Is Pepsin from pigs being used for cheesemaking in the United States?

Question

A comment on this blog reads as follows:

Your information is INCORRECT. Following is an excerpt from a letter from KRAFT food.

"Thank you very much for asking if Kraft cheese products contain any animal derivatives. Our comments here apply only to products produced in the United States. Many cheese products produced in the United States do contain a coagulating enzyme derived from either beef or swine. The process of changing fluid milk into cheese consists of coagulating the milk by one of two commonly used methods, each resulting in cheese having distinct characteristics.

The most common method of coagulating milk is by the use of an enzyme preparation, rennet, which traditionally was made from the stomachs of veal calves. Since the consumption of calves for veal has not kept pace with the demand for rennet in the preparation of cheese, a distinct shortage of this enzyme has developed. Consequently, a few years ago it became a common practice to mix the rennet extract from calves' stomachs with a pepsin enzyme derived primarily from the stomachs of swine. These enzymes convert the fluid milk into a semi-solid mass as one of the steps in the manufacture of cheese. This mixture of calf rennet and pepsin extract is quite commonly and widely used within the United States."

The pdf file from FAO also mentions the usage of pepsin for cheese making:

Enzyme preparation Used in the preparation of fish meal and other protein hydrolysates, and the clotting of milk in cheese making in combination with one of the rennet.

The Halal Research Council also states that pepsin is generally used for making cheese:

Three enzymes used to make cheese are pepsin, lipase and rennet. These enzymes can be from animal, vegetable or microbial sources. Animal sources include pigs and cattle. Pepsin is derived from pigs, and is Haram.

Almost any source on cheesemaking that can be found online mentions rennet. Pig-based pepsin is not mentioned with the same frequency. This is why I am not sure about the reliability of my sources' claims.

Considering this, is it common practice to use pig based pepsin to make cheese?

I know that whey is also generated in the process of making cheese. Whey powder is a common ingredient in many chocolates. Is it likely that the whey powder in these chocolates was produced with the aid of pig-based pepsin?

Answer 1

As background, the Kraft letter in the OP has been truncated. The letter was from Ellen Schwarzbach of Kraft to a vegetarian group sometime prior to 1997 and continues after the portion quoted in the OP:

A more recent development in this area has been the use of enzymes derived from the growth of pure cultures of certain molds. These are termed microbial rennets. They are commonly used for the production of certain types of cheese and contain no animal products. Kraft Domestic Swiss Cheese (any Kraft Swiss not labeled "Imported" from a foreign country) is made with microbial rennet. Apart from Kraft Domestic Swiss Cheese, it is almost impossible for us to assure you that any hard cheese product which you might purchase from Kraft or any other American source is absolutely free of animal-derived enzymes.

The other method of coagulating milk is the result of the growth of pure cultures of bacteria in the milk and the development of lactic acid. These cheeses have distinctly different characteristics from those produced using the coagulating enzymes. Our cream cheese products under the PHILADELPHIA BRAND name (brick, whipped and soft varieties) and Kraft Neufchatel Cheese fall into this category. Kraft does not use coagulating enzymes in cheese of this type, but we cannot be sure what other manufacturers may use. Our process cheese and process cheese products are made by grinding and blending. With the aid of heat, cheese is made by either one of the two methods of coagulating mentioned above. Therefore, it is impossible for us to assure you that a given American-made process cheese product is free of animal-derived enzymes including pepsin and/or rennet.

According to Impact of New Milk Clotting Enzymes on Cheese Technology Journal of Dairy Science Vol. 58, No. 11, pages 1740-1750 (1975).

These trends triggered sharp escalation in veal rennet prices which in turn spurred the reintroduction of swine pepsin in 1960. Within 5 yr, swine pepsin and veal rennet-swine pepsin blends were utilized for production of the major proportion of cheese in the United States.

The more recent Fundamentals of Cheese Science (2000) says at page 132:

porcine pepsin has been withdrawn from most markets

Most recently, Detection of porcine pepsin in model cheese using polyclonal antibody-based ELISA Food Additives & Contaminants: Part A (2020) says:

The usage of porcine pepsin or other porcine derivatives in food products is a common practice in European, American and certain Asian countries although it creates issues in religious and personnel health concerns.

However, the Handbook of Halal Food Production (2018) says:

Until the mid-1980s, porcine pepsin was used in some cheese manufacture. Since the introduction of GM chymosin, the use of pepsin as a replacement for calf rennet has practically vanished.

A current ad for Native Porcine Pepsin says:

...used ... in the preparation of cheese

In conclusion, porcine pepsin was heavily used in the US cheese making in the 1965-1985 time period. Thereafter it was mostly replaced by microbial enzymes and then genetically engineered chymosin. However, porcine pepsin is still being sold for cheese making, so it is still possible that some US cheese is made using porcine pepsin.