An innovative way to decontaminate

by Dieter Otto Gräf
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The globalization of world markets, an expanding Europe, and greater health consciousness have resulted in new food consumption habits around the world. The demand for “healthier” and “more hygienic” food requires an increasingly faster modification of production processes.

Today, customers not only ask for more food indulgence but also for greater hygiene. Manufacturers are under pressure to understand and respond to this trend in order to defend market share and stay ahead of the competition.

The production of marketable foodstuff from raw materials of vegetable, animal and mineral origin is subject to complex local, regional, national and international government rules and regulations for food production and sale, including food quality and food safety.

When looking at the production of quality flours, from grain in particular, buyers today insist on food with the lowest amount of bacteria, yeast and mold possible. However, modern food production cannot be managed with the help of sophisticated technologies only.


Food contamination is often caused by substances brought from external sources into the production process. Grain contamination can occur mainly in the following areas:

• Field microorganisms, depending on: the region, in which the grain grows; grain variety; harvest weather; use of fertilizers; and crop rotation.

• Grain storage microorganisms, depending on: flat-bottom bin, open/closed; closed silo space (bins); drying; and ventilation and aspiration.

• Transportation microorganisms, depending on cleanliness of the means of transportation: truck, open, closed; rail; ship; and grain delivery through a farmer (fertilizer and manure residues).

• Processing facility microorganisms, depending on: reception and cleaning equipment; grain silo concept; weather conditions, grain preparation; cleaning machinery, transport elements; tempering water quality; type of tempering; and temper bin design.

• Tempering time microorganisms, depending on: treated dampening water and temper times.

• Milling microorganisms, depending on: diagram design; piping layout; and machine design. 

• End-product silo microorganisms, depending on: aspiration; silo wall design; and fulfillment of HACCP regulations.

• Bagging and bulk loading microorganisms, depending on: weather conditions; design; packaging material; and means of transportation.

Studies have shown that a different flora contamination occurs in almost every flour mill. However, up to now, no effective method or process has been found to reduce total bacteria count to a minimum.

Above all, it is the time spent in the temper bin after conditioning that has a large influence on grain contamination. As the tempering time increases, the grain temperature rises by 2 to 4 degrees C (36 to 39 degrees F) due to biological, chemical and mechanical actions in and around the grain kernel. Water, tempering time and the initial grain temperature create a medium, which increases total bacteria count.

Since a large part of the contamination can be found on the grain surface due to field, storage and transportation flora, many studies show that high total bacteria count values can be reduced with mechanical processing. However, the grain surface also consists of the crease, which takes up to one-sixth of the grain surface.

This is another reason for the contamination of final flour and bran products with mycotoxins, mold, yeast and total bacteria count.


Mechanical processing, such as hulling, brushing, peeling, impacting and detaching, cannot remove the contamination in the deepest point of the crease in a cereal kernel. One or more processing steps, such as with wet-peeling, could considerably lower the value of contamination but never reduce it to zero.

Lowest tempering times are therefore the first and foremost prerequisite for more hygienic end products. One effective solution to reducing tempering time is the dampening of grain with the help of the patented vibronet process. Here, the natural molecular structure of the water particle is broken down with very high vibration energy. The dampening water looses its surface tension and forms a water film. This film can then surround the entire kernel and penetrate fast and equally through the entire surface of the outer layer into the endosperm. The technology thus allows the tempering water to enter into the crease.

The dampening water, being a complex network of molecules, can be used as a carrier to distribute bacteria reducing agents over the entire grain surface. For many years, attempts were made to achieve a reduction of the bacteria count using certain agents. However, food regulations today are so strict that certain additives, such as chlorine, are prohibited.

However, there is an alternative that became known due to research in outer space: activated water. To treat water on the MIR space station, the Russians and the Swiss have a patent which produces drinking water for human consumption from waste and condensation water.

Activated water is produced with the help of the diaphragm-electrolysis process. The electro-chemical activation of water generates two highly active metastable disinfection cleaning solutions. Their source substances are water and salt (one to four grams per liter), and they are decomposed into water and salt again.

As a disinfection fluid, activated water has distinctive microcidal, bactericidal, virocidal and fungicidal properties. Laboratory reports show that all germs – even spores – are eliminated within a few minutes.

Activated water also prevents resistance development of germs. It is not toxic and therefore suitable to reduce yeasts, mold and total bacteria count, and it stops the growth of the mycotoxins, DON and ZEA values in food-related raw materials.

Test results from mill operations where activated water was added to the tempering water with the help of vibronet technology show that it is possible to guarantee the necessary hygiene requirements for today’s food products using the new vibroDes decontamination method.

The combination of two systems – the vibronet dampening and the Aquis water purification procedure — makes a drastic reduction of total bacteria count, mold and yeast possible: If used individually, though, the desired total bacteria count reduction is not achieved.

The dampening technology allows the dampening water mixed with activated water to penetrate equally into the hull throughout the entire kernel surface, including the crease. The activated water can thus eliminate the fusarium contamination not only on the outer surface and in the upper hull layers, but also in the crease of the cereal kernel as well.

Since the technology also reduces the tempering time to a minimum, all prerequisites and conditions are met to reduce total bacteria count to an absolute minimum. As a result, both end products (flour and bran) receive an added benefit for sales purposes: guaranteed product quality and security due to reduction of total bacteria count, yeast and mold.

Healthy and hygienic foodstuff is the key issue facing the food industry today. As consumers are more conscious of the importance of healthy and hygienic food, processors of flour and bran must adapt to new standards for the milling process.

Maximum values, which must not be exceeded, have been set for total bacteria count, yeast and mold as well as mycotoxins and their waste products, the endotoxins.

In order to guarantee these values, the patented vibronet dampening process is used together with the Aquis decontamination process with great success.

Shortest tempering times combined with the decontamination process – the vibroDes method – guarantee reduced bacteria and set a new milestone for more healthy and hygienic food.

Dieter Otto Gräf is technical director for Lahnau, Germany-based vibronet. He can be reached at