Here you will discover the key aspects to consider when pasteurizing or sterilizing your truffle-based gourmet preserves or prepared dishes, whether featuring or flavored with this underground mushroom.

Preserving the truffle’s aroma and its distinct flavor profile in your product is one of the biggest challenges with this type of preserve. So pay close attention. Let’s get started!

Truffles: Beneficial for health

Truffles are a type of fungus that grows near the roots of certain trees, such as oak or holm oak.

In addition to being highly valued for their pleasant aroma and delicious taste, they are also known for being rich in:

Carbohydrates, protein and fiber

Truffles are rich in carbohydrates, protein, and fiber—key elements for a balanced, healthy diet.

Micronutrients

They contain vitamin C, phosphorus, sodium, calcium, magnesium, manganese, and iron.

Antioxidants

These compounds help combat free radicals and prevent oxidative damage to cells.

Truffle consumption

The main producers of black truffle worldwide are France, Spain, and Italy. In Europe, annual production ranged from 22 to 134 tons of black truffle from 1990 to 2007, representing 90% of global production.

Although the number of truffle plantations is increasing and countries like Australia, the United States, and New Zealand have also started producing, current production only meets about 10% of global demand.

In 2010, the worldwide annual demand for truffle was approximately 900 tons, while the average annual production was less than 100 tons.

Types of truffles

There are over seventy species of truffles worldwide, with thirty-two found in Europe, though not all are edible. Among those that are, the most notable include:

Tuber melanosporum: Black winter truffle or Périgord truffle. This is the most commonly used variety in cooking.
Tuber magnatum: White truffle, Piedmont truffle, or tartufo bianco. Known as the most delicious and prized truffle in the world, it grows wild in the Piedmont region, Tuscany, and other areas in Italy and Istria (Croatia).
Tuber aestivum: Summer truffle or St. John’s truffle. Frequently used in preserves, it can be mistaken for black truffles due to its similar external appearance. However, its interior is hazel-colored with white veins.
Tuber brumale: Winter truffle or musky truffle. It’s the least commercially sought after and, like the summer truffle, is often used in preserves.
Tuber indicum or Chinese truffle: As the name suggests, it originates from China. While it resembles the black truffle, its quality is lower. In cooking, it’s typically used to garnish and flavor dishes.

Important:

Before applying a thermal treatment process, it’s essential to understand factors such as the food's heat resistance, and the stability of its flavor and texture after thermal processing. Different truffle varieties may require specific thermal treatments and preservation methods to maintain their quality and safety.

Truffle-Based Preserves and Prepared Dishes

The most common truffle-based preserves and prepared dishes on the market include:

Regardless of the type of truffle preserve or prepared dish, all these products must undergo a preservation process before they can be sold to comply with current health and hygiene regulations and to ensure long-lasting quality.

How to make truffle preserves and prepared dishes

Before starting any type of truffle preserve or prepared dish, the first step is to ensure you have the necessary containers in good condition—neither cracked nor deformed. The same applies to the lids, if they are used.

Next, proceed to wash the truffles, either with chlorinated or regular water.

Information:

Chlorinated water is commonly used for cleaning in the food industry, as it helps reduce the microbial load on food surfaces. However, the use of chlorinated water must be carefully controlled to avoid any negative impact on the flavor or quality of the truffles.

After washing, let the truffles air-dry on a clean, absorbent surface in a controlled environment, or use industrial fans to apply gentle air. This step helps to remove excess moisture from the truffles and is crucial for preventing the growth of molds and other microorganisms.

Once dried, we perform a manual brushing. This brushing helps maintain the physical and sensory quality of the truffles, removing any remaining dirt and residues without damaging them. Once clean and sorted, we begin the cooking process.

There are generally two cooking methods for truffle preserves:

Single-cook method

The fresh truffle is packaged and then sterilized.

It is crucial that the cooking temperature and time are carefully controlled to prevent any impact on the organoleptic properties of the truffle preserve.

Double-cook method

The truffle undergoes an initial cooking with water and salt.

This first cooking is done at a low temperature for a specific duration, allowing the truffle to release some of its juice and lose weight without affecting its organoleptic properties.

Next, the truffle juice is extracted, and the truffle is packaged in its final container along with some of the juice.

Finally, a second sterilization is performed in the autoclave for a short period.

It’s essential to maintain aseptic conditions between steps to ensure food safety throughout the process.

If, on the other hand, the truffle is used in a preserve to infuse its aroma, place the food together with a truffle in an airtight container. Seal it and let it sit for at least 24 hours. The fattier the food, the more aroma it will absorb from the truffle. Once the food has taken on the truffle’s properties, prepare it as you normally would.

Alternatively, if using truffle as an ingredient, for example, in truffled wild mushroom pâté or caramelized onions with truffle, follow the specific recipe for the dish and add grated truffle either during cooking or afterward. The preservation method to apply will depend on the characteristics of each preparation.

Sterilizing canned truffles

Most gourmet truffle preserves and truffle-based prepared dishes are sterilized. However, sterilization can be too harsh on certain foods if not carefully controlled.

To address this, it’s essential to balance the preservation of aromatic compounds with the need for effective and safe thermal processing. The priority should always be to minimize the loss of the product’s aroma.

Truffle preserves can be packaged raw and then sterilized (single-cook method) or pre-cooked, packaged, and then sterilized (double-cook method). In the latter case, as the truffles have already been cooked, a lower F₀ value is usually applied than if they were raw.

For truffle-based prepared dishes, the recipe is first followed to prepare the dish, then raw truffle (sliced or in pieces) is added before packaging, followed by pasteurization or sterilization.

Remember that sterilization uses higher temperatures, providing a longer shelf life and eliminating the need for refrigeration during transport or storage. Pasteurization, on the other hand, uses lower temperatures, making it gentler on your preserve but resulting in shorter best-by dates.

When deciding between thermal treatments, consider the type of food and the desired outcome.

Sterilization eliminates nearly all microorganisms, while pasteurization does so partially.

Both processes yield safe, reliable results without posing any risk to consumer health.

To sell your preserves, it’s essential to comply with food safety regulations, particularly for the sterilization of low-acidity foods, ensuring quality, hygiene, and consumer protection. This requires applying thermal treatment with professional equipment and recording the treatment results for each batch, as our TERRA Food-Tech^® autoclaves do.

pH of canned truffles

Truffles generally have a near-neutral pH, between 6 and 7.5, depending on the truffle type and the soil in which they grew. However, the pH of the final product in a gourmet preserve or prepared dish will depend on the additional ingredients and preparation method used.

The pH of a food, among other factors, determines the temperature and duration of thermal treatment, as it affects the thermal resistance of present microorganisms.

F₀-P₀ values for truffle sterilization

For truffle preserves and truffle-based prepared dishes, an F₀ value of 8–10 is applied at a temperature of approximately 112–115ºC, although this may vary depending on the accompanying ingredients.

It’s important to note that these values are approximate, as the F₀ and P₀ thermal values depend on the type of product, its ingredients, and the preparation method used.

We recommend evaluating each product individually by accurately measuring its pH and performing subsequent checks to assess the entire process, allowing you to select the most appropriate F₀-P₀ values for the final product.

Common issues in truffle sterilization

Truffles often have a high microbial load since they grow about 20 cm below the surface.

For this reason, we emphasize the importance of thoroughly cleaning them and removing any impurities, bruises, or rot. After cleaning, make small surface cuts to check their maturity. Then, truffles should be sorted and calibrated to determine their category based on quality parameters.

It’s also essential to dry them well to minimize future microbial growth.

Next, a blanching process is performed in water at 85–100°C for 1–3 minutes, which halts enzymatic reactions. This step serves as the initial phase of preservation treatment used for some mushroom species.

When it comes to sterilizing truffle preserves or truffle-based prepared dishes, selecting the correct parameters is crucial, as this can affect the texture of the truffle. Truffles are highly sensitive to heat, and excessive temperatures may damage them, risking a complete loss of aroma or even burning.

Regarding the Bacteria and Fungi Commonly Found in Truffles, Clostridium botulinum is notable, though there are other potential biological hazards to consider:

MAIN BIOLOGICAL HAZARDS
Microorganisms	Bacteria	Salmonella	Clostridium botulinum
		Bacillus sp.	Clostridium perfringens
		Escherichia coli	Listeria monocytogenes
	Fungi	Trichoderma sp.	Aspergillus sp.
		Alternaria sp.	Cladosporium sp.
		Streptomyces sp.	Penicillium sp.

Recommended containers for truffle sterilization

Truffle preserves, being a gourmet product, are primarily sold in glass containers. If this is your preferred option, be sure to leave some headspace between the truffle and the lid when filling the glass jar.

For truffle-based prepared dishes, glass jars, cans, or plastic trays are commonly used, depending on the final product.

Many of you ask us which type of container is best for your creations. However, at TERRA Food-Tech^®, we can’t recommend one over another, as the choice depends on the type of preserve, your budget, and your preferences.

What we can do is provide insight into the pros and cons of each type of container and let you know that our autoclave is suitable for use with any container type.

Sterilizing truffles with TERRA Food-Tech^® autoclaves

TERRA Food-Tech^® autoclaves allow you 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 feature a rapid cooling system that activates once the thermal treatment is complete.

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

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

Our food autoclaves ensure compliance with safety, quality, and hygiene regulations for canned preserves and prepared dishes. They are essential for anyone looking to market these products.

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

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

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