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Perspective:
Dairy Research

The use of microfiltered milk in standardized cheese

John Lucey

John Lucey, director of the Wisconsin Center for Dairy Research at the University of Wisconsin-Madison, contributes this column for Cheese Market News®.

The use of microfiltered (MF) milk in standardized cheese has recently become a point of contention in the U.S. dairy industry, even though the technology is widely used in other parts of the world. Applauded by many as an innovative method in dairy processing, at this time FDA does not allow MF because it believes that MF milk is an “altered” form of milk that does not fit within the definition for standard of identity cheeses (Federal Register, Docket No. 2000P-0586). In contrast, ultrafiltration (UF) has become an allowable and frequently used method within the dairy industry, making it even more difficult to understand the rationale behind the exclusion of MF for cheesemaking. As such, it’s time for the industry to bring science back into the conversation.

In order to understand this difference of opinion, it’s important to first understand the fundamentals of filtration.

At a very basic level, MF and UF are membrane filtration processes that separate milk components based on molecular size. MF retains fat and larger proteins, such as casein, while allowing lactose, minerals, small proteins and non-protein nitrogen (NPN) to pass through. UF, on the other hand, retains both casein and whey proteins, while lactose and soluble minerals pass through. While both change the composition of milk, UF is currently considered “milk” by FDA because the process does not alter the casein-to-protein ratio in the milk. MF, on the other hand, permeates some of the whey proteins, thereby changing the casein-to-whey protein ratio of the milk, which is not currently allowable for standardized cheeses.

This change in casein-to-whey protein ratio is the main reason that regulatory agencies give for opposing the use of MF milk in cheesemaking. Essentially, the belief is that by shifting this ratio in milk, MF is somehow altering the nutritional content of the final cheese product and deceiving consumers. This is not the case, however, as whey protein is easily lost in the whey stream anyway and is only present at negligible levels in cheese (less than 0.3 percent by weight). So, any adjustment in the casein-to-whey protein ratio would have only a tiny impact on the whey protein level in the final cheese.

It is important to note that allowable and very common practices, such as high heat treatment of milk, curd washing, addition of nonfat dry milk or the addition of concentrated milks, have a much greater potential to change the concentration of whey protein in cheese than the MF process.

Meanwhile, FDA’s argument is that because UF retains the original casein-to-protein ratio in milk, UF milk is still milk, even though its lactose and mineral content has been changed.

The reality of the situation, however, is that much like UF, MF simply rearranges the steps in cheesemaking.

MF essentially takes out some of the soluble components that would be lost in the whey when it is drained during the cheesemaking process. Studies by CDR (e.g., Govindasamy et al. 2007, Journal of Dairy Science, 90:4552–4568) have demonstrated that the use of MF does not impact cheese quality. In fact, because the milk is concentrated, the amount of whey proteins in the cheese is actually slightly higher than cheese made with non-MF concentrated milk even though 20 percent of the whey proteins have been removed from the milk. Cheeses made with UF milk, on the other hand, tend to have an even higher quantity of whey proteins than cheese made from non-concentrated milk. Therefore, cheeses made from either UF or MF milk are not nutritionally inferior to cheeses made from non-concentrated milk so there is no basis for concern that the public is somehow being deceived by an inferior product.

Another reason for the interest in applying MF to cheesemilk is that it creates an innovative new product called milk-derived whey (or native whey). This whey and the products produced from it — such as lactose and whey protein concentrates — have a cleaner flavor and better heat stability. Since milk-derived whey comes directly from milk and does not go through the cheesemaking process, it also lacks annatto coloring, rennet and starter culture by-products, all of which can cause unwanted color or flavor issues in whey powders during storage. Milk-derived whey also contains less fat than a traditional whey protein concentrate, which allows for a clearer appearance in food applications, making milk-derived whey an excellent choice for clear beverages. MF also is very useful to cheesemakers since the MF process allows for direct control of the casein concentration in milk, making it easier to have very consistent coagulation and uniform cheese yields.
Unfortunately, the current views of FDA on the use of MF in standardized cheeses greatly impairs the implementation of this innovative technology in the United States. It also puts the United States at a competitive disadvantage to the rest of the world which is actively exploring the opportunities around the use of MF milk. That’s why it is essential that the U.S. industry takes another look at this issue including petitioning FDA to allow MF for cheesemaking. In the meantime, cheesemakers could request from FDA a temporary market permit (TMP) to produce and market standardized cheeses made from MF milk. FDA could require labeling of the cheese to say microfiltered milk. In essence a TMP is a short term variance that the FDA can provide to cheesemakers to evaluate a process/product.

It’s time we bring science back into the discussion and push for regulations that are backed by facts. It’s obvious that the MF process is simply a different way of doing things in a modern dairy plant.

CMN

The views expressed by CMN’s guest columnists are their own opinions and do not necessarily reflect those of Cheese Market News®.

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