Page Banner

United States Department of Agriculture

Agricultural Research Service

Title: Use of Negative Ari Ionization for Reducing Bacterial Pathogens and Spores on Stainless Steel Surfaces

Authors
item Arnold, Judy
item Boothe, Dorothy
item Mitchell, B. - USDA/ARS SEP

Submitted to: Journal of Applied Poultry Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 27, 2003
Publication Date: January 1, 2004
Citation: Arnold, J.W., Boothe, D.D., Mitchell, B.W. 2004. Use of negative air ionization for reducing bacterial pathogens and spores on stainless steel surfaces. Journal of Applied Poultry Research. 13:200-206.

Interpretive Summary: The use of chemicals in food plant sanitation for removing and killing microorganisms could be reduced by the use of non-chemical methods. Negative air ionization is a new technology that has shown potential to effectively reduce airborne and surface microorganisms. An electrostatic space charge system (ESCS) generates a strong negative charge that is transferred to bacteria on stainless steel coupons. Current studies have shown reduction of mixed populations from environmental samples, bacterial pathogens, and bacterial spores. The levels of biofilm bacteria on stainless steel surfaces were decreased with a 99.8% efficiency. In this study, the power of the charge was varied by adjustment of the voltage and/or moving the ground plane closer or further from the electrode points. Counts of bacterial pathogens were less from ionized surfaces than from non-ionized surfaces. Treatment of selected bacteria of food safety importance achieved a 99.9% reduction efficiency in 3 hrs. Treatment of selected spores of Bacillus stearothermophilus achieved a 99.8% reduction efficiency in three hours. These data indicate that the ESCS could have an impact in a facility by direct killing of bacteria and spores on surfaces.

Technical Abstract: The use of chemicals in food plant sanitation for removing and killing microorganisms could be reduced by the use of alternative non-chemical interventions. Negative air ionization is a new technology that has shown potential to effectively reduce airborne and surface microorganisms. Current studies have shown reduction of mixed populations from environmental samples, bacterial pathogens, and bacterial spores. In our preliminary work, a small chamber with an electrostatic space charge system (ESCS) was used to transfer a strong negative charge to bacteria on stainless steel coupons. The levels of biofilm bacteria on stainless steel surfaces were decreased with a 99.8% efficiency. In this study, ion density was varied by adjustment of the ionizer power supply voltage and/or moving the ground plane closer or further from the electrode points to achieve ion densities at 1 m from 103 to106 negative ions/cm3. Relative humidity was maintained at 85%. Counts of bacterial pathogens were significantly less from ionized surfaces than from non-ionized surfaces. Treatment of Campylobacter jejuni, Escherichia coli, Salmonella enteritidis, Listeria monocytogenes, and Staphylococcus aureus achieved up to a 4 log reduction with a 99.9% reduction efficiency in 3 hr. Treatment of spores of Bacillus stearothermophilus achieved a 3 log reduction with an 99.8% reduction efficiency in three hours. These data indicate that the ESCS could have an impact on the microbial load in a facility by direct killing of bacteria and spores on surfaces.

Last Modified: 4/20/2014
Footer Content Back to Top of Page