Spore forming bacteria vary in their susceptibility to chemical
disinfectants. In former studies the resistance of spores of different
Bacillus spp. and Clostridium spp. were compared and B. cereus
proved to be the most resistant spore former (Blakistone et al.,
1999). Suspension and carrier tests are able to detect differences
in resistance of spores against disinfectants (Andre et al., 2011). The
susceptibility of strains used in this study greatly varied and are
comparable to studies with a different test model (Sudhaus et al.,
2012). Spores of DSM 4384 were most susceptible to PES 15/23
and with concentrations of 0.5%e1.5% efficacy of disinfection
against spores was detected regardless of the temperature (Tables 4
and 5). DSM 318 strain was more resistant than DSM 4384 and if
disinfection was done at lower temperatures (10 C) and with
protein, concentrations of 2.0% and treatment of 60 min could not
guarantee efficient reductions of spores (Table 5). These conditions
(10 C; 2.0%; 60min; with protein) led to reductions higher than the
detection limit (3.56e3.99 log CFU/ml) but to positive results in the
qualitative suspension test (Table 1)