Date of Award:
Master of Science (MS)
Nutrition, Dietetics, and Food Sciences
Donald J. McMahon
The Western Dairy Center at Utah State University funded this project as part of its BUILD Dairy program with support from the dairy farmers of Idaho, to investigate the problem of splits that form in cheese during storage. The bacteria, Lactobacillus wasatchensis had previously been identified as a cause of unwanted gas production in cheese and the defects then make the cheese unsuitable for cutting into slices.
The project team proposed a two-year, $150,912 project to investigate methods for determining the presence of this bacterium in cheese by extracting DNA from the cheese and looking for DNA that was specific to Lactobacillus wasatchensis. The project identified a suitable method for extracting DNA and demonstrated that methods that extract DNA directly from the cheese are not as repeatable or reliable as a method that first separates and collects the bacteria from the cheese and then extracts the DNA.
While the detection limit for identifying Lactobacillus wasatchensis in cheese of 100,000 cells per gram, was not any lower than that which can be achieved using plating methods, this work provides the benefit of laying groundwork for selection of a NDA extraction method for use with cheese. Further research can now be applied to lower this detection limit so this bacterium can be identified in cheese earlier and thus reduce the problem of slits and cracks and provide a higher value of the cheese to the manufacturer.
Allen, Tyler, "Comparison of Methods for Extracting Lactobacillus wasatchensis DNA from Broth Media, Milk, and Cheese for Subsequent PCR-Based Analyses" (2018). All Graduate Theses and Dissertations. 7332.