National Organic Standards Board 

Crops Committee 

Corn Steep Liquor 

Proposed Synthetic/Nonsynthetic Determination 

March 9, 2011

Introduction 

Corn Steep Liquor (CSL) is a byproduct of the corn wet milling process, as well as several 

other commercial corn processing industries. CSL material from the wet milling process has 

been considered non-synthetic in the past by stakeholders including accredited certifying 

agents (ACAs) and the Organic Materials Review Institute (OMRI). It has been used for many 

years as a nonsynthetic input mostly in liquid fertilizer formulations for organic crop production. 

CSL was recently reevaluated by OMRI using the NOSB’s 2005 clarifications regarding the 

classification of synthetic and nonsynthetic substances and concluded that CSL should be 

classified as synthetic based on the use of sulfur dioxide during processing. A new clarification 

was passed by the NOSB in November of 2009 that is the clarification that the Crops 

Committee (CC) used in their determination. 

 

Background 

In an action memorandum dated April 23, 2010, the National Organic Program (NOP) 

requested that the National Organic Standards Board (NOSB) review corn steep liquor (CLS) 

concerning its classification as synthetic or nonsynthetic as an input for crop production for the 

Fall 2010 NOSB meeting. In considering this request, the CC asked the following questions of 

S&T: 

1. Does the change to the molecule occur to any significant degree under the conditions 

typically found (temp, pH, form of sulfur present, etc.) in the manufacture of this 

product? What is the classification of this chemical change if there is a change? For 

example is it breaking the bond so the protein goes from insoluble to soluble? Is the 

physical orientation changed versus the chemical structure in terms of molecules – the 

name of the chemical formula is identical but the rotation is changed? 

2. If so (and only if so), does the physical re-orientation of the atoms in the bond constitute 

a chemical change, or merely a structural change with no change in chemistry? 

3. What other materials made from this process that are currently on the National List 

would be effected if we determine that this process causes a chemical change sufficient 

to be designated synthetic? And in addition to that, what products that are currently on 

the list that use these materials would be affected? (i.e. liquid fertilizers that use Corn 

Steep Liquor and other materials like starch that may be used in fertilizer or pesticide 

formulations) 

4. Can CSL be made without the use of prohibited substances? Are there other 

materials that are more benign that can be used to make CSL? 
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5. Are there other permitted materials that could be used instead of CSL in its current use? 

The Technical Review received in February of 2010, while not answering these questions 

directly, was deemed adequate by the Crops Committee to go forward with discussions of 

synthetic/non-synthetic determination for CSL. This determination was discussed over the 

course of a number of CC weekly meetings. 

Relevant areas in the Rule 

In crop production, nonsynthetic substances are allowed unless listed on the NL §205.602, 

while synthetic substances are prohibited unless listed on the NL §205.601. 

OFPA defines Synthetic as “a substance that is formulated or manufactured by a chemical 

process or by a process that chemically changes a substance extracted from a naturally 

occurring plant, animal, or mineral sources, except that such term shall not apply to 

substances created by naturally occurring biological processes” (§2103 (21)) and 

Nonsynthetic (natural) is defined as “a substance that is derived from mineral, plant, or 

animal matter and does not undergo a synthetic process as defined in section 6502 (21) of the 

Act (7 U.S.C. 6502(21)). For the purposes of this part, nonsynthetic is used as a synonym for 

natural as the term used in the Act” (§205.2 Terms defined). 

Chemical change is defined by the November 2009 recommendation as “an occurrence 

whereby the identity of a substance is modified, such that the resulting substance possesses a 

different distinct identity (see related definition of “substance). As discussed by the Materials 

Working Group (MWG) in their recommendation, chemical change is “an event in which one 

substance becomes one or more difference substances.” Chemical change would not 

necessarily include processes like ion-exchange or pH adjustment if the final material was not 

a different substance from the initial substance. For clarity, a definition of substance is included 

in the recommendation as well: Substance An element, molecular species, or chemical 

compound that possesses a distinct identity (e.g., having a separate Chemical Abstract 

Service (CAS) number, Codex International Numbering System (INS) number, or FDA or other 

agency standard of identity). 

Discussion 

The Crops Committee determined that the status of Corn Steep Liquor (CSL) should remain 

non-synthetic. Last fall, the Crops Committee voted to classify CSL as synthetic based 

primarily on findings in the Technical Review (TR) (29-30), which states that, “The major 

objectives for corn steeping are to induce chemical and physical changes in the kernel by 

leaching the soluble components from the corn. “ It goes on to say that “sulfur dioxide is added 

at rates of 0.1 to 0.2 percent and is used to cleave disulfide linkages, resulting in the 

degradation of the corn protein that encapsulates the starch granules. “ (TR 99-102) The 

cleavage process breaks chemical bonds, thus releasing amino acids from the protein matrix 

into the CSL liquid The committee was also concerned that the term “corn steep liquor” may be 

applied to products of different processes, and that some of these products may have 

unknown characteristics. This recommendation was forwarded to the USDA NOP and posted 
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for public comment at the Fall 2010 NOSB meeting; however, the CC at that time also 

withdrew that recommendation from consideration by the full Board immediately prior to the 

Fall 2010 meeting. Regardless, the Board received 8 public comments in writing and 10 

comments in person for and at the Fall 2010 meeting. While all the public comments were 

given full attention and consideration one commenter, Dragan Macura from Agro-Thrive, gave 

an excellent presentation to the board on the process of making corn steep liquor via the 

traditional countercurrent wet milling process. Throughout the detailed discussion it became 

clear that the sulfur dioxide was added at the end of the process to stop the fermentation 

process (a biological process) and prevent putrefaction. 

Since the Fall 2010 NOSB meeting and a full board discussion of the information and the input 

from the general public, the CC has voted on January 24, 2011 to classify CSL as nonsynthetic when created as a food processing waste from the traditional countercurrent corn wet 

milling process, based on a through review of all the information, documents, and public 

comments presented to the committee. The majority of the CC determined that the sulfur 

dioxide’s utility in this process is in holding back a biological process (fermentation) and to 

prevent putrefaction and does not change the identity of CSL. The consensus of the majority is 

that this material when created in the manner described should continue to be considered 

nonsynthetic and appropriate for use in organic crop production. The majority considered that 

agricultural by products, food waste and products from food waste processing should not be 

considered as a synthetic ingredient for the purposes of organic crop production or the making 

of compost. 

Corn starch has previously been determined to be nonsynthetic and agricultural by NOSB, and 

is made using the exact same steeping process as CSL. It is common usage in the organic 

food system as are other derivatives of this process. In the 1995 TAP Review for native 

cornstarch, reviewer Richard Theuer stated that “sulfur dioxide is used as a ‘temporary’ 

preservative to avoid purification of soaked corn. Later, fermentation inhibits putrefactive 

organisms.” Dr. Theuer’s recommendation was that cornstarch be classified as nonsynthetic. 

That same year, the NOSB determined that the SO2 used in corn starch production was a 

processing aid. 

CSL has a long history of safe use as an added source of nutrition in animal feed, in 

fermentation processes, and in antibiotic production. It is not a significant source of water or 

air pollution. Due to the fact that CSL is composed of proteins, amino acids, carbohydrates, 

organic acids (such as lactic acid), vitamins, minerals and water, no environmental 

contamination would be expected. These components are all readily utilized by animals and 

microorganisms. In fact, CSL is a nutrient rich product that has been safely used as a 

component in livestock feed, fertilizers, and soil conditioners for many years. CSL and other 

nonsynthetic agricultural by products have historically provided and continue to provide a 

valuable source of nutrients for both soil microbial communities and organic crops. Historically, 

synthetic processing aids used in food have not been determined to render agricultural 

products synthetic; precedents are numerous and well established, with the end result 

providing organic producers with much needed agricultural by-products for use in composting 

and as soil amendments, and fertilizers. 
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Furthermore, the proposal that CSL should be considered to be non-synthetic is attributed to 

the fact that the SO2 action occurs in the endosperm protein matrix of the corn kernel, not in 

the steep water. There is compelling evidence that the proteins that the SO2 may alter are 

insoluble, thus are not a part of the CSL. General analysis of corn steep liquor reports the SO2 

in CSL from 0.0009 – 0.015 (Liggett and Koffler, 1948). For use in organic crop production, 

the CSL is typically blended with other approved materials or used as a compost feedstock, 

which would further reduce the already insignificant levels of SO2 to be non-detectable. 

The action of the SO2 in the countercurrent (traditional) corn wet milling process does not 

render CSL synthetic; the SO2 provides a buffering action to allow lactic acid fermentation to 

dominate over putrefaction. There is no evidence indicating that that the identity—that which 

makes the subject in question unique in its behavior, character, or function—of corn steep 

liquor as used is any different with or without SO2 as a processing aid. The behavior, character 

and function of the two are indistinguishable and on that basis alone, CSL remains nonsynthetic. 

Recommendation 

The Crops Committee recommends that Corn Steep Liquor produced via the traditional 

countercurrent corn wet milling process be considered as non-synthetic and allowed for use in 

organic crop production. 

Committee Vote 

Motion: Consider CSL to be non-synthetic when produced via the traditional countercurrent 

corn wet milling process only. 

Motion: Jeff Moyer Second: Tina Ellor 

Yes: 4 No: 3 Abstain: 0 Absent: 0

 
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Minority Opinion 

The issue we are considering, in determining whether CSL is synthetic or non-synthetic, is a 

foundational issue in the determination of allowable inputs in organic production. The 

determination itself of whether an input is synthetic does not always determine whether that 

input is allowable in organic. It simply ensures that the NOSB carries out its responsibility to 

review and evaluate whether the use of that synthetic material meets the law’s standards of 

sustainability. Organic integrity is built on the principle of objective review and transparency to 

ensure that the organic consumers’ expectations are being met and that there is a level playing 

field for all those engaged in organic production. 

The minority’s position that CSL must be defined as a synthetic product is actually very 

straightforward and follows the policies and history of longstanding positions of the NOSB. 

Simply put, the process of making CSL --the wet milling countercurrent process-- is different 

than the natural practices that are defined in our standards, expressly because the process 

requires adding a synthetic chemical to an otherwise natural steeping/lactic acid fermentation 

process to effect a chemical change, necessary for the end product to be created. So, even 

though this process involves corn and a steeping process, the end result would not get that 

product to where its manufacturer wants without the introduction of a synthetic chemical that 

breaks chemical bonds and manipulates corn to turn it into something else with distinct 

functionality. And USDA researchers at the Agricultural Research Service (who do not have a 

financial interest in this discussion) have confirmed to the Crops Committee that CSL could not 

be created naturally with biological activity alone or as is allowed in what we have until now 

understood to be the nonchemical processes, as stated in the organic Rule: “cooking, baking, 

curing, heating, drying, mixing, grinding, churning, separating, extracting, slaughtering, cutting, 

fermenting, distilling, eviscerating, preserving, freezing, chilling, or otherwise manufacturing 

and includes the packaging, canning, jarring, or otherwise enclosing food in a container.” 

The question is not whether CSL is a good product. 

The question before us is whether CSL is synthetic since it is created through chemical change 

which requires the introduction of a synthetic chemical ingredient. We have been told that CSL 

is composed of proteins, amino acids, carbohydrates, organic acids (such as lactic acid), 

vitamins, minerals and water. All this is true. We are told that these components are all readily 

utilized by animals and microorganisms. And, we’re told that CSL is a nutrient rich product that 

has been safely used as a component in livestock feed, fertilizers, and soil conditioners for 

many years. 

The minority does not dispute this. However, all these valuable assets do not make CSL 

nonsynthetic. The minority believes that this is really all you need to know: a synthetic 

chemical introduced into a mixture with an agricultural material forces a change in the 

chemistry of that agricultural material in a way that would not occur through natural means. 

You don’t really need to go further than that. However, we can shift to the underlying policy of 

the NOSB that establishes CSL as a synthetic product and all future products that we should 

review to ensure that the standards of the statute and National List are met. What follows are 

the policies as they apply to CSL. 
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We come to the minority opinion by following the NOSB’s process 

The minority opinion is based on the policies of the NOSB and the standards that have been 

developed over time. Here is our thinking, as it relates to the policies and definitions of the type 

of chemical change (brought on by the introduction of a chemical substance, or not occurring 

as a result of some natural process). 

The classification of materials recommendation adopted by the board in November 2009 

established three guiding principles for determining whether a substance is synthetic or nonsynthetic: 

 The classification of a material is determined by both the source of the inputs and the 

process used to make the material. 

 The same material can be agricultural, non-synthetic or synthetic depending on source 

and process. 

 If a material is processed such that it is classified as synthetic then the material is 

classified as synthetic regardless of source. A material of this type would most correctly 

be referred to as an “agriculturally sourced material which has been processed in such a 

way as to classify the material synthetic.” Materials that are manufactured in full 

compliance with the final rule are outside the scope of this principle; their status with 

regards to use in organic is not affected by this recommendation. 

These guiding principles are central to the classification of corn steep liquor. We have a 

material whose source is nonsynthetic, however, the source is only the first issue of concern 

under current standards. The process adopted by the board requires us to look at the 

processing applied to the source material as well. In this case, corn is an agricultural material 

(nonsynthetic), and the standard requires an assessment of the wet milling process to which 

the corn is subjected to determine whether it should be classified as synthetic. 

The NOSB’s classification of materials recommendation also stated: 

It is our intent through this recommendation that a material would be classified as 

synthetic when: 

 The source of the material is not “from mineral, plant, or animal matter” (from the 

definition of nonsynthetic) and is not a “substance created by naturally occurring 

biological processes” (from the definition of synthetic) or; 

 The process used to manufacture the material is synthetic (per the definition of 

synthetic and clarifying definitions in our recommendation) or; 

 The material contains, at a significant level, a synthetic substance not on the 

National List of allowed synthetics. (p.5 of 13, Nov. 2009) 

In April 2010, the board adopted an addendum to the classification of materials 

recommendation that sought to clarify the application of the guiding principles. It said, in part: 

It is our belief that chemical changes that occur when an agricultural material is processed 

by itself, or in combination with other agricultural materials, the resulting material should 
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continue to be classified as agricultural. Clearly chemical change happens in these cases, 

if looked at from a purely chemistry perspective, but from a consumer perspective these 

materials are agricultural. The committee differentiates between these cases and those 

when an agricultural material is processed with a non-agricultural material, whether 

synthetic or non-synthetic. In these latter cases, if chemical change occurs, the resulting 

material would be classified as synthetic. (p.1 of 19, April 2010) 

OFPA defines synthetic: 

Synthetic is defined as “a substance that is formulated or manufactured by a chemical 

process or by a process that chemically changes a substance extracted from a naturally 

occurring plant, animal, or mineral sources, except that such term shall not apply to 

substances created by naturally occurring biological processes” (§2103 (21)). 

And chemical change is defined, 

Chemical Change An occurrence whereby the identity of a substance is modified, such 

that the resulting substance possesses a different distinct identity (see related definition 

of “substance”) Processing, as defined in §205.2, of agricultural products using 

materials allowed on the applicable section of the National List (i.e., §205.601 for crops, 

§205.603 for livestock and §205.605 / §205.606 for handling), does not result in 

chemical change as it applies to classification of materials. (April 2010, underlined 

rejected by NOP) 

And substance, 

Substance An element, molecular species, or chemical compound that possesses a 

distinct identity (For example, a distinct identity may be demonstrated through the 

material having a separate Chemical Abstract Service (CAS) number (in some cases 

the same material may have multiple CAS numbers), Codex International Numbering 

System (INS) number, or FDA or other agency standard of identity). (p.10 of 19, April 

2010) 

All of this is background to the following questions: 

1. Is corn steep liquor a different substance from corn, or anything contained in corn? (If 

yes, chemical change has occurred.) 

2. Is breaking disulfide bonds of the corn protein matrix a necessary part of the 

countercurrent wet milling process that results in corn steep liquor as a by-product? 

3. Does the sulfur dioxide (a synthetic substance) that is added to the wet milling process 

break the disulfide bonds in creating the by-product (CSL)? 

If the answer to all these questions is “yes,” the classification of materials policy defines CSL 

as synthetic. 

And, to follow our policy through to its conclusion, regardless of any of the above questions, 

the policy requires the following assessment: 

4. As a result of added sulfur dioxide to the manufacturing process, are there significant 

residues of sulfur dioxide in corn steep liquor? 
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If the answer is “yes,” then CSL is synthetic. If it were the case that no chemical change to the 

source material had occurred as a result of the use of sulfur dioxide, yet if the process of 

producing CSL results in significant (Nov. 2009) residues of sulfur dioxide, then the policy 

requires a determination that the CSL is synthetic.