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Non-thermal Plasma Treatment of Milk (Phases I - III)

Investigators
Ruan, Roger; Metzger, Lloyd; Chen, Paul
Institutions
University of Minnesota
Start date
2005
End date
2010
Objective
1. Develop and test high efficiency reactors (Phase 1). 2. Study effect of treatments on microbial reduction and physical and chemical properties of milk samples. 3. Investigate the shelf life stability of treated milk samples. 4. Optimize processes. 5. Develop mobile continuous prototype demo system.
More information
Ultra-high temperature (UHT) pasteurization is the thermal treatment used to produce shelf stable milk, but it can degrade its sensory quality. This study will determine if non-thermal technology (non thermal plasma/high electric field) can replace traditional UHT treatments and potentially improve the shelf life of milk without impacting its flavor. Researchers developed an efficient pilot-scale prototype system to validate technology for non-thermal pasteurization of skim milk, and generated sufficient data for FDA approval. Results show that a single pass through the CHIEF apparatus inactivated E. coli O157:H7, Salmonella and Listeria monocytogenes, but was not effective against spores of B. cereus. A serial treatment of two consecutive passes enhanced inactivation, but reduction numbers were better for Salmonella than Listeria and E. coli. Milk treated with the CHIEF lasted up to 14 days before exceeding the established total bacterial limits (4.3 log units), while the untreated control milk had a shelf life about 7 days.
Funding Source
Dairy Research Inst.
Categories
Escherichia coli
Listeria