U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 close



Research
                Research Home
                            National Programs
                            Research Projects
                            Scientific Manuscripts
                            International Engagement
                            Scientific Software/Models
                            Databases and Datasets
                            Office of Scientific Quality Review
            Media
                News & Features
                            Multimedia
                            Briefing Room
                            Down on the Farm
                            Press Room
                            Science in Your Shopping Cart
                            Scientific Discoveries
                            Tellus
                            Under the Microscope
            About ARS
                About ARS Home
                            Staff Directory
                            Labs and Research Centers (Map)
                            Headquarter Offices
                            Organizational Chart
                            Employee Services (REE Employees Only)
                            Office of Outreach, Diversity, and Equal Opportunity
            Work With Us
                Work With Us Home
                            ARS Vacancies at USAJOBS
                            Careers at ARS Information
                            Scientific Collaborations
                            Extramural Agreements
                            1890 Faculty Research Sabbatical ProgramSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home News & Events News Articles Research News 2003





- ARS News & Events
- AgResearch Magazine
- Image Gallery
- News
- Search News & Events
- Pesticide Drift May Endanger Pollinators
- ARS Seeks a Fire Ant Fix
- Scientific Discoveries 2024
- ARS Featured Photos
- Down on the Farm
- Facebook Live Events
- Food and Nutrition Research Briefs
- News Archive
- Science in Your Shopping Cart
- Scientific Discoveries
- Social Media
- Under the Microscope
- AgResearch magazine
- ARS at Work
- ARS Memorial Lectures
- ARS Science Hall of Fame
- Citrus Disease (Huanglongbing)
- Contact Office of Communications
- Plant Hardiness Zone Map
- Mobile Apps
- Public Affairs Contacts
- Publications and Other Resources
- USDA Blog
- Videos

Archived Page
 This page has been archived and is being provided for reference purposes only. The page is no longer being updated, and therefore, links on the page may be invalid.
 Radio Frequencies Blast Bacteria in Fruit Juice By Jim CoreMarch 27, 2003 Radio waves may be invisible, but they enrich life in many ways. Without them, radios, televisions, cellular phones and global positioning systems wouldn't be possible. Now, an Agricultural Research Service scientist is using them to make fruit juice safer. The radio frequency electric fields (RFEF) technique inactivates bacteria in apple juice without heating it. Although RFEF has been studied for more than 50 years as a pasteurization method, this is the first confirmed instance of a successful inactivation of bacteria using this technique in fruit juice. Conventional pasteurization using heat can affect the nutrient composition and flavor of fruit and vegetable juices. The RFEF technique itself is nonthermal because the inactivation is not produced by heat. However, when moderate heat is applied, the combined effect is much greater than the effect of either process used alone. David Geveke, a chemical engineer in the ARS Food Safety Intervention Technologies Research Unit at the agency's Eastern Regional Research Center at Wyndmoor, Pa., built a specially designed treatment chamber to apply high-intensity RFEF to apple juice. Researchers conducted experiments using Escherichia coli K12, a harmless form of bacteria used by researchers to study similarly behaving pathogenic strains, such as E. coli O157:H7. Apple juice was exposed to electrical field strengths of up to 20 kilovolts per centimeter and frequencies in the range of 15 to 70 kilohertz, using a 4-kilowatt power supply. For some perspective, lightning occurs at field strengths of 30 to 40 kilovolts per centimeter, and 20 kilohertz is considered to be in the upper range of human hearing. Increasing the field strength and temperature, as well as decreasing the frequency, enhanced inactivation, according to Geveke. E. coli in juice at 50 degrees Celsius (about 122 degrees Fahrenheit) was reduced by 99.9 percent. RFEF could provide an alternative to pasteurization by heat. According to Geveke, the RFEF process could be used to treat heat-sensitive products such as fruit juices, vegetable juices and liquid egg products. ARS is the U.S. Department of Agriculture's chief scientific research agency.


Return to top


Research
                            Media
                            About ARS
                            Work With Us


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov