B. subtilis ATCC 8473 spores were obtained by the method
of Katina et al. (2002) with some modifications. Cells from a 6-
day-old culture on SA at 30 °C were collected, suspended in
50 mM phosphate buffer (pH 7.0), subjected to heating at 90 °C
for 20 min in a water bath, and rapidly cooled to room
temperature with ice. Spores were recovered by centrifugation
at 7000 ×g for 20 min at 20 °C, suspended in the buffer and
plated on SA. Plates were grown for 6 days at 30 °C. Cells from
this culture were collected and processed as reported above, and
spores were counted in a Thoma chamber (Brand, Blaubrand,
Germany). One ml of the spore suspension corresponding to
about 106 spores/ml was used in bread-making tests.