Effectiveness of a peracetic acid-based disinfectant against spores of Bacillus cereus under different environmental conditions

•Concentration of disinfectant and temperature influences efficacy of disinfectant.•Time of exposure and bacterial strain also influences disinfection efficacy.•Sterile bovine serum had no significant influence on reductions.•Spores of Bacillus cereus vary in their susceptibility against the disinfectant.

A peracetic acid based disinfectant was tested for its efficacy against spores of different Bacillus cereus -strains (DSM 318, 4312, 4313 and 4384). To determine the influence of different factors like exposure-time, temperature and presence of protein quantitative and qualitative suspension tests were performed. Spore suspensions of B. cereus were treated with various concentrations of a representative peracetic acid based disinfectant at three temperatures (10, 15 and 20 °C), with protein load and with different exposure times (5, 30 and 60 min). Temperature, level of concentration and exposure-time had a significant influence on reduction of spores of B. cereus (p < 0.05). The susceptibility of spores of different strains greatly differed. A treatment of spores of DSM 4384 with 2.0% for 30 min even at 10 °C inactivated all present spores (initial number 6.18-6.71 log CFU/ml). Spores of B. cereus strain DSM 4313 had only reductions of 0.16-0.97 log CFU/ml at same treatment conditions. The presence of inactivated bovine serum as interfering substance had no significant influence on reduction (p > 0.05).