Article | 12. 2014 Vol. 32, Issue. 6
An Ozone Micro-bubble Technique for Seed Sterilization in Alfalfa Sprouts



Research Institute of Agriculture and Life Sciences, Seoul National University,1
Department of Plant Science, Seoul National University2




2014.12. 901:905


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The efficacy of ozone micro-bubble water (OMBW) in reducing microbial populations on alfalfa seeds was investigated in this study. We observed the surface of alfalfa seeds using microscopy and found that many cracks and crevices existing on the surface could harbor pathogens. Alfalfa seeds were treated with tap water (TW), micro-bubble water (MBW), ozone water (OW), ozone micro-bubble water (OMBW), and chlorine water (CL) for 5 min, and total microbial population, E. coli and Salmonella spp. colonies were determined. Also, the sterilized seeds were germinated and cultivated for 5 d after sowing to investigate the percentage of germination and the growth of alfalfa sprouts. The treatments with OMBW and CL were most effective in reducing total microbial populations and E. coli was eliminated by OW, OMBW, and CL treatments. CL treatment reduced the percentage of germination and fresh weight of alfalfa sprouts, but OMBW did not cause any negative effects on the germination and growth of alfalfa sprouts. These results indicate that OMBW can be used as an effective sanitizer for eliminating seed-borne pathogens without detrimental effects on seed viability.



1. Buck, J.W., R.R. Walcott, and L.R. Beuchat. 2003. Recent trends in microbiological safety of fruits and vegetables. Plant Health Prog. doi: 10.1094/PHP-2003-0121-01-RV.  

2. Charkowski, A.O., J.D. Barak, C.Z. Sarreal, and R.E. Mandrell. 2002. Differences in growth of Salmonella enterica and Escherichia coli O157:H7 on alfalfa sprouts. Appl. Environ. Microbiol. 68:3114-3120.  

3. Ikeura, H., F. Kobayashi, and M. Tamaki. 2011a. Removal of residual pesticide, fenitrothion, in vegetables by using ozone microbubbles generated by different methods. J. Food Eng. 103:345-349.  

4. Ikeura, H., F. Kobayashi, and M. Tamaki. 2011b. Removal of residual pesticides in vegetables using ozone microbubbles. J. Hazardous Materials 186:956-959.  

5. Michino, H., K. Araki, S. Minami, S. Takaya, N. Sakai, M. Miyazaki, A. Ono, and H. Yanagawa. 1999. Massive outbreak of Escherichia coli O157:H7 infection in schoolchildren in Sakai city, Japan, associated with consumption of white radish sprouts. Amer. J. Epidemiology 150:787-796.  

6. National Advisory Committee on Microbiological Criteria for Foods (NACMCF). 1999. Microbiological safety evaluations and recommendations on sprouted seeds. Int. J. Food Microbiol. 52:123-153.  

7. Rajkowski, K.T. and D.W. Thayer. 2001. Alfalfa seed germination and yield ratio and alfalfa sprout microbial keeping quality following irradiation of seeds and sprouts. J. Food Protection 64:1988-1995  

8. Richardson, S.D., A.D. Thruston Jr., T.V. Caughran, T.W. Collette, K.S. Patterson, and B.W. Lykins, Jr. 1998. Chemical by-products of chlorine and alternative disinfectants. Food Technol. 52:58-61.  

9. Scouten, A.J. and L.R. Beuchat. 2002. Combined effects of chemical, heat and ultrasound treatments to kill Samonella and Escherichia coli O157:H7 on alfalfa seeds. J. Appl. Microbiol. 92:668-674.  

10. Sharma, R.R. and A. Demirci. 2003. Inactivation of Escherichia coli O157:H7 on inoculated alfalfa seeds with pulsed ultraviolet light and response surface modeling. J. Food Sci. 68:1448-1453.  

11. Sharma, R.R., A. Demirci, L.R. Beuchat, and W.F. Fett. 2002. Inactivation of Escherichia coli O157:H7 on inoculated alfalfa seeds with ozonated water and heat treatment. J. Food Protection 65:447-451.  

12. Singh, N., R.K. Singh, and A.K. Bhunia. 2003. Sequential disinfection of Escherichia coli O157:H7 inoculated alfalfa seeds before and during sprouting using aqueous chlorine dioxide, ozonated water, and thyme essential oil. LWT-Food Sci. Technol. 36: 235-243.  

13. Sumikura, M., M. Hidaka, H. Murakami, Y. Nobutomo, and T. Murakami. 2007. Ozone micro-bubble disinfection method for wastewater reuse system. Water Sci. Technol. 56:53-61.  

14. Takahashi, M., K. Chiba, and P. Li. 2007a. Free-radical generation from collapsing microbubbles in the absence of a dynamic stimulus. J. Phys. Chem. B 111:1343-1347.  

15. Takahashi, M., K. Chiba, and P. Li. 2007b. Formation of hydroxyl radicals by collapsing ozone microbubbles under strongly acidic conditions. J. Phys. Chem. B 111:11443-11446.  

16. Urano, K., H. Wada, and T. Takemasa. 1983. Empirical rate equation for trihalomethane formation with chlorination of humic substrates in water. Water Res. 17:1797-1801.  

17. Wang, H., H. Feng, and Y. Luo. 2004. Microbial reduction and storage quality of fresh-cut cilantro washed with acidic electrolyzed water and aqueous ozone. Food Res. Intl. 37:949-956.