Inspissation is the process of increasing theviscosity of afluid, or even of causing it to solidify, typically bydehydration or otherwise reducing its content ofsolvents. The term also has been applied to coagulation by heating of some substances such asalbumens, or cooling some such as solutions ofgelatin oragar. Some forms of inspissation may be reversed by re-introducing solvent, such as by adding water tomolasses orgum arabic; in other forms, its resistance to flow may include cross-linking or mutual adhesion of its component particles or molecules, in ways that prevent their dissolving again, such as in the irreversible setting orgelling of some kinds ofrubberlatex, egg-white,adhesives, orcoagulation of blood.[1]
Inspissation is the process used when heating high-protein containing media; for example to enable recovery ofbacteria for testing. Once inspissation has occurred, any stained bacteria, such asMycobacteria, can then be isolated.
Aserum inspissation orfractional sterilization is a process of heating an article on 3 successive days as follows:
| Day | Temperature | Time | Purpose |
|---|---|---|---|
| 1 | 85 °C | 60 minutes | Drying of the medium and killing the organisms in their vegetative form |
| Time in between | Overnight incubation | Growth of vegetative forms from spores | |
| 2 | 75 to 80 °C | 20 minutes | Killing the organisms in their vegetative form |
| Time in between | Overnight incubation | Growth of vegetative forms from any spores remaining | |
| 3 | 75 to 85 °C | 20 minutes | Killing the organisms in their vegetative form as well as the leftover spores |
Incystic fibrosis, inspissation of secretions in the respiratory[2] and gastrointestinal tracts is a major mechanism causing the disease.