Application Areas

Microorganisms pose a significant economic threat that can lead to total write-offs of expensive raw materials.



High microbial content in foods and health care products represents a serious risk to human health — and is simply no longer admissible in today’s spirit of health-conscious diets and an absolutely safe food supply. In addition to these self-evident concerns, microorganisms pose a significant economic threat that can lead to total write-offs of expensive raw materials.

Germ reduction is therefore understandably a crucial preoccupation. The most common methods involve thermal processing, e.g. pasteurization. Gas, radiation and chemicals offer effective alternatives, yet all known methods come at a price: degraded quality (denatured proteins, mineral and vitamin depletion, sensorial alterations) and/or heavy restrictions. There are innovative approaches to germ reduction out there that work with hydrostatic pressure up to several thousand bar, but the cost will still remain prohibitive for the foreseeable future.

Evonik’s sterilization method, on the other hand, builds on moderate pressures—up to 400 bar (approx. 5800 psi)—and is inspired by supercritical fluid extraction technology. Here, water activity, particle size, germ height and desired microbial reduction still remain vital considerations—as are the qualitative requirements and ultimate purpose of the goods to be treated. Here, spore content is a critical aspect because pressure-based sterilization only deals with vegetative microbes (bacteria, yeasts, fungi), but not spores. The latter have to be addressed with additional measures such as germ induction and pressure cycles. The advantage of Evonik’s method resides in the added bonus: Besides effectively sterilizing the treated substance, the process can also be adjusted to affect other characteristics requiring extractive measures—this in addition to being much gentler on your feedstock than with conventional methods.

The bottom line: A process that not only effectively deals with a problem, but also adds value by enabling you to obtain other extracts or to remove pollutants or to enhance the quality and marketability of your end-product.

The advantages of sterilization using supercritical fluid treatment with carbon dioxide:

  • Gentler process than conventional thermal methods

  • Can be combined with other extractive applications

  • Not restricted in use

  • No process-related solvent residue—inherent to CO2 extraction process and technology