Steam sterilisation

The steam sterilisation of powdery goods can be conveniently carried out in the amixon® apparatus. amixon® sterile reactors also serve as vacuum mixer dryers. They are used in particular for powdery goods. The bulk goods can be dry, moist or suspended. Sterilisation processes are usually carried out in batches. Sterilisation should take place quickly in order to avoid flavour changes. Water vapour has a high heat capacity and can heat the mix particles very quickly.

The batch sizes can vary greatly. There are reactors for batches of 100 litres. There are reactors that can sterilise 15 m³ and more.

Sterilisation/sterilisation is based on the denaturation of proteins, which occurs when microorganisms are exposed to elevated temperatures for a defined period of time. Almost all organic field and garden products such as spices, tea, cereals, fruit and vegetables are microbially contaminated to a greater or lesser extent.

In the European Union, Regulation (EC) No. 2073/2005 regulates the microbiological criteria for foodstuffs. This regulation sets specific limits for certain microorganisms in various food categories. This only applies indirectly to medicinal teas. The European Pharmacopoeia recommends microbiological guideline values for medicinal teas:

- Moulds: less than 10⁵ colony-forming units per gram (CFU/g) - E. coli: less than 10² CFU/g These recommendations are based on the assumption that boiling water is poured over the tea before consumption, which reduces the bacterial load.

The bulk material to be sterilised is placed in the amixon® mixing reactor. The double-walled system is then closed. A heat transfer medium circulates in the double jacket and heats the product. Water vapour is also introduced into the mixing reactor. The pressure increases as the temperature rises. The water vapour must not condense at any point in the mixer reactor.

After a defined reaction time, the water vapour is removed. The pressure drops. Applying a vacuum ensures fast and efficient drying. The temperature of the bulk material drops. It only rises again when the drying process is complete.