In recent years, numerous recalls of lettuce, leafy greens, sprouts and microgreens have been linked to these pathogens. In Canada, organic microgreens were recalled after E. coli was detected. In Ireland, spinach and mixed leaf products were withdrawn from the market due to Listeria monocytogenes. In the United Kingdom, a major E. coli outbreak linked to lettuce resulted in widespread product recalls, while in the United States a Listeria outbreak associated with packaged salads led to multiple fatalities.

You can read more about some of these incidents here:

• Food Safety News – Microgreens recalled in Canada because of E. coli: https://www.foodsafetynews.com/2026/05/microgreens-being-recalled-in-canada-because-of-e-coli/
• Food Safety Authority of Ireland – Recall of various branded spinach and mixed leaves: https://www.fsai.ie/news-and-alerts/food-alerts/recall-of-various-branded-spinach-and-mixed-leaves
• The Guardian – UK E. coli outbreak linked to lettuce: https://www.theguardian.com/world/2024/jun/20/number-hospitalised-by-e-coli-reaches-86-as-uk-lettuce-outbreak-grows
• U.S. Food and Drug Administration – Listeria outbreak linked to Dole packaged salads: https://www.fda.gov/food/outbreaks-foodborne-illness/outbreak-investigation-listeria-monocytogenes-dole-packaged-salad-december-2021

Clean Growing Media Is One of the Most Important Barriers Against Contamination

Foodborne outbreaks rarely have a single cause. Seeds, irrigation water, equipment, handling and the production environment can all contribute to contamination. However, one factor is often overlooked: the growing substrate itself.

Contaminated substrate can act as a reservoir for harmful microorganisms. In the production of lettuce, herbs and microgreens—where crops are harvested within weeks and consumed fresh—it is essential to minimise biological risks before the seeds are even sown.

For growers committed to the highest standards of food safety, good hygiene alone is not enough. It starts with using a growing medium that is demonstrably free from harmful biological contaminants.

Why Vertical Farms Around the World Are Contacting SoilSteam

SoilSteam originally developed its steam technology to enable the safe reuse of biologically contaminated soil and horticultural substrates. Through years of research, including collaborations with leading research institutions, the technology has been shown to effectively eliminate a wide range of plant pathogens and microorganisms while maintaining crop performance.

Today, we are seeing a new trend.

An increasing number of vertical farms, lettuce growers and microgreens producers are contacting SoilSteam—not because they want to recycle their substrate, but because they want to ensure that new substrate is biologically clean before production begins.

“Our original goal was to develop technology that allows contaminated soil and growing media to be safely reused. Today, we are seeing growing interest from producers who want our help to ensure that even brand-new substrate is biologically clean before it enters production. That is incredibly inspiring for us. In our view, the only reliable way to guarantee a biologically clean growing medium is to treat it using equipment that independent third-party research has demonstrated can sterilise the substrate,” says Hans Kristian Westrum, Sales Director at SoilSteam.

An Investment in Food Safety

Product recalls are expensive. Beyond the immediate financial losses, they can severely damage customer confidence, retailer relationships and brand reputation. For producers of lettuce, herbs and microgreens, preventing contamination is almost always far less costly than dealing with the consequences of a recall.

At SoilSteam, we believe the future of greenhouse and vertical farming should be built on three fundamental principles:

• A biologically clean growing medium.
• Safe and sustainable substrate reuse.
• Lower carbon emissions without compromising food safety.

As food safety standards continue to tighten around the world, we believe clean substrate will become a new benchmark for professional horticulture. We are proud that SoilSteam’s technology can help growers produce safer food while contributing to a more sustainable and circular agricultural industry.

The post Clean Substrate Can Be the Difference Between Safe Food and Costly Product Recalls appeared first on SoilSteam International.

For decades, peat has been the backbone of modern plant production. However, with increasing focus on climate impact, biodiversity, and sustainable resource management, the entire industry is facing a necessary transition. The question is no longer whether we need to reduce our reliance on peat—the question is how we do it.

Today, significant research efforts are being directed toward developing new and more sustainable growing media. Coconut coir, wood fiber, bark-based products, and a range of other alternatives are being developed and tested around the world. These initiatives are important and will undoubtedly contribute to a more sustainable future for horticulture.

However, during the discussion in Amsterdam, SoilSteam highlighted a perspective that often receives too little attention:

The most sustainable substrate is the substrate that has already been produced.

Why Replace a Substrate That Can Still Be Used?

Every year, millions of cubic meters of growing media are transported to greenhouse operations around the world. After a single growing season, much of this material is replaced with new substrate—even though it often retains excellent physical properties.

For several years, SoilSteam has focused on one key question:

Can substrate be treated and reused without compromising yield or crop quality?

The answer is becoming increasingly clear.

Documented Results from Leading Research Institutions

In collaboration with organizations such as Proefcentrum Hoogstraten in Belgium, SoilSteam has conducted extensive trials to document the effects of steam treatment and substrate reuse.

The results show that strawberries grown in steam-treated, reused substrate achieve yields comparable to those grown in new substrate.

This is no longer limited to small-scale research trials.

Several of Belgium’s largest strawberry growers are now conducting full-scale commercial trials, where entire greenhouses are grown on steam-treated and reused substrate and directly compared with greenhouses using new substrate.

The results so far are highly encouraging:

The yields are the same.

We are seeing similar results from ongoing full-scale trials in tomato and pepper production.

The Road Ahead: More Research and More Documentation

While the results are very promising, this is only the beginning.

SoilSteam will continue collaborating with some of the world’s leading researchers and research institutions to document the effects of substrate reuse across more crops, more substrate types, and a wider range of growing conditions.

Our objective is not simply to prove that reuse is possible.

Our objective is to demonstrate that substrate reuse is:

• Sustainable
• Safe
• Agronomically sound
• Economically profitable

One of the Greatest Economic Opportunities in Modern Horticulture

For growers, this is not only about sustainability.

It is also about economics.

By steam-treating and reusing their own substrate, growers can reduce substrate-related costs by up to 80% compared with purchasing new substrate year after year.

At the same time, growers gain:

• Full control of their own substrate
• Predictable costs
• Reduced exposure to rising substrate prices
• Lower transportation costs
• Less dependence on global supply chains
• Improved biosecurity and greater control over substrate hygiene

Growers no longer need to worry about delivery delays, increasing freight costs, or whether incoming substrate is as clean and reliable as expected.

A Powerful Climate Measure

The production and transportation of new substrate represent a significant share of the carbon footprint associated with modern horticulture.

By reusing substrate multiple times, growers can dramatically reduce the need for new raw materials while eliminating a substantial portion of the CO₂ emissions linked to substrate procurement.

For many producers, substrate reuse may be one of the most effective climate actions available—without compromising productivity or profitability.

The Future of Substrates Is Circular

The discussion at GreenTech clearly demonstrated that the industry is entering a period of significant change.

New growing media will undoubtedly play an important role in the future.

However, if our industry is to reduce resource consumption, costs, and climate impact on a meaningful scale, we must also ask a fundamental question:

Why use a substrate once when it can be used multiple times?

At SoilSteam, we believe the future of horticulture is not only about finding new substrates.

It is about creating a circular system where valuable resources are reused again and again—delivering the same yields, lower costs, and a dramatically reduced environmental footprint.

That is what we mean when we say that the future of substrates is circular.

You can use our calculator to estimate how much money and CO₂ emissions you could save by steam-treating and reusing your substrate instead of purchasing new material every season: https://substratecalc.com/

The post The Future of Substrates Is Not Just About New Materials – It’s About Reuse appeared first on SoilSteam International.

The post Steamed reused substrate is as good as fresh in new Proefcentrum Hoogstraten research appeared first on SoilSteam International.

The reason peat and coconut fiber (hereafter referred to as substrate) have become so popular is that they are clean, homogeneous growing media, completely free of fungi and other pests. Substrate is increasingly used for the production of fruits, plants, and vegetables in greenhouses as an alternative to soil. The problem is that after just one season, it can no longer be guaranteed to be clean. Therefore, producers cannot risk reusing the substrate, as this could lead to poor yields risk farmers cannot afford to take. This is, of course, not sustainable. Fortunately, there is a solution.

Innovative Collaboration for Sustainable Production

In collaboration with the research department of one of Europe’s most renowned strawberry regions, Proefcentrum Hoogstraten, SoilSteam has conducted tests to enable the reuse of substrates. Peter Melis, Strawberry researcher at Proefcentrum Hoogstraten, is very optimistic:

— We have a strong focus on sustainability in our production. Nevertheless, it is a fact that much of strawberry production takes place in substrates that are not reused due to disease presence. There are significant environmental issues related to the extraction of peat-based substrates and therefore heat treatment and reuse may be key to more sustainable production. After assisting SoilSteam during testing, I have high hopes that this method can make reuse possible, says Melis.

Promising Tests with SoilSaver 5

Proefcentrum Hoogstraten and SoilSteam have collaborated to steam-treat 10 m³ of substrate that has already been used in strawberry production. After steaming, researchers at Hoogstraten will attempt to grow new strawberries in the heat-treated substrate and compare the results with strawberries grown in fresh and reused substrate. External research shows that steaming of peat might give good results – something we now aim to verify. SoilSteam are ready to start serial production of the machine if the results are good.

Potential for Global Impact

If the results are positive, this could open up entirely new opportunities for sustainable substrate reuse. Oddbjørn Bergem, CEO of SoilSteam, says:

— We have been steaming soil for many years, but it is exciting to gain more experience with this type of substrate. The operation itself went according to plan, and we are fortunate to work with such a dedicated team at Proefcentrum Hoogstraten. Here, we will obtain solid documentation on whether steam-treated substrate performs as well as new substrate. SoilSaver 5 is a custom made machine for the substrate market according to Bergem.

Zero CO₂ Emissions with New Technology

The steaming in Hoogstraten, Belgium, was carried out using the brand-new SoilSaver 5 machine from SoilSteam. This is a 100% electric machine, which means the process is entirely CO₂-free. This makes the technology a sustainable alternative that not only reduces the environmental impact associated with substrate production but also the reuse process itself.

See a short movie of the process here

The post Innovative Project with Great Potential: Reusing Substrates Can Improve the Sustainability of Strawberry Production appeared first on SoilSteam International.