A soiled silo before cleaning

Clean and Safe

Steinbeis experts curb dangers posed to humans thanks to an innovative silo cleaning system

Social prosperity and reliable supplies for the population require sophisticated and developed methods of agricultural production. Food and animal feeds supplied by agricultural producers are stored in silos before entering further processing or going into intermediate and final storage. This makes silos an indispensable if not crucial link in the supply chain. At the same time, however, it also makes silos an Achilles’ heel in the value chain. The Steinbeis Innovation Center for Applied Product and Process Development (IPP) has been turning the spotlight on automated silo cleaning.

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To bacteria, fungal spores, mites, and other pests, the inside of a silo is like the land of milk and honey. It’s dark, nice and warm, there’s plenty of condensation, and it’s quick and easy to find a whole variety of nutrients. In a nutshell, these are ideal living conditions for undesirable silo inhabitants. It’s very easy for germs to multiply rapidly in contaminated silos, thus rendering entire harvests unusable.

A common method for dealing with animal feeds contaminated with bacteria is to treat everything with antibiotics. The consequences of this approach are already well known. Many problems of our times stem from this practice, ranging from antibiotic residues in wastewater to contaminated groundwater and the development of multi-resistant germs, which have been claiming more and more lives in recent years. Another invisible hazard is mycotoxin in animal feeds. These first attracted attention when livestock became increasingly susceptible to infections, developed behavioral problems, started refusing food, and began vomiting. There was also a rise in the number of underdeveloped calves and, ultimately, deficiencies in milk and meat quality. Improperly managed silos can thus quickly lead to economic problems for farms. In addition to health risks, they also pose considerable financial risks. It is also worth remembering the increasing importance of sustainable agriculture.

Regular silo cleaning prevents germ contamination

To avoid risks to product safety caused by grains or feed becoming contaminated with germs or mold, it is essential that storage silos are regularly cleaned and thoroughly disinfected. The idea is to keep germs at permanently low levels inside the silo. Under EU hygiene legislation, any business that handles food is responsible for food safety and must comply with regulations and secure product safety. This is stipulated by regulations governing food hygiene and salmonella, as well as Regulation (EC) 183/2005, which lays down requirements governing feed hygiene. The latter regulation covers all activities of animal feed companies, spanning all stages of the feed chain, including primary production and the feeding of farm animals. However, it does not describe the methods or standards of implementation.

The insides of silos are danger zones for human beings. They’re dark and covered in thick dirt and dust. They’re not ventilated, they’re difficult to get in and out of, and they’re full of toxic gases and unavoidable aerosols. Not only does this make silo cleaning time-consuming, it can also be life-threatening. Current forms of technology make it possible to clean silos by taking systems into vessels and cleaning them manually, subject to extensive safety standards.

In the past, many serious and sometimes fatal accidents have occurred after entering into silos, and despite prevailing occupational safety regulations, even today silo cleaning is considered a dangerous and disliked grind that only certified companies are permitted to perform. Using hoisting ropes, scaffolding on the inside of the silo, industrial climbing systems, and a mobile carrier or pulpit, the inner surfaces of the silo can be cleaned by sweepers that agitate and redistribute dirt and grime. Respiratory exposure to the bacteria and mold spores contained in the dust generated by this process poses a major health risk and often the results of cleaning are unsatisfactory. The results are similar when tank spray heads are used. These are suspended into the silo and lowered in a tumbling and swinging motion in order to clean the surfaces. Some areas are missed during cleaning, however, and a lot is down to guesswork.

Quality assurance: challenges and solutions

Generally, there is no evidence that cleaning has actually worked. This is a weakness in the otherwise advanced quality systems of production chains, which are extensively documented and monitored, and as a result, this compromises elaborately planned and expensive quality standards. This state of affairs and the factors that drive it are part of a complex web of socio-political, procedural, and economic challenges, which the Steinbeis experts in Freiberg define as follows:

  • Food standards and feed quality are crucial for the well-being of humans and animals
  • Grain and animal feed standards must be adhered to
  • The ultimate priority is commercial viability and consumer protection
  • Regular and thorough silo cleaning is an imperative
  • Manual silo cleaning methods are costly, dangerous, and deliver poor results
  • Tighter quality requirements and declining margins demand solutions that achieve automated, safe, and comprehensive silo cleaning, underscored by evidence that cleaning is effective

The essential and most promising solution to these problems is to develop meticulous silo cleaning robots and introduce standardized quality control systems. The development of such systems is now receiving intense support thanks to the expertise offered by the Steinbeis Network. Founded in September 2022, the Steinbeis Innovation Center for Applied Product and Process Development (IPP) deals with tasks and issues relating to automated silo cleaning, also looking at its impacts. This includes topics such as the long-term operation of robot technology and microbial growth in silos over time. The focus at the Steinbeis Transfer Center for Mechanical and Plant Engineering (TMA) lies in the transfer of developments into practice and the dissemination of innovative and thorough cleaning technology developed by the inventor Bernd Pragst.


Dr.-Ing. Kristin Mandel (author)
Steinbeis Entrepreneur
Steinbeis Innovation Center Applied Product and Process Development (IPP) (Freiberg)
Steinbeis Transfer Center Mechanical and Plant Engineering (TMA) (Freiberg)

Ronny Wagler (author)
Steinbeis Entrepreneur
Steinbeis Innovation Center Applied Product and Process Development (IPP) (Freiberg)
Steinbeis Transfer Center Mechanical and Plant Engineering (TMA) (Freiberg)

Bernd Pragst (author)
Managing Director
Silo Service Bernd Pragst (Friedland)