Bacteria could improve dairy taste

Basic sequencing research could lead to tastier, smoother, more-nutritious yogurt or fat-free cheese that feels and tastes more like regular cheese. Bob Hutkins, a University of Nebraska, Lincoln, food scientist, is studying Streptococcus thermophilus as part of the Lactic Acid Bacteria Genome Consortium, a group of 12 scientists from several universities. They are working to identify the genetic makeup of 11 naturally occurring bacteria that are among the most commercially important to food production.

Sequencing means finding the order of DNA pieces in a gene. During the initial sequencing process, which was done in conjunction with the Department of Energy's Joint Genome Institute, computers identified which DNA pieces fit together to make each gene. S. thermophilus has 2,000,000 such pieces.

Using the sequencing information, Hutkins will try to determine the roles of different genes in S. thermophilus, which is used in dairy fermentations. It is responsible for good flavor in cheese and contributes to yogurt's texture. Understanding the genetic functions and harnessing desirable genes could lead to fat-free cheese with the same mouth feel as regular cheese or allow scientists to create an organism that is resistant to viruses that might delay or interfere with fermentation.

For example, some strains of this bacterium naturally produce small amounts of a substance similar to thickening agents used in low-fat cheese. Knowing the DNA sequence responsible for this substance could help researchers enhance its production in cheese.

"This individual research could take years, but it is important to the fermented food and beverage industry," Hutkins maintains. "The sequencing opens huge doors for studying bacteria individually and in relation to others."

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