Microfiltrating Milk

Dairy Foods, Feb, 2001 by Donna Berry

The relationship of whey to cheese, with the former considered a by-product of the latter, is changing as a result of on-going research at Cornell University, Ithaca, N.Y. Scientists here believe that by reversing the cheesemaking process, the value-added item coming out of a cheese plant is now the milk proteins separated from the liquid milk prior to it being used to make cheese.

With funding from America's dairy farmers, which is managed by Dairy Management Inc., investigators discovered that filtering these proteins from liquid milk instead of the whey stream yields purified milk serum protein ingredients and concentrated native casein that contain none of the colorants, enzymes and cultures used during cheese manufacture.

Product developers can expect a more consistent and purer protein ingredient through this process. Currently, food manufacturers, especially those concerned with maintaining Kosher standards, need to be sensitive to the type of cheese from which a whey protein concentrate originates.

The pore size of the filter enables processors to customize the composition of the permeate and the retentate. This process has the potential to improve plant efficiencies in the conversion of milk to cheese. Low concentration factor retentates can be used to fortify unfiltered milk, which would help lower cheese manufacturing costs. Using a higher concentration factor approach would allow for an even more efficient continuous cheesemaking process, with little or no whey drainage from the cheese, according to Sy Rizvi and Dave Barbano, Cornell professors associated with the project.

In both cases, a milk serum protein concentrate (SPC) would be produced from the microfiltration permeate from the liquid milk and would be a higher value co-product of cheesemaking than traditional whey products.

"Functionally and nutritionally, this SPC differs from traditional whey products," says Barbano. "There could be an entire new spectrum of uses for this ingredient, and those uses remain to be discovered."

From a financial perspective, the higher degree of purity and consistency achieved through this process translates into a greater profit potential because processors should be able to command a better price structure, as compared to other dairy powders in the marketplace.