Submitted to: Journal of Food Protection
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/30/2006
Publication Date: 1/30/2007
Citation: Fan, X., Fett, W.F., Mitchell, B.W. 2007. Effects of negative air ions on escherichia coli atcc 25922 inoculated onto mung bean seed and apple fruit . Journal of Food Protection. 70(1):204-208. Interpretive Summary: Developing and applying food safety intervention technologies that effectively reduce the foodborne pathogen population in various types of fresh and fresh-cut produce are essential for the successful marketing and consumption of produce. There is a need to develop new, effective and simple intervention strategies. It has been shown that negative air ions, commonly produced via high voltage discharging, reduce airborne microorganisms. The effect of negative air ions on microorganisms on fruits and vegetables has not been investigated. In this study we tested the efficacy of negative air ions for sanitizing mung bean sprout seed and apples. Mung bean seeds, whole "Gala" apples, and apple slices were inoculated with E. coli ATCC 25922 before being exposed to negative air ions for up to 18 h at room temperature. Our results showed that negative air ions had limited effects on E. coli ATCC 25922 on intact apple surfaces and mung bean seed, and had no effect on the bacteria inoculated on apple slices. Furthermore, there was no additive or synergistic effect between negative air ions and acetic acid vapor. The information may be useful for produce industry seeking to adapt new intervention technology to improve the safety of fresh fruits and vegetables.
Technical Abstract: The effect of negative air ions on the reduction of E. coli ATCC 25922 inoculated on mung bean sprout seed and whole or fresh-cut apple fruit were studied. Mung bean seeds, whole "Gala" apples, and apple slices were inoculated with E. coli ATCC 25922 before being exposed to negative air ions for up to 18 h at room temperature (~23 C). Results showed a less than 0.5 log10 reduction of E. coli on mung bean seed even after 18 h of exposure. The reduction of E. coli on the surface of whole apples increased with increasing exposure time from 0.5 to 3 h, but the maximum reduction was less than 1 log10. Increasing exposure time from 3 h to 18 h did not lead to increased treatment efficacy. No reduction of E. coli was observed on apple slices after 3 h treatments. When the negative air ion system was applied together with acetic acid vapor, no additive or synergistic effect of negative ions on the reduction of E. coli was found. The results suggested that negative air ions had a very limited effect on the population of E. coli on mung bean seed and apples.