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Title: ELECTRONIC SPACE CHARGE SYSTEM, AN ALTERNATIVE INTERVENTION STRATEGY FOR BIOFILM REDUCTION

Author
item Arnold, Judy
item Boothe, Dorothy
item Mitchell, Bailey

Submitted to: Biofilms
Publication Type: Abstract Only
Publication Acceptance Date: 8/22/2003
Publication Date: 1/2/2003
Citation: Arnold, J.W., Boothe, D.D., Mitchell, B.W. 2003. Electronic space charge system, an alternative intervention strategy for biofilm reduction. Biofilms, an American Society for Microbiology Conference. Victoria, Canada. October 2003.

Interpretive Summary:

Technical Abstract: The chemical load in food plant sanitation for killing microorganisms could be reduced by the use of alternative non-chemical interventions. Supercharged negative air ionizers have shown potential to effectively reduce airborne and surface microorganisms. Our current studies showed reduced mixed populations from environmental samples, specific pathogens, and bacterial spores. An electrostatic space charge system (ESCS) was used to transfer a negative electrostatic charge to microorganisms on grounded stainless steel coupons at the base of a small chamber. First, bacterial populations from a poultry processing facility were collected, grown as biofilms on coupons, and assessed for susceptibility. Three groups were included: coupons with bacteria that were ionized, coupons with bacteria that were not ionized, and negative controls (coupons without bacteria). The 18-pin ionizer array was operated at -25 kVdc such that ion density at 1 m from the electrode points was 1,000,000 negative ions per cubic cm. Treatment coupons were located approximately 18 cm below the electrode points. Relative humidity was 85%. Treatment with the ESCS resulted in 99.8% kill of mixed populations in 3 hours. Similar treatment of Campylobacter jejuni, Escherichia coli, Salmonella enteritidis, Listeria monocytogenes, and Staphylococcus aureus achieved up to a 99.9% reduction efficiency in 3 hr. Treatment of spores of Bacillus stearothermophilus achieved 96% reduction in 6 hr. For each group, counts of microorganisms were significantly less from ionized surfaces than from non-ionized surfaces. The ESCS does not produce measurable ozone, is non-chemical, and could have an impact on the microbial load in a food processing facility.