Recipient Organization
CORNELL UNIVERSITY
(N/A)
ITHACA,NY 14853
Performing Department
Food Science
Non Technical Summary
Microbial food spoilage causes 48 million illnesses and costs $77.7 billion dollars per year in the U.S. Microbial spoilage in beer and wine can sometimes have negative health impacts, but impacts are more often reflected as economic losses (entire batches of beer or wine are ruined due to exploding bottles or unpleasant aroma and flavors). One approach to control microbial spoilage is to limit an essential nutrient, such as iron, thus preventing microbial spoilage organisms from growing. This proposal describes a research project aimed at using a natural product (yeast) to remove iron from wine and beer, making the products more microbially stable and less likely to have spoilage issues. This research could not only provide a method for controlling microbial spoilage, but do so in a way that aligns well with the current public interest in "natural" approaches in food/beverage production.The wine and brewing industries in New York, and generally in the United States, are growing along with increased public consumption of wine and beer. The work outlined in this proposal has potential value to winemakers and brewers within the state of New York and throughout the country. By publishing the results of this work in scientific journals, and presenting it at conferences/symposia, the knowledge will be a shared resource available to anybody, and these results will be easily translatable into a commercial product by the large yeast supply companies that would only need to make a small change to their workflow.
Animal Health Component
(N/A)
Research Effort Categories
Basic
15%
Applied
(N/A)
Developmental
85%
Goals / Objectives
Microbial food spoilage causes 48 million illnesses and costs $77.7 billion dollars per year in the U.S. Microbial spoilage in beer and wine can sometimes have negative health impacts, but impacts are more often reflected as economic losses (entire batches of beer or wine are ruined due to exploding bottles or unpleasant aroma and flavors). One approach to control microbial spoilage is to limit an essential nutrient, such as iron, thus preventing microbial spoilage organisms from growing. This proposal describes a research project aimed at using a natural product (yeast) to remove iron from wine and beer, making the products more microbially stable and less likely to have spoilage issues. This research could not only provide a method for controlling microbial spoilage, but do so in a way that aligns well with the current public interest in "natural" approaches in food/beverage production.The wine and brewing industries in New York, and generally in the United States, are growing along with increased public consumption of wine and beer. The work outlined in this proposal has potential value to winemakers and brewers within the state of New York and throughout the country. By publishing the results of this work in scientific journals, and presenting it at conferences/symposia, the knowledge will be a shared resource available to anybody, and these results will be easily translatable into a commercial product by the large yeast supply companies that would only need to make a small change to their workflow.The major goals of this project are as follows:Identify and optimize growth conditions required to starve yeast cells for ironExamine and optimize the use of iron-starved yeast to remove iron from multiple types of solutions: prepared solutions of iron, wine, and beerExamine the ability of iron-depleted wine and beer to support growth of common spoilage organismsExamine the ability of encapsulated, iron-starved yeast to reduce iron in wine and beer
Project Methods
The methods listed below are associated with each of the major goals of the project.Identify and optimize growth conditions required to starve yeast cells for iron: To begin we will prepare standard yeast (S. cerevisiae) growth media that lacks iron and examine time required until cells cease growth due to iron starvation. Growth will be assessed using plating for viable colony forming units. Iron starvation will be confirmed in multiple ways. First, the total number of cells in a starved culture should be less than in a non-starved, control culture. Second, a number of genes are known to turn on in response to iron starvation; most of them produce proteins that bind and import iron. We will measure activation of these genes by measuring levels of fluorescently-tagged proteins produced in iron-starved conditions vs. control conditions. Growth conditions will be optimized to minimize the media supply costs and minimize the time required to produce iron-starved yeast cells.Examine and optimize the use of iron-starved yeast to remove iron from solution: After preparing iron-starved yeast cells, these cells will be placed into control solutions containing different quantities of iron, and a variety of different beer and wine samples. Iron levels in each solution will be measured both before yeast addition, and at multiple time-points, to determine the speed and efficiency of iron scavenging. Iron measurements will be performed using a flame emission spectrometer available in the department. Optimization parameters include the relationship between cell number and total iron removed, and amount of time required for maximum iron removal.Examine the ability of iron-depleted wine and beer to support growth of common spoilage organisms: Using the optimized protocol developed in #3, we will prepare a variety of iron-depleted beer and wine (including non-depleted controls). To these samples we will add common wine and beer spoilage microorganisms and examine their ability to grow/survive. Growth and survival will be assessed by plating for viable colony forming units. In addition to growth and survival, we will also assess whether or not these spoilage organisms are able to cause typical sensory defects; for example, Brettanomyces spoilage in wine can produce band-aid/barnyard aromas.Examine the ability of encapsulated, iron-starved yeast to reduce iron in wine and beer: To be most useful as a microbial spoilage control in the wine and beer industries, the iron-starved yeast cells would be encapsulated. This encapsulation prevents growth of the iron-starved yeast and makes removal very easy because the encapsulated form is larger and heavier. Encapsulated yeasts are routinely prepared and used in the wine industry as a way to re-start slow/stopped fermentations, so major yeast suppliers already have the mechanism in place to produce these cells. We will encapsulate the iron-starved yeast cells and repeat the optimized experiments performed in #1-3 to validate the results in encapsulated yeasts.