There are various different methods for preserving mushrooms. Mushrooms are being preserved in order to extend their shelf life. Fresh mushrooms only keep for about five days after picking. Preserved mushrooms can be kept for a longer period of time (even up to five years!)
The preserving industry processes the fresh mushrooms in different ways. After mushrooms have been picked at the farm, they are transported to the processing factories as quick as possible. The mushrooms are immediately placed in a vacuum where they suck up a lot of water. Mushrooms contain quite a bit of air: by placing them into a vacuum this gets replaced by water, making sure they won’t float to the surface in the blanching kettle.
Blanching mushrooms (dunk them in almost boiling water) is the first step in prolonging the mushrooms’ shelf life. By heating them, the mushrooms are less susceptible to deterioration. The mushrooms find their way via a conveyor belt: a machine slices them, ice water cools them, they’re dried and at the end they roll from the belt into large plastic bags or buckets. It takes just half an hour to process 10 kilos of fresh mushrooms into a bag. When cooled, they keep for six weeks.
Next to our mushrooms in cans and polybags, they can be found in buckets.
As a final step, the mushrooms can be pasteurized or sterilized so they keep even for longer. Pasteurization means mushrooms are heated to 95 degrees Celsius for a while, extending the shelf life to about six months (as long as the mushrooms are kept refrigerated). In case of sterilization, mushrooms are heated to 125 degrees Celsius. Cans of sterilized mushrooms can be kept for a maximum of five years.
Preserving mushrooms in vinegar, oil or salt
Mushrooms can also be preserved in vinegar or oil. In Eastern Europe they mostly use vinegar, while preserving in oil is common in the Mediterranean. A well-known example are mushrooms eaten as an Italian antipasto or starter. In China, mushrooms are often preserved in salt. The distances to preserving factories in China are too large, which makes it impossible to process fresh mushrooms. A disadvantage of preserving in salt is that the mushrooms have to be rinsed in a large amount of water to prevent them from tasting too salty. This does not have a favourable effect on the flavour. That is one of the reasons why consumers around the world choose Dutch preserved mushrooms. Because the processing industry and the growers are located so close to another, mushrooms can be processed immediately after harvest. Therefore Dutch mushrooms retain their strong fresh mushroom flavour, whether packed in a can, jar, bag or bucket.
Would you like to take a view into a preserving factory? No problem.