Synthesizing Inactivation Efficacy of Treatments against Bacillus cereus through Systematic Review and Meta-Analysis and Evaluating Inactivation Efficacy of Commercial Cleaning Products against B. cereus Biofilms and Spores Using Standardized Methods
Jayne E. Stratton
Date of this Version
Bacillus cereus is ubiquitous and can be easily carried in food processing facilities. It is problematic because it can survive various treatments such as heat, radiation, and chemical cleaning by forming spores and biofilms. Some review papers have discussed inactivation efficacies of different treatments against B. cereus, but they are narrative without quantitative summaries. This study first aimed to find effective and food industry-applicable treatment candidates against B. cereus spores and biofilms by synthesizing and comparing the efficacy of treatments using systematic review and meta-analysis. After screening, 17 studies were included, but only nine studies were used for meta-analysis due to the absence of statistical data. Oxidizing agents presented the best efficacy with an average of 2.51 log10 inactivation. For inactivating B. cereus biofilms, Clean-In-Place (CIP) procedures with acid or alkaline detergents generally demonstrated good efficacy ranging from 0-6 log10 inactivation. However, not all treatments and conditions being tested were applicable in the food processing environment. Also, diverse methods were used for measuring inactivation efficacy which made a direct comparison of treatments unavailable. To deal with these issues, studies were conducted to evaluate the sporicidal and anti-biofilm efficacy of commercially available cleaning products in food industry-applicable conditions with standardized methods. For the sporicidal efficacy, four commercially available cleaning products were tested. A sanitizer with an Environmental Protection Agency (EPA) biofilm claim, Synergex™, showed the best efficacy with over 5.33 log10 reduction in 5 min at 2% concentration. Less efficacy was shown at 1% concentration with a 0.5-2.8 log10 reduction. A sanitizer with an EPA sterilant claim, P3-oxonia™ at 2.5% concentration, showed about 1-log10 reduction in 10 minutes, and at 5% concentration showed 1 to 5 log10 reduction. An alkaline detergent Lift™ III and an acidic detergent HD PL-10™ showed log10 inactivation. For the anti-biofilm efficacy, three commercial cleaning products were tested. Synergex™ showed over 5-log10 reductions in every condition tested. HD PL-10™ showed 0-2.1 log10 reduction with better efficacy when application time, concentration, and temperature increased. Lift™ III showed a 0.3-1.7 log10 reduction in tested conditions.
Advisor: Jayne E. Stratton & Andréia Bianchini-Huebner