Are GMOs Used to Make Organic Cheese?

Posted on June 7, 2013


Recently, I’ve been part of some discussions relating to the use of enzymes derived from genetically modified organisms (GMOs) in organic cheese production. The concern, or the assumption, is that they are employing the same GMO-derived chymosin (known less precisely as “rennet”) as about 70% of the cheese on the market today. That didn’t sound quite right to me, so rather than accept rumour and speculation, I decided to do a little research, looking at organic certification regimes from around the world. Here are the results of my work:

United Kingdom

The Soil Association is the United Kingdom’s largest organic certification body, verifying the organic status of over 70% of the organic products sold there. Their website explains: “All organic products must not use GM organisms or their derivatives. This includes enzymes which must be from non GM organisms. To ensure that this is the case every cheese manufacturer must submit a GM declaration from their ‘rennet’ supplier that the material is not derived from a GM organism.”

That’s pretty clear: No GMOs used to make organic cheese in the UK.

United States

An excellent background document on the history of cheese enzymes and the development of chymosin derived from genetically modified organisms can be found on the Vegetarian Resource Group Blog (because probably the only people who care more about the provenance of their cheese enzymes than organic consumers are vegetarians!). They report on extensive communications with enzyme manufacturers, including the world-wide company Chr. Hansen. On the topic of organic cheese, they state quite clearly that GMO-derived enzymes cannot be used in USDA Organic cheese. Chr. Hansen’s website offers this explanation (emphasis is theirs) before listing several non-GMO alternative that are permitted for organic use:

Organic products are products which exclude the use of inputs such as pesticides, chemical fertilizers and food additives. Although organic certification varies according to jurisdiction, organic products produced with the aid of GM technology may not be certified Organic. Thus, products such as Fermentation-Produced Chymosin and YieldMAX®may not be used in organic end-products.

A 2011 USDA AMS Technical Evaluation Report on Enzymes in organic products clearly states:

Genetically modified rennet (fermentation produced chymosin) is prohibited for use in organic agriculture 355 under 7 CFR 205.105(e) and 7 CFR 205.301(f).

The same report goes on to provide an international perspective by stating (emphasis is mine):

The Codex Alimentarius Commission organic food guidelines allow preparations of micro-organisms and enzymes, specifically, “any preparations of micro-organisms and enzymes normally used in food processing, with the exception of micro-organisms genetically engineered/modified or enzymes derived from genetic engineering” (Codex Alimentarius Commission, 1999; USDA, 2000).

The most recent edition of the International Federation of Organic Agriculture Movements (IFOAM) Basic Standards considers enzymes acceptable for use in organic food processing provided they are based on the established Procedure to Evaluate Additives and Processing Aids for Organic Food Products (IFOAM, 2005; USDA, 2003). These standards are generally parallel to the OFPA criteria. [i.e. no GMOs or derivatives permitted]

Again, quite clear: No GMOs used to make organic cheese in the US (and probably the rest of the world!)


Canada’s organic regime features a Permitted Substances List (PSL) which includes all of the products that are permitted for use in organic agriculture in Canada. Section 6.4 of this list includes Dairy Cultures, with the specific annotation:

May not be products of recombinant DNA technology.

A little further down in the same section it also lists Micro-organisms, with an even more detailed explanation (emphasis is mine):

Including any preparations of micro-organisms normally used in product processing,
excepting micro-organisms from genetic engineering or enzymes derived from
genetic engineering, with no added chemosynthetic substance.

Just to be extra sure, I contacted Pro-Cert Organic Systems, Canada’s largest certification body, and asked two questions: “Can organic cheesemakers use rennet/chymosin derived from genetically modified organisms, or is it prohibited as per 1.4.1a” [the section of the Canadian Organic Standard the prohibits GMOs] and, “Does Pro-Cert verify the non-GMO status of enzymes used in organic cheese production? This is the response I received (quoted with their permission):

GMO enzymes would not be permitted. This would be covered under 1.4.1.a and in the PSL 6.4.

Pro-Cert does verify the GMO status of enzymes and the other requirements of enzymes in PSL 6.4

For the third time: No GMOs used to make organic cheese in Canada!

What’s Used in Organic Cheese

Since first posting this, a number of people have assumed that because organic cheese doesn’t use GMO enzymes, it must use calf rennet. There is, however, the third option of microbial rennet produced using a few different organisms first discovered in soil. “Hannilase” appears to be one of the most popular of these products. It’s very common to see references to this type of microbial rennet note that the resulting cheese often has a bitter aftertaste. But if appears that a purification process can eliminate the enzymes that cause this secondary reaction. Based on my experiences eating organic cheeses made using “vegetarian rennet” the end results can be pretty delicious!


Everyone is entitled to their own opinion on the importance or relevance of the use of enzymes derived from GMOs in cheese production. But one fact is very clear: these GMO-derived enzymes are NOT used in organic cheese.


Posted in: Food, Organic