Endospores can withstand high temperatures due to their unique composition. The outer layer of the endospore, known as the exosporium, provides protection against harsh conditions. The core of the endospore contains the dehydrated cell and a high concentration of dipicolinic acid, which contributes to its heat resistance.
While boiling water can kill most vegetative bacteria (the actively growing and dividing form of bacteria) at 100 degrees Celsius, it may not be sufficient to kill endospores. These spores can survive boiling temperatures for extended periods, ranging from a few minutes to several hours. In some cases, endospores may even survive for years in boiling water.
To effectively kill endospores, higher temperatures and/or longer exposure times are required. Steam under pressure in an autoclave, which achieves temperatures above 121 degrees Celsius (250 degrees Fahrenheit) and pressurization to increase the penetration of steam, is commonly used to ensure the destruction of endospores. This sterilization method is essential in various industries, including food, pharmaceutical, and medical settings.
It's important to note that boiling water at 100 degrees Celsius is still a crucial step in food preparation and sanitation, as it can kill many harmful bacteria and vegetative cells. However, it should not be solely relied upon for the elimination of endospores, especially in cases where complete sterilization is required. Additional measures, such as pressure cooking or autoclaving, may be necessary to ensure the destruction of these resilient structures.