Dry heat sterilization modelling for spacecraft applications

Abstract

Aims: Inactivation processes using heat are widely used for disinfection and sterilization. Dry heat sterilization of spacecraft equipment has been the preferred microbial inactivation method as part of interplanetary travel protection strategies. An antimicrobial model, based on temperature and exposure time based on experimental data, was developed to provide reliable sterilization processes to be used for interplanetary applications.Methods and Results: Bacillus atrophaeus spores, traditionally used to challenge dry heat sterilization processes, were tested over a range of temperatures in comparison with spores of Bacillus canaveralius that have been shown to have a higher heat resistance profile. D-value and Z-values were determined and used to develop a mathematical model for parametric sterilization applications. The impact of the presence of a contaminating soil, representative of Mars dust, was also tested to verify the practical application of the model to reduce the risk of microbial contamination in such environments. Conclusion:The sterilization model developed can be used as an intrinsic part of risk reduction strategies for interplanetary protection.Significance and Impact: Forward and backward planetary protection strategies to reduce the risks of microbial contamination during interplanetary exploration and research is an important consideration. The development of a modern sterilization model, with consideration of microorganisms identified with higher levels of heat resistance than traditionally deployed in terrestrial applications, allows for the consideration of optimal inactivation processes to define minimum criteria for engineering design. The ability to inactivate living microorganisms, as well as to degrade biomolecules, provides a reliable method to reduce the risk of known and potentially unknown contaminants in future applications.

Obtaining and Evaluating Growth Parameters of Spore Bacillus Atrophaeus Atcc 9372 Using Orange Waste as a Sustainable Crop Medium

“…The statistical study based on a 2 2 -point star-shaped factorial experimental design 2 2 model presented the linear correlation: Spores = {-1.15 + 0.0303 * [bagasse (g)] -0.00611 * [volume (ml)] + 0.611 * [time (d)]}, p = 0.000, R 2 = 0.452, with time (p = 0.000) being the most influential factor in spore growth and maturation. with the decimal reduction values ranging from: D E8 = 0.92 min to D E6 = 2.71 min and from D E12 = 1.34 min to D E4 = 3.98 min after 3d and 6d of cultivation at 102 °C, similar to data found in literature (SELLA et al, 2014b;FLAX, B. et al, 2022).…”

Effects of temperature, humidity, light, and soil on drug stability in hair: a preliminary study for estimating personal profiles using micro-segmental analysis of corpse hair

“…The dish was covered with a lid and stored in the dark at approximately 22 °C for 2 months. To prepare sterilized soil, the sieved natural soil was exposed to dry heat at 200 °C for 1 h [ 22 ].…”