Removability of bacterial spores from solid surfaces during cleaning
Removability of bacterial spores from solid surfaces during cleaning
Removability of bacterial spores from solid surfaces during cleaning
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Removal pr<strong>of</strong>iles <strong>of</strong> the adherent <strong>spores</strong> <strong>during</strong> 30 min alkali <strong>cleaning</strong> were found to follow the first order<br />
kinetics approximately. The <strong>spores</strong> on PP coupon gave lower rate constant than those on SS coupon.<br />
Table 1. Residual fractions <strong>of</strong> B. subtilis <strong>spores</strong> on SS and PP coupons A after 10 min alkali treatment with agitation at<br />
25˚C or 75˚C in comparison with survival fractions <strong>of</strong> <strong>spores</strong> suspended for 10 min in alkali solution.<br />
NaOH (%)<br />
Temperature Residual fraction <strong>of</strong> adherent spore<br />
(°C) on SS on PP<br />
Survival fraction <strong>of</strong><br />
suspended spore<br />
0.2 25 0.79 ± 0.07 a 0.98 ± 0.03 a 0.45 ± 0.12 b<br />
0.2 75 0.63 ± 0.02 a 0.87 ± 0.23 a 0.17 ± 0.05 b<br />
1.0 25 0.01 ± 0.01 b 0.72 ± 0.07 a 0.01 ± 0.01 b<br />
1.0 75 ND 0.34 ± 0.01 ND<br />
ND: viable <strong>spores</strong> not detected. A Each coupon was contaminated with spore suspension and<br />
exposed to dry environment for 60 min prior to alkali treatment. a,b Values, expressed as mean ±<br />
standard deviation, in the same row followed by different superscript letters differ significantly<br />
(P
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