Low-risk silage (category 3)

Low-risk silage is produced at gut- and refinement companies, and is produced of entrails, segments, and back and head of the fish/salmon, that is not sick. The silage is grinded in a grinding mill. After this formic acid is put in (about 3%), and the stirring continues until the silage becomes a liquid.
The pH levels are about 3,5 – 3,8.
There is no processing for this silage, but only collecting, store, and sale.

The silage is exported to feedstuff producers, among others to little pigs feed abroad, and the only condition is that the silage may not be used again in the fish food chain.

Production process:
(Flow card)                       Receipt                             Storehouse                      Shipping

Fish and the refuse of fish are products that decompose quickly, and must therefore not be preserved for a long time, unless other preventive initiatives are made. Silage is a good way to secure a fast and good storage stability. Furthermore the silage is an easy and safe product to transfer, because it is easy to pump.

To make silage it is necessary to have fish and/or entrails, acid, and the equipment to grind and mix it all together to a homogenous mass. Equipment must also be where the finished silage can be stored.
The refuse of the fish are ground at the same time as the acid is held in.
It is necessary to secure that there is enough acid, so that all the silage has the same pH value. This is among other things affected by how many bones are in the silage. Bones neutralize acid, and will therefore cause the pH levels to rise again after a certain period of time. If the pH level rises above a certain amount (pH 4,0 – 4,5 for formic acid) the silage will decompose. It is then necessary to put more acid in the silage.