Skim milk powder (SMP) and nonfat dry milk (NDM) are often confused and sometimes combined like they were the same thing. They are similar – but in some ways, they are very different. As the dairy industry transitions from a national business to a global business, the U.S. dairy industry must transition to international standards to compete.

While there are numerous dairy products with similar but different international and U.S. standards, this article will concentrate only on the difference between the international standard of SMP and the U.S. standard of NDM.

There were two prior articles this year in Progressive Dairyman that form the background for this article.

The first article explored the impact of free-trade agreements on the U.S. dairy industry (International free trade agreements and their impact on U.S. dairy prices), and the second article discussed the differences between the international and U.S. standards for maximum allowed somatic cell count (How far off are we from global somatic cell count standards?).

The starting difference between SMP and NDM is who sets the standards for each product. NDM is defined by the USDA/FDA in the Federal Code of Regulations (FCR). SMP is defined by the Codex Alimentarius, an international organization headquartered in Geneva, Switzerland. These two organizations also control the standards for product labeling.


What is Codex Alimentarius? The name is Latin for “Food Code,” and its function is to provide “harmonized” international food standards. The U.S. and 186 other countries are members of Codex. The purpose is to set standards that allow food products to be “harmonized” so they can be traded and to ensure that the products are suitable for human consumption.

The Food and Agricultural Organization (FAO) of the United Nations and the World Health Organization (WHO) established Codex in 1963. The FAO is located in Rome, Italy, and the WHO is located in Geneva, Switzerland.

While these are all international organizations, they are also all European-based. The World Trade Organization (WTO), which is the controlling organization for trade agreements, is also based in Geneva, Switzerland, and depends on Codex standards for trade agreements.

Who really controls Codex? This is a very controversial subject. Obviously, by geographic standards, Codex would appear to be an organization with European roots. However, many complain that the U.S. dominates the Codex agenda. The complexities of getting all countries to agree to a standard makes change difficult and slow.

Over time, U.S. and Codex standards may become harmonized. Many other countries are working toward the same end. However, this is a slow process and progress can only be measured in years – and sometimes decades. In the meantime, the U.S. must find ways to walk down both paths, the one based on U.S. standards and one based on international standards.

In other words, that means the U.S. dairy industry must be able to make products that comply with the FDA/CFR standards as well as products that comply with Codex standards for the international markets.

So how do the specifications differ? Both products are basically dried skimmed milk. Both products are typically spray-dried and have standards based on three different levels of drying heat. However, because of the differences in some of the specifications, the products are far from interchangeable.

The major standards are shown in Table 1 and are often referenced as the differences between products. However, the differences go much deeper.

Based on total protein

NDM is commonly considered a U.S. product, where SMP is the international standard. Because the U.S. has started participating in the international dairy markets, it must produce SMP to meet competitive standards in the global markets.

However, there are standards for NDM that SMP does not meet, so the U.S. must also produce NDM. The other large dairy exporters produce essentially one product, SMP, for local use as well as international markets.

What makes SMP inappropriate for some U.S. needs? As an example, the Codex allows for addition of milk protein concentrates to increase protein to the level needed to meet the 34 percent standard.

That means SMP does not meet the U.S. standards for cheese manufacturing when used as an ingredient in the manufacture of some cheeses.

One obvious question is: “Why not just make a product that meets both specifications?” The biggest issue is the minimal protein standard. The addition of protein concentrates is allowed in SMP in order to meet the 34 percent standard.

For NDM, because there is no minimal standard for protein, supplementation with protein concentrates is not required and is not done. Therefore, only NDM can be used in dairy products that do not allow protein concentrates.

The following example demonstrates the analytical difficulty in making a product that consistently meets both standards. The standard formula used by the FDA for skim milk is 3.1 percent true protein and 5.9 percent other solids.

Because the Codex standard uses nitrogen concentration to determine protein, the 3.1 percent true protein would translate to roughly 3.25 percent total protein. Protein would then calculate to be 35.5 percent of solids, in line with the minimal Codex standard of a minimum of 34 percent protein.

These numbers are, of course, “average” numbers, and lower protein levels do occur, especially in the heat of summer. If protein falls by more than 1.5 percent, and other solids remain the same, it can be difficult to meet the 34 percent standard without supplementation.

To meet both standards and ensure economical production, dairy producers must work to increase milk protein production levels through techniques like amino acid balancing.

There are other parameters that must also be reconciled such as bacterial count. The U.S. produces two grades of NDM: Standard and Extra Grade. To harmonize SMP and NDM, the NDM criteria for “Extra Grade” must be met.

Production of SMP in the U.S. has grown to about one-third the volume of NDM. Obviously, SMP is a major production item in the U.S.

To be able to compete in international markets, the U.S. must be able to meet international standards with minimal cost.

There is no doubt that U.S. transitions to international standards are difficult and require changes in processes throughout most all of the steps in producing and processing milk. However, the transition to international standards seems to be inevitable. The best way to successfully transition is usually to get an early start.  end mark

John Geuss