Microbial food cultures facts for kids

Microbial food cultures are tiny living things like bacteria, yeasts, or moulds. People use them to make many different foods. These tiny helpers cause a process called fermentation.

Humans have used fermentation for thousands of years, even since the Stone Age! Fermentation helps keep food fresh for longer. It also makes food taste better and adds good nutrients. In some parts of Europe, fermented foods make up a big part of what people eat. Scientists have found over 260 different types of these helpful microbes used in foods all around the world.

Scientists like Louis Pasteur started to understand how these microbes work in the 1800s. Today, scientists continue to study them closely. They look at their types, how they work, their chemistry, and their genes. This helps us understand and improve how we make traditional foods. It also helps us find new ways to use these amazing microbes.

A Look Back in Time

Tiny living things, or microbes, were the first life on Earth, appearing over three billion years ago! Our ancestors learned how to use these microbes to make new foods. They did this even before they understood the science behind it.

Key Discoveries

• 1665: Robert Hooke and Antoni Van Leeuwenhoek were the first to see and describe microbes.
• 1857–1876: Louis Pasteur showed that microbes are key to making lactic acid and alcohol through fermentation.
• 1881: Emil Christian Hansen found a pure yeast called Saccharomyces carlsbergensis. This yeast is now widely used to make lager beer.
• 1889–1896: Scientists like Herbert William Conn showed that bacteria make milk and cream sour.
• 1897: Eduard von Freudenreich found a bacterium called Lactobacillus brevis.
• 1919: Sigurd Orla-Jensen sorted lactic acid bacteria based on how they act.
• 1970s onwards: Companies started making concentrated, frozen, or freeze-dried cultures. These make food production more consistent.

How Microbes Help Our Food

Microbial food cultures help keep food fresh. They create things like organic acids (like lactic acid) or alcohol. These stop bad microbes from growing. They also reduce the water in food, which helps preserve it. Plus, these good microbes can stop harmful germs from growing.

Microbes also make food healthier and taste better. There are three main groups of microbial food cultures: bacteria, yeasts, and moulds.

Bacteria

Bacteria used in food can be divided into two main types: starter cultures and probiotics.

Starter cultures are used in food making. They help create the taste, smell, color, and texture of food. They also help keep food safe and make it more nutritious.

Probiotics are special microbes that can give health benefits when you eat them.

Most of the time, the bacteria used as starter cultures are different from probiotics. But sometimes, a bacterium can do both jobs! Scientists are still learning more about how microbes help both food and our bodies.

The most important bacteria in food making are Lactobacillus species. These are part of a group called lactic acid bacteria.

Bacterial food cultures give cheeses and fermented milk products their unique taste and texture. Think of yogurts, ayran, skyr, or ymer. They also help make the flavor and color of salami and dried ham. In wine, lactic acid bacteria change a sour acid into a stable one. This makes high-quality wines taste better as they age.

Lactic acid bacteria are also used in food supplements. They act as probiotics to help balance the good bacteria in your gut.

Yeasts

The most famous yeast in food is Saccharomyces cerevisiae. People have used it for thousands of years to make bread and beer.

When you make bread, S. cerevisiae eats the sugars in the dough. It then makes carbon dioxide gas. This gas creates bubbles, making the dough rise and the bread light and fluffy.

Different yeasts are used to make beer. They turn sugars from malted barley into alcohol. S. cerevisiae is used for ale-type beers. It's called a top-fermenting yeast because it makes foam on top. For lagers, bottom-fermenting yeasts like S. pastorianus are used. These yeasts ferment more sugars, giving lagers a cleaner taste.

In wine, yeast turns the sugars in grape juice into alcohol. Yeast is naturally found on grape skins. But often, a pure yeast culture, usually S. cerevisiae, is added to make sure the fermentation works well. Other yeasts can be added to create special flavors. Sparkling wine gets its bubbles from a second fermentation in the bottle.

Yeasts are also used to make kefir, some soft cheeses, and fermented soy drinks.

Moulds

Three main types of cheese get their special qualities from moulds: blue cheese, soft ripened cheese (like camembert and brie), and rind-washed cheese (like époisses and taleggio).

To make blue cheese, a mould, usually Penicillium roqueforti, is added to the cheese curds. As the cheese ages, the mould grows, creating blue veins and its unique flavor. Examples are stilton, roquefort, and gorgonzola.

Soft ripened cheeses like brie and camembert are made by letting P. camemberti grow on the outside. This mould forms a soft white crust, and the inside becomes creamy with a strong flavor.

Rind-washed cheeses like limburger are washed with salty water and other ingredients like beer or wine. This helps moulds and bacteria grow, adding to their flavor.

Moulds are also used to ripen sausages. Different moulds, like P. chrysogenum, help develop the aroma and improve the texture of sausages. They also help the sausages ripen faster and stay fresh longer.

In the past, soy sauce was made by mixing soybeans and grains with mould (like Aspergillus oryzae) and yeast. This mixture was left to ferment in the sun. Today, soy sauce is made under controlled conditions. The main flavors come from salts of glutamic acid, like monosodium glutamate.

Making Microbial Food Cultures

Companies make microbial food cultures very carefully. First, a lab prepares a small amount of pure microbes. Then, these microbes are grown in large tanks or on surfaces under special conditions. Once they have grown enough, they are collected, sometimes mixed with other cultures, and then prepared for shipping and storage. They are sold as liquids, frozen, or freeze-dried products.

Another, older way to start fermentation is called "spontaneous fermentation." This uses microbes that are naturally present, for example, in raw milk. Or, people might use a small part of a previous batch of food to start a new one. This method is becoming less common in many countries. This is because it can sometimes lead to harmful germs growing.

Microbial Protein

Microbial protein (MP) is protein made from tiny living things like micro-algae, bacteria, yeasts, and microfungi.

Some examples of microbial protein products you might find are:

• Quorn
• Solein by Solar Foods

Microbial protein can be used instead of meat and animal feed. This helps reduce the harmful effects of meat production on the environment. It can also replace animal-based protein supplements.

Scientists are working to make microbial protein production even better for the environment and cheaper. They are also trying to figure out how to make it on a very large scale.

Good for the Planet

Studies show that making microbial foods using solar energy and direct air capture uses much less land than growing traditional crops. For example, growing food from air can produce 10 times more protein and at least twice the calories than growing soybeans on the same amount of land.

Another study found that if just 20% of the beef we eat was replaced by microbial protein, it could greatly reduce deforestation (by 56%) and help fight climate change by 2050.

Single-cell protein can also replace regular protein in animal feed. This is helpful because it doesn't depend on land or get affected by things like droughts or floods.

Keeping Food Safe

Microbial food cultures are seen as traditional food ingredients. They are allowed in food production all over the world under general food laws.

The microbial food cultures sold to companies are usually mixtures of one or more types of microbes. They also contain things needed for the microbes to survive, be stored, and be used easily in food production.

The safety of these cultures is checked based on their type, species, or specific strain.

Microbes with a Safe History

Groups like the International Dairy Federation (IDF) and the European Food and Feed Cultures Association (EFFCA) created a list in 2001. This list showed microbes that have been safely used in food for a long time.

This list was updated in 2012. It now includes microbes used in many foods, like dairy, fish, meat, drinks, and vinegar. It also has updated names for the microbes.

See also

In Spanish: Cultivos alimenticios microbianos para niños