Fish Microbiology and Quality Assurance (2+2)

Unit 4 - Food preservation techniques and microorganisms

4.6.3. Resistance of spores

Bacterial endospores are highly hardy structures capable of withstanding extreme heat, drying, freezing, radiation and chemicals that would readily kill vegetative cells. Ability to survive such harsh environmental conditions is attributed to several factors.

• The high heat resistance of spores is due to high content of calcium and dipicolinic acid which removes water and makes it dehydrated. The absence of free water offers heat resistance and thus protective effect on proteins and nucleic acids.
• The spore is metabolically inactive due to non availability of water which makes it resistant to further drying.
• Presence of thick and impervious cortex and spore wall offer resistance against radiation and chemical substances.