Production in Dairy-based Growth Media and Concentration by Freeze Drying of Bacteriocin Preparation from Lactic Acid Bacteria to Inhibit Select Pathogens

NON-TECHNICAL SUMMARY: Foodborne diseases remain a major cause of morbidity and mortality. An estimated 76 million cases of foodborne illness, with 325,000 hospitalizations, occur each year in the United States, costing between $6.5 and $34.9 billion in medical care and productivity. The proposed project investigates the production of bacteriocins from Lactic Acid Bacteria (LAB) in dairy-based growth media, their concentration by freeze drying, and their use to inhibit select foodborne pathogens, including Listeria monocytogenes, Staphylococcus aureus, and Enterobacter sakazakii. <P>APPROACH: Lactic acid bacterial bacteriocins, other than Nisin, that are active against Listeria monocytogenes and Staphylococcus aureus will be identified. The production of select bacteriocins in Cheddar cheese whey will be investigated and optimized as necessary. The effectiveness of these bacteriocins as dairy-based ingredients with biopreservation capabilities in select food products will be evaluated. In addition, the effectiveness of Nisin in controlling the growth of Enterobacter sakazakii and its use as a biopreservative in milk-based infant formula will be investigated. <P>
PROGRESS: 2007/01 TO 2007/12<BR>
OUTPUTS: The most significant dissemination activities for the project so far include: 1. An abstract published in the abstract book for the Society for Industrial Microbiologists Annual Meeting and Exhibition (2007); and 2. A poster presentation at the Society for Industrial Microbiologists Annual Meeting and Exhibition (2007) <BR>PARTICIPANTS: The following individuals have been participating in the project: Dr. Gulhan Unlu (Faculty), Dr. Galina Dimitrieva-Moats (Research Support Scientist I), and Meghan Smith (Graduate Student). Meghan Smith, an M.S. candidate in the Department of Food Science and Toxicology at the University of Idaho, has been trained the areas of food microbiology, microbial food safety, and biopreservation of foods. Dr. Dong-Hyun Kang from Washington State University is a collaborator on the project. He has provided Dr. Unlu's research group with various Enterobacter sakazakii strains. <BR>TARGET AUDIENCES: The project deals with the production of various bacteriocin preparations from dairy-based growth media and the concentration of these preparations by freeze drying. The freeze-dried bacteriocin preparations will be used to inhibit select foodborne pathogens, including Listeria monocytogenes, Staphylococus aureus, and Enterobacter sakazakii. The relevant agencies of the US government can utilize the findings of the project to make recommendations on the appropriate incorporation of bacteriocins into select food products. The successful use of bacteriocins as biopreservatives in foods would help reduce the number of foodborne illness related hospitalizations, deaths, and economical loss due to medical expenses, lost income and productivity, cost of litigation and penalties, and loss of trade, benefiting the US government, the food industry, and the consumer. <BR> PROJECT MODIFICATIONS: None
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IMPACT: 2007/01 TO 2007/12<BR>
Foodborne diseases remain a major cause of morbidity and mortality. An estimated 76 million cases of foodborne illness, with 325,000 hospitalizations, occur each year in the US, costing between $6.5 and $34.9 billion in medical care and productivity. Incidence of foodborne illness is documented through FoodNet, a reporting system used by the US public health agencies that captures foodborne illness in over 13% of the population. Data are only available for confirmed cases, and it is generally accepted in the scientific community that the true incidence of foodborne illness is underreported. Mankind has used lactic acid bacteria (LAB) for thousands of years in the production of fermented foods because LAB produce desirable changes in flavor and texture and inhibit pathogenic and spoilage microorganisms. In fermented foods, LAB inhibit undesirable microorganisms by decreasing pH, competing for nutrients, and producing a variety of antimicrobial components, including organic acids, hydrogen peroxide, and bacteriocins. Although the development and optimization of LAB and bacteriocins as biopreservatives to control foodborne pathogenic bacteria remains a major focus of several laboratories involved in research related to food safety, the effectiveness of most bacteriocins has not yet been fully explored in foods. In spite of the potential negative impact of various food components on biological activity, bacteriocins can find applications in many products, including dairy, meat, vegetable, fruit, bakery, and fishery products. It has been estimated that Listeria monocytogenes causes 2,493 foodborne illnesses and 499 deaths every year in the US while staphylococcal food intoxication is estimated to cause 185,000 cases of foodborne illness annually. The prevention of even a very small percentage of these foodborne illness cases via the use of bacteriocins as biopresevatives would help reduce the number of foodborne illness related hospitalizations, deaths, and economical loss due to medical expenses, lost income and productivity, cost of litigation and penalties, and loss of trade. Production of bacteriocins from LAB in commercially available growth media is usually a costly process. Therefore, the process can be carried out in food-grade and inexpensive growth media such as dairy-based media. Whey is a by-product of cheese manufacturing process and contains 55% of the nutrients present in milk. Production of value-added products from cheese whey, such as whey powder, lactose, whey protein, biogas, bioethanol, and bacteriocins, represents an attractive area for research. Idaho's dairy industry is one of the largest agricultural industries in the state with cheese production being a major milk outlet. Appropriate technologies and associated processes can be developed to allow the cheese industry within the state of Idaho and the nation to better utilize cheese whey by converting it to value-added products including the bacteriocins from LAB.