Mushroom Farming & Processing | Ask The Expert

We've been foraging, growing and eating mushrooms for thousands of years, but how has that changed in the 21st century?

I interviewed Jan Klerken, founder of Scelta Mushrooms, to understand the different ways of eating, processing and growing mushrooms. 

How did you get into the mushroom farming industry?

My love for mushroom farming comes to me quite naturally. My parents owned a small mushroom farm and canning factory. As a six-year-old, I saw the little white miracles and thought to myself, ‘This is my life!’. My parents’ company was sold in 1988, but watching them work with mushrooms inspired me to start my own business five years later.

What kind of mushrooms do you work with? Are some varieties of mushrooms easier to grow and process than others? 

We work only with white button mushrooms because they are well-known around the world and we can grow them year-round. Other mushrooms like shiitake or oysters are difficult to scale up. Around 40% of the mushroom farming business worldwide is in white button mushrooms.

How do you grow your white button mushrooms on your mushroom farm?

Our mushrooms grow on horse manure substrates, and we hope to be the first company to grow mushrooms fortified with vitamin B12. This will help consumers who wish to eat less meat because currently, animal-based foods are the main source of B12 in our diets. We already produce mushrooms enriched with vitamin D. 

How do you enrich the mushrooms with vitamin D?

This is done during processing by pulsing UV light onto the mushrooms. Mushrooms contain a provitamin called ergosterol which can be converted into vitamin D under the influence of UV light. This makes mushrooms the only non-animal, non-synthetic source of vitamin D. So, the treatment we give the mushrooms is only to activate the vitamin D. 

A lot of environmentally conscious consumers are trying to reduce the amount of animal-based foods they consume. Do you think mushrooms could play a role in making this transition a smooth one?

Yes, of course! We already have a lot of demand for vegetarian burger patties. Blended patties are also a popular option where half the meat content is replaced with mushrooms. Another option is to use mushrooms as a topping in burgers, which makes the patty smaller and uses less amount of meat per burger. 

We also work with local sports centres in the Netherlands where athletes want to maintain a high-protein diet without consuming too much meat. 

Food waste is also a hot topic in the food industry right now. Is there some waste produced while harvesting or processing mushrooms? Can this be used in any way?

Food waste is a critical issue, and we try to make the best possible use of the entire mushroom. When mushrooms are harvested, 10 to 20% of the stem is thrown away because it has a lot of soil on it. We collect these stems from growers, clean them, and turn them into a thick, paste-like reduction. We sell this (very flavourful) product to the food processing industry, and they make snacks out of it. 

Mushrooms are packed with a flavour known as umami. This concentrate therefore has high amounts of umami flavour in it and can be used to reduce the amount of salt or sugar it takes to make a product taste good. The possibilities are endless!

What are some other ways of consuming or processing mushrooms? 

A lot of mushrooms that are used in catering are actually preserved mushrooms that look and taste just like fresh mushrooms. In the past, canned mushrooms were really big, but we realised the new generation is not a fan of this product. So, we had to think of ways in which preserved mushrooms could be introduced in a more appealing and innovative format.

Today, frozen mushrooms are our largest business. We also process them using the sous vide cooking style, wherein the mushrooms are cooked for a long time, at a low temperature. This results in preserved mushrooms that do not require any additives or even refrigeration. We also process mushrooms by dehydrating them using an air dryer.

Does this kind of processing affect the mushroom’s flavour or nutrition?

Any food ingredient that is cooked or processed will be altered in taste and nutrition. The same goes for mushrooms. Sustainability, health, and taste are key drivers for us when it comes to product innovation. For instance, breaded and fried mushroom snacks taste different from mushrooms that have been grilled and then frozen. The goal is, of course, to keep the flavours as close to fresh mushrooms as possible. 

Sometimes, preserved mushrooms can be fresher than unprocessed mushrooms in the market. This is because we process the mushrooms within 24 hours of being harvested, whereas unprocessed mushrooms you buy in the market could be well over two weeks old!