Modeling of sporicidal effect of hydrogen peroxide in the sterilization of low density polyethylene film inoculated with Bacillus subtilis spores

Abstract

a b s t r a c tThe sporicidal effect of hydrogen peroxide (H 2 O 2 ) in the sterilization of low density polyethylene film (LDPE) was evaluated using a Central Composite Design (CCD). The effects of contact time (5-19s), bath temperature (23e70 C) and concentration of H 2 O 2 (0e35%) in an immersion bath were investigated.A 16 cm 2 film surface was evenly inoculated with 100 mL of the test microorganism Bacillus subtilis var.globigii ATCC9372 spores. The effective H 2 O 2 sporicidal activity was demonstrated at concentrations from 18 to 35% and in a temperature range from 46 to 70 C, resulting in 2e7 decimal reductions of B. subtilis spores. A quadratic mathematical model representative of the action of H 2 O 2 on the B. subtilis spores was developed as a function of concentration, time and temperature. Test specimens sanitized with 28% H 2 O 2 at 60 C for 8 s showed 4 decimal reductions. In the same sterilization procedure, but extending the time to 16 s, this value increased to 7 decimal reductions, demonstrating the efficiency of H 2 O 2 as a function of contact time. The sterilization system tested showed satisfactory performance in the sterilization of LDPE films, being capable of reaching up to 7 decimal reductions of the bacterial spore population.

Disinfectant wipes transfer Clostridioides difficile spores from contaminated surfaces to uncontaminated surfaces during the disinfection process

“…It is possible that the higher alcohol content of QA1 (55%) compared to 22.5% for QA2 and 14.3% for QA3 made it more sporicidal (Table 1 ). This could be further supported as the spore load on QA1 wipes after use were similar to those of products with active ingredient classes that are generally sporicidal in nature (HP1 and HP2) [ 36 ]. There were no statistically significant differences among the cross-contamination risk of HP products and SH.…”

“…This suggest that although these products did not carry sporicidal claims, the products exhibited significant sporicidal action. This could be explained by the fact that hydrogen peroxides are generally a class of active ingredients used for sterilization purposes [ 36 ] owing to their ability to inactivate spores.…”

Disinfectant Wipes Transfer Clostridioides difficile Spores from Contaminated Surfaces to Uncontaminated Surfaces during the Disinfection Process

“…It is possible that the higher alcohol content of QA1 (55%) compared to 22.5% for QA2 and 14.3% for QA3 made it more sporicidal [ Table 1]. This could be further supported as the spore load on QA1 wipes after use were similar to those of products with active ingredient classes that are generally sporicidal in nature (HP1 and HP2) [34]. There were no statistically signi cant differences among the cross-contamination risk of HP products and SH.…”

“…This suggest that although these products did not carry sporicidal claims, the products exhibited signi cant sporicidal action. This could be explained by the fact that hydrogen peroxides are generally a class of active ingredients used for sterilization purposes [34] owing to their ability to inactivate spores.…”

Added value of experts' knowledge to improve a quantitative microbial exposure assessment model — Application to aseptic-UHT food products

“…The D-values of mesophilic B. cereus were extracted from Membré et al (2006), converted into D-values at 121.1°C (using a z-value of 9.5°C (given by the expert)) and implemented as a Pert distribution, after logarithm transformation: log 10 (D 121.1 As the re-parametrization was not straightforward, to verify that there was no error, the mean, standard deviation, 2.5 th and 97.5 th percentiles obtained in @RISK were compared to values given by Rigaux et al (2013b). The log reduction number (in log 10 ) for the inactivation model associated with the sterilization of the packaging, came from Cardoso et al (2011): LR ste k~U niform(2; 7) (log 10 ). The logarithm of the bacterial spore air load was described by a Normal distribution (Den Aantrekker et al, 2003a): Normal(μ = 2.24; σ = 1.38) (log 10 cfu/m 3 ).…”