Safe storage units for safe feed- the inner coating can be a risk!

Thursday, June 27, 2019

In the last months, there was an incident involving high levels of PCBs in poultry feed. The source of the incident was traced back to contamination of chipped paint from the inner coating of the silo with the feed. In light of this incident, we would like to share some tips on maintaining tanks and silos used for storing feed.

Prevent that the coating becomes a risk

Coatings play an important role in protecting a silo or a tank against corrosion and abrasion. However, over time coatings are bound to deteriorate, presenting possible contamination concerns. Age, chemical exposure, frequent wash downs, general wear and tear are some factors cause this deterioration.

Maintenance plan

Creating a maintenance plan for areas and equipment that can have an effect on feed safety is a GMP+ requirement. Including silos and tanks in the maintenance plan can be a way to ensure that they are checked for wear and tear on a regular basis and the required repairs take place in time.

Ask support from trained professionals

Requesting the assistance of trained professionals in evaluating the condition of current silos and tanks can help identify the optimal maintenance plans. These service providers can also help the facility to develop repair specifications and expedite repairs to prevent feed safety issues.


If the need to expand or move a silo can be foreseen, consider opting for factory-applied coatings because they ensure that the silos are more mobile and expandable since each panel is individually coated. Coatings applied in the field are painted on the entire surface and therefore will tear or break when the silo is moved.

In case an old silo or a tank is being recycled, it is advisable to have the silo and its coating evaluated for safety, flow, and corrosion resistance. Incorrect maintenance of storage units can result in not only feed safety issues but also clogs and other operational problems.

Quality and Costs

It is important to consider that high-quality coatings may have a higher up-front cost but often last longer and reduce maintenance and recoating requirements. It is beneficial to select manufacturers who are well versed with requirements specific to the food and/or feed industry. Ensuring that the manufacturer has a recognized quality certification and adequate quality-control measures is important.

Overall, identifying areas of potential coating deficiencies, implementing preventive control plans, and committing to making repairs are the most effective ways to deal with this issue. We hope that these tips will help GMP+ participants prevent and minimize the occurrence of contamination incidents in the future.

Focus on this hazard

GMP+ international urges participants to include the hazards arising from the inner coating of silos and other storage units in their HACCP analyses. Factors such as the age of the silo, previous maintenance, and quality of the material could be taken into account.

GMP+ International will also be communicating with its Certification Bodies to take this hazard into consideration while conducting GMP+ audits.


Food Safety Magazine. Top 10 Areas of Coating Concerns in Food and Beverage Facilities.
Powder and bulk Engineering. How do I choose an appropriate interior finish when selecting a storage vessel?  

Powder & Bulk Solids. Tank and Silo Coatings: Nonabrasive, Noncorrosive, Longer Life Span.