Clostridium sporogenes forms highly heat resistant endospores, enabling this bacterium to survive
adverse conditions. Subsequently, spores may germinate, giving rise to vegetative cells that multiply and
lead to food spoilage. Electron microscopy was used to visualise changes in spore structures during
germination, emergence and outgrowth. C. sporogenes spores were surrounded by an exosporium that
was oval in shape and typically 3 mm in length. An aperture of 0.3e0.4 mm was observed at one end of the
exosporium. The rupture of the spore coats occurs adjacent to the opening in the exosporium. The
germinated cell emerges through this hole in the spore coat and then through the pre-existing aperture
in the exosporium, before eventually being released, leaving behind a largely intact exosporium with an
enlarged aperture (0.7e1.0 mm) and coat shell. The formation of this aperture, its function and its
alignment with the spore coat is discussed.
© 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license