According to the dictionary, a mushroom is any type of fungus, edible or not, with an umbrella shape supported by a stem, the fleshy column that holds up the mushroom cap. Despite this simple definition, it’s important to remember that all mushrooms are fungi, but not all fungi are mushrooms. The mushroom is the part of the fungus that we can see.

In this section, we’ll not only explain what these mushrooms are, along with their properties and varieties, but also detail what you need to consider when pasteurizing or sterilizing your gourmet preserves or mushroom-based prepared dishes.

Mushrooms: Beneficial for health

Although mushrooms might not seem particularly appealing or beneficial at first glance, they are actually very good for our health, as they contain a wealth of:

Minerals

Rich in iron, phosphorus, iodine, magnesium, selenium, calcium, potassium, and zinc.

Vitamins

A source of vitamin A, B vitamins (specifically B1, B2, and B3), as well as vitamins C and D.

Water

Composed of 90% water with no fat (25 kcal).

Fiber

Provide insoluble fiber, excellent for improving digestive health.

Did you know that mushrooms are neither plants nor animals?

Fungi don’t contain chlorophyll and therefore cannot perform photosynthesis. As a result, to survive, they rely on absorbing carbohydrates from trees and plants.

You’ve probably taken a moment to observe the unique and fascinating physiology of mushrooms. Here’s a breakdown of their different parts:

Mycelium: The underground part, which we don’t see.
Volva: Located at the base, usually bell-shaped.
Stem: The elongated body, often featuring a membrane called the ring.
Cap: Also known as the “head,” which includes the cuticle and the hymenium, the underside.

Mushroom consumption

According to the European Mushroom Growers Group (GEPC), over 1,113,000 tons of edible mushrooms were produced in Europe in 2020, generating more than 1.5 billion euros in annual sales.

Poland and the Netherlands are the largest producers, accounting for 50% of total European production. Spain follows closely with a total of 130,700 tons per year. This sector includes around 2,900 European producers, providing direct employment to over 40,000 people, mainly in rural areas.

Additionally, 70% of mushrooms are sold in retail stores, primarily hypermarkets and supermarkets, while the remaining 30% goes to the food service industry.

The most widely cultivated mushroom variety is the button mushroom, with a total production of 1,063,700 tons in 2020, of which 64% were for fresh consumption and 36% for processing.

Types of mushrooms

Before detailing the types of mushrooms that can be used in preserves or prepared dishes, it’s important to remember that not all mushrooms are edible or safe.

With this in mind, we can categorize mushrooms as follows:

Edible mushrooms

These are tasty and cause no harm to humans.

Mildly toxic mushrooms

These don’t taste good and can cause minor issues such as indigestion, non-severe symptoms like hallucinations, diarrhea, gastritis, vomiting, and tachycardia.

Poisonous mushrooms

These are dangerous. Ingesting them can lead to serious health issues, permanent damage, or even death.

As for common edible mushrooms, the most popular types include:

Mushroom-based preserves and prepared dishes

The most common mushroom preserves and prepared dishes available on the market include:

Mushrooms in brine, olive oil, or vinegar (can be a mix of different mushroom varieties or a single type)
Mushroom pâté
Mushroom cream
Stews and casseroles
Risotto
Mushroom-stuffed pasta

Regardless of the type of mushroom preserve or prepared dish, all these products must undergo a preservation process before being marketed to comply with current health and hygiene regulations and to ensure they are stored with full quality assurance.

How to make mushrooms preserves and prepared dishes

Before starting to prepare a mushroom preserve or dish, it’s important to get organized and ensure you have the necessary containers and lids in good condition—neither broken nor deformed.

Next, discard any mushrooms that are damaged, bruised, or discolored, and clean the good ones with a brush or cloth and a damp cloth. If a mushroom has excess dirt, it’s best to rinse it with cold water, being careful not to soak it.

It’s essential to avoid prolonged contact with water, as mushrooms quickly absorb it, which can affect their texture and flavor during cooking and preservation. Finally, dry them with paper towels or kitchen towels.

Then, sort and calibrate them to determine their category based on quality characteristics.

Once cleaned and sorted, the mushrooms can be prepared as desired, avoiding overcooking. They are then packaged, and a thermal treatment is applied in an autoclave to ensure proper preservation and compliance with food safety, quality, and hygiene regulations.

Recommendation:

If you can’t prepare them immediately, we recommend storing them in the refrigerator. Avoid plastic bags or sealed containers, as these will speed up decomposition. Storing them in paper or perforated containers helps prevent moisture buildup, but it’s very important to keep them refrigerated at temperatures between 1 and 4°C to maintain freshness and prevent microorganism growth before processing.

When beginning thermal treatment, it’s also recommended to blanch the mushrooms in salted water before packaging. This process typically lasts 1–3 minutes at 85–100°C, which helps inactivate enzymes, reduce microbial load, and preserve the texture and color of the mushrooms.

If you are preparing the mushrooms in brine, olive oil, or vinegar, fill a container with the raw mushrooms, add salted water, olive oil, or vinegar. Then, sterilize them in the autoclave.

Information:

Keep in mind that mushrooms may change color during processing, so we recommend submerging them in a pickling solution to lower their pH and prevent darkening.

On the other hand, if your preparation is a mushroom pâté, cream, or ready-made dish, first prepare the dish as desired and then package it, but avoid overcooking. It will finish cooking during sterilization in the autoclave.

Sterilizing canned mushrooms

Most gourmet mushroom preserves and mushroom-based prepared dishes are sterilized. This allows them to be stored at room temperature without refrigeration for an extended period, ensuring quality and preserving all their properties. However, many mushroom-based products on the market are also pasteurized.

When choosing between thermal treatments, consider the type of food and the desired outcome. Sterilization uses higher temperatures, resulting in a longer shelf life without the need for refrigeration. In contrast, pasteurization involves lower temperatures and is less intense, so the product will require refrigeration and have a shorter shelf life.

Sterilization eliminates nearly all microorganisms, while pasteurization does so only partially. Both processes are safe and do not pose a risk to consumer health.

pH of canned mushrooms

The pH is a critical factor for food safety and determines the sterilization process required for canned mushrooms.

Main pH values of canned mushrooms

The pH of a food affects both the temperature and duration required for thermal treatment, as it influences the types of microorganisms that can grow in it. A lower pH (higher acidity) inhibits the growth of pathogenic microorganisms like Clostridium botulinum, while a higher pH promotes their growth.

Edible mushrooms generally have a pH between 5.7 and 6.8, though this can vary slightly depending on the mushroom species and its state (raw, cooked, or preserved).

For prepared dishes, the pH should be measured after cooking. If the pH is above 4.6, high-temperature sterilization (above 100°C) is necessary due to the risk of Clostridium botulinum spore growth. If the pH is below 4.6, a low-temperature sterilization or even pasteurization may be possible, provided the product remains refrigerated.

F₀-P₀ values for mushroom preserves sterilization

Mushroom preserves and mushroom-based dishes are typically sterilized at temperatures above 100°C to ensure the destruction of Clostridium botulinum spores. The recommended F₀ value for these products is generally between 6 and 8, depending on the product’s characteristics.

It’s important to remember that these F₀ and P₀ values are approximate and should be adjusted to each product’s specific conditions, such as pH, ingredients, and type of container used.

Remember that it’s essential to evaluate each food individually once cooked or prepared in its natural state by accurately measuring its pH and conducting subsequent checks to assess the entire process. This allows you to select the most appropriate F₀-P₀ values for each product.

Common issues in mushroom sterilization

During mushroom cultivation, contamination by molds such as Trichoderma, Penicillium, and Aspergillus, as well as bacteria like Pseudomonas fluorescens (which causes “bacterial blotch”), can occur. These issues must be resolved before the packaging and sterilization phase.

One of the main challenges in sterilizing mushroom preserves is ensuring the elimination of heat-resistant microorganisms, such as Clostridium botulinum spores. These microorganisms are not easily destroyed at temperatures below 100°C, making autoclave sterilization essential.

Another challenge in mushroom sterilization is achieving uniform heat distribution during the autoclave process.

Proper heat distribution in the autoclave is crucial to ensure that all parts of the product reach the required temperature for effective sterilization.

This is particularly important for products with varying densities or consistencies, such as mushroom pâtés or creams, where uneven heat distribution could lead to incomplete sterilization.

Recommended containers for mushroom sterilization

Mushroom preserves are typically found in glass jars or cans.

Bags or pouches are also an option to consider, as they allow for faster sterilization by directly transmitting heat.

In this case, it’s important to ensure the pouch material can withstand the high temperatures and pressure of the autoclave.

If you choose a glass jar, be sure to leave some headspace between the food and the lid when filling the container.

For mushroom-based prepared dishes, plastic trays or containers are often used. These plastic containers should be certified for thermal processes, such as polypropylene (PP), as other materials could deform or release unwanted substances during autoclave sterilization.

At TERRA Food-Tech^®, we cannot specify the best container for each preserve or prepared dish, as this will depend on many factors. To make the right decision, you’ll need to consider the type of preserve desired and the cost involved.

What we can do is provide you with the pros and cons of each type of container and assure you that our autoclave is compatible with any container type.

Sterilizing mushrooms with TERRA Food-Tech^® autoclaves

TERRA Food-Tech^® autoclaves offer the ability to cook products before subjecting them to thermal treatments like pasteurization or sterilization. Thanks to the counterpressure they generate, they prevent container deformation. To avoid undesirable overcooking, these autoclaves use a rapid cooling system that activates after the thermal treatment is complete.

If you are looking for reliability, safety, and efficiency in producing gourmet preserves, a food autoclave is the ideal choice.

With TERRA Food-Tech^® autoclaves, you can not only sterilize but also cook and pasteurize—three functions in one device.

Using our food autoclaves ensures compliance with safety, quality, and hygiene regulations for canned foods and prepared dishes. They are essential for those who wish to market these products.

TERRA Food-Tech^® autoclaves were created to meet the needs of micro-entrepreneurs, chefs, cooks, farmers, livestock producers, and social enterprises who have made gourmet preserves their life’s work.

Success stories in mushroom-based preserves and prepared dishes

Mushrooms are an excellent choice for creating preserves and prepared dishes. Nutritious and flavorful, they make a great addition to any meal. That’s why some of our clients have included them on their menus.

Take a look at our success stories section to see just how delicious this ingredient can be and discover the vast commercial opportunities it offers.

Quattro Stagioni

Artisan preserves workshop

Tarro Verde

Preparation of canned vegetables, ready meals and vegetable spreads

Looking to learn more about TERRA Food-Tech^® autoclaves for sterilizing gourmet mushroom preserves? Contact our experts today

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