Indalisation

Tindalization, or fractional heating method, is a type of thermal sterilization by heat devised by the British physicist John Tyndall (1820-1893).

How is tindalization performed?

Between three and five heats are carried out at 60-80 ° C lasting about one "hour each, separated by a rest of 24 hours at room temperature or, more correctly, in incubation conditions (30-35 ° C). .

The tindalization is based on the principle, however questionable, that the vegetative microbial forms would be destroyed by the first heating to 60-80 ° C; in the following 24 hours of rest the spore-forming forms, formed following the initial heat treatment, would evolve into a vegetative form and would then be destroyed by subsequent heating. However, this principle does not consider that the spores evolve to the vegetative form only in optimal conditions.
In any case, tindalization is advisable if the material to be sterilized is very sensitive to heat and has a low initial microbial load.