their product. This is known as contract spray drying.

If a kosher product is custom spray dried, it is imperative to know what else is being spray dried on that same machine. Moreover, if a spray drier needs kosherization, how do you kasher a spray dryer? Can you kasher a spray dryer? If the spray drier can be kashered through hagola, can a four story spray dryer be cleaned sufficiently well for kashering?

If a spray dryer is being kashered for cholov yisroel dairy productions, another issue must be addressed. Cholov yisroel powdered milk is typically dried by companies that spray dry regular milk powder. It is common practice for spray-drying milk dairies to clean their equipment with the abundant amount of water retrieved from the spray dried milk process. In the trade, this water is known as “cow water.” Cow water looks like 100% clear water but is milchig and may be considered cholov stam! Using cow water for cleaning or heating a boiler would disqualify a spray dryer for cholov yisroel spray drying. When preparing for a run of cholov yisroel dry milk powder massive cleanups with regular water take place before kosherization.

Is cholov yisroel spray dried whey available? Unfortunately, commercial spray drying requires an enormous amount of liquid product to make a production. Due to the fact that such a volume of cholov yisroel liquid whey is not produced, cholov yisroel powdered whey is not readily available. This is the reason why you will rarely find foods that contain whey or casseinate, a dairy protein, certified as cholov yisroel.

Can regular kosher certified (non-cholov yisroel) powdered whey be used by a cholov yisroel adherent? A good case can be made for the use of regular kosher powdered whey, even by cholov yisroel adherents.

As previously mentioned, liquid whey can be certified kosher if the following criteria are met:

  • the milk has to be designated for cheesemaking;
  • the coagulating ingredients have to be kosher; and
  • the cheese curd cannot be heated above 120 F.

Furthermore, powdered whey is viewed even more favorably due to the fact that the Rabbinic decree of gevinas akum did not address a powdered product. However, it is the Star-K policy to only use cholov yisroel products, including powdered whey.

Can a cholov yisroel adherent be lenient with powdered milk? According to some Rabbinic authorities, powdered milk produced in the U.S. would also have a similar lenient halachic ruling for the following reasons:


  • By law, milk spray dried in the United States (or in countries having the same strict government milk regulation) must come from cow’s milk or from milk of a behaima tehora.
  • The Rabbinic decree of cholov akum never addressed powdered products.

Hence, some Poskim maintain that products made with non-cholov yisroel powdered milk can be enjoyed by the cholov yisroel consumer.

Today, most people who are careful about cholov yisroel do not rely on these lenient rulings and only use cholov yisroel powdered milk products. The Star-K does not certify products which use regular butter whey or milk unless they are made from cholov yisroel milk. We expect that with the increased interest in cholov yisroel, more and more cholov yisroel dairy products will be available for the kosher consumer to enjoy.