Which control method is most effective for killing bacteria and spores?

Radiation is the most effective control method for killing bacteria and spores due to its ability to disrupt the cellular structures and genetic material of microorganisms. It works by ionizing the molecules within the cells, which leads to the formation of free radicals and subsequent damage to DNA, proteins, and other critical cellular components. This disruption can effectively eliminate both vegetative bacteria and resistant spores, making radiation a powerful tool in sterilization processes, particularly in medical devices and food safety.

Desiccation involves removing water to inhibit microbial growth, but it is not reliably lethal to all bacteria and spores, as many can survive in a dormant state. Cold storage slows down the metabolic processes of microorganisms but does not always kill them; instead, it can merely extend their survival. Filtration is effective for removing bacteria from liquids and air but does not kill the organisms, so they can potentially regrow if conditions become favorable again. Thus, among the options provided, radiation stands out as the most potent method for achieving complete sterilization against both bacteria and spores.