Int J Food Microbiol. 2003 Sep 15;86(3):231-7.
Department of Agricultural and Biological Engineering, Pennsylvania State
University, University Park, PA 16802, USA.
Electrolyzed oxidizing water is a relatively new concept that has been
utilized in agriculture, livestock management, medical sterilization, and food
sanitation. Electrolyzed oxidizing (EO) water generated by passing sodium
chloride solution through an EO water generator was used to treat alfalfa seeds
and sprouts inoculated with a five-strain cocktail of nalidixic acid resistant
Escherichia coli O157:H7.
EO water had a pH of 2.6, an oxidation-reduction potential of 1150 mV and
about 50 ppm free chlorine. The percentage reduction in bacterial load was
determined for reaction times of 2, 4, 8, 16, 32, and 64 min. Mechanical
agitation was done while treating the seeds at different time intervals to
increase the effectiveness of the treatment.
Since E. coli O157:H7 was released due to soaking during treatment, the
initial counts on seeds and sprouts were determined by soaking the contaminated
seeds/sprouts in 0.1% peptone water for a period equivalent to treatment time.
The samples were then pummeled in 0.1% peptone water and spread plated on
tryptic soy agar with 5 microg/ml of nalidixic acid (TSAN). Results showed that
there were reductions between 38.2% and 97.1% (0.22-1.56 log(10) CFU/g) in the
bacterial load of treated seeds.
The reductions for sprouts were between 91.1% and 99.8% (1.05-2.72 log(10)
CFU/g). An increase in treatment time increased the percentage reduction of E.
coli O157:H7. However, germination of the treated seeds reduced from 92% to 49%
as amperage to make EO water and soaking time increased. EO water did not cause
any visible damage to the sprouts.