Gaseous ozone exposure significantly reduced ST, total
aerobic and anaerobic bacterial counts at each time point
compared with the nontreatment groups. The reduction
patterns of these three counts were similar for 3 days, and
the difference in reduction in bacterial count between the
ozone treatment groups and the nontreatment groups was
gradually increased over time. This pattern suggested that
the effect of gaseous ozone increased with an increase in
storage time. Similar findings have been reported by
Cardenas et al. (2011), who found that an ozone concentration
of 154 × 10−6 kg O3/m3 decreased the total aerobic bacteria
by less than 1.0 log10 during the first 4 h of treatment,
with a greater reduction, ranging from 1.0 to 2.0 log cfu/g,
found after 24 h of exposure. An ozone concentration of
270 × 10−6 kg O3/m3 was effective at inhibiting bacteria
found naturally in fish, such as Pseudomonas putida, Lactobacillus
plantarum and Enterobacter spp. (Da Silva et al.
1998). The concentration of ozone in our study was quite
low (10 × 10−6 kg O3/m3) compared with other studies,
which reported values of 154 × 10−6 kg O3/m3 (Cardenas
et al. 2011) and 270 × 10−6 kg O3/m3 (Da Silva et al. 1998).