Hello everyone and welcome once again to Amerex’ Blog which continues with a very interesting post for food manufacturers that follows the consumer demand for natural or minimally processed foods and without chemical additives in their composition. In this line, the food industry has worked and continues to work in the application of biotechnology to develop safe and effective foods against contaminating microorganisms.

Which are the mechanisms of natural preservation by lactic-acid bacteria (LAB)?

Lactic acid bacteria are a group of fermenting and lactic-acid producing bacteria, which helps the industry to give certain qualities to the foods as well as a protective function against the action of other harmful microorganisms.

These starters rely on various mechanisms to carry out this protective function. These include the traditional mechanisms of competition as well as food ripening, growth markers or the generation of a wide variety of metabolites that inhibit the growth of other bacteria (such as bacteriocins).

Each starter has different mechanisms of action and levels of activity. We can find bacteria with a wide spectrum of efficacy against spoilage microorganisms, both Gram-positive and Gram-negative. It is worth mentioning that bacteria that are similar to their competitors usually find the mechanisms for their inhibition.

Keep reading to learn a little bit more about these natural preservation mechanisms with starters!

How can a starter preserve naturally through competition and ripening?

The best known way of preservation by starters is through the ripening of the product. This normally includes an organoleptic change in the product by acidification. However, there are other starters in which their protective capacity is also linked to their growth, but not necessarily to a transformation by fermentation. We are talking about preservation through competition: a high number of harmless bacteria competing for food and culture medium, making it difficult for invasive microorganisms to thrive.

How can a ferment naturally conserve through metabolites and growth markers?

As the starter cultures grow, they leave a trace of their growth in the culture medium or in the food matrix, which is what we call “growth markers“. Thus, bacteria similar to these starters understand that this is not the best place to survive, so this is another natural conservation mechanism provided by starters. This includes metabolites that are developed by all of them as they grow. Obviously, there will be bacteria that are more specialized than others in their growth. These metabolites are very small peptides that are denaturized when in contact with human saliva, they are safe and like their bacteria, they do not create resistance to antibiotics.

In which foods does the food industry apply the use of starters as natural preservation mechanisms?

When we talk about natural food preservation, protective starters are highly effective in the preservation of a wide variety of foods such as meat, dairy products, fish, beverages, sauces… among others.

Some examples of the most common applications of these microorganisms and mechanisms in different foods are the following:

  • In meat products they are used to inhibit pathogens such as L. monocytogenes, E. coli, St. aureus, C. botulinum or Salmonella.
  • In dairy products they are more widely used, and their antimicrobial activity is mainly focused on the inhibition of Clostridium and Listeria. In cheese, for example, they are used for ripening and controlling spoilage bacteria.
  • In fish for preventing the appearance of Listeria in mass applications, as well as in injected or surface treatments.
  • In ready meals to extend shelf life by controlling pathogens and other bacteria that cause unwanted acidification.
  • In beverages and sauces, in addition to preventing the appearance of spoiling bacteria, to reduce the use of treatments and additives that help the food to have a fresher and more homemade appearance and flavour.
  • In bakery to directly and effectively fight moulds and yeasts, or the development of Listeria in those products that are more critical due to their pH and water activity.
  • In vegan products such as cheese and meat analogues for a controlled fermentation to improve the flavour of the final food.

As you can see, biotechnology is a great tool to naturally guarantee food safety and improve its sensorial and physico-chemical characteristics.

What legislation supports the application of starter cultures in the food industry?

As we have mentioned, there are many references to the fermenting bacteria traditionally used in the industry, which are collected in databases such as that of the EFFCA (European Food & Fermentation Culture Association).  Therefore, we can define lactic-acid bacteria as a characteristic ingredient of food. When catalogued as an ingredient, another reference is the European Regulation (EC) No. 178/2002, which simply states that good manufacturing practices, responsibility and safety are the conditions that a starter must comply with.

Is the safety of the starters guaranteed in their application onto the final food?

Lactic-acid cultures are referenced in documents and lists such as the EFSA QPS, the Danish list of their Ministry of Food, Agriculture and Fisheries, or the USDA GRAS list, where most commercial lactic-acid bacteria are considered safe. These lists are based on the collection of exhaustive studies about the entire metabolism of these bacteria under all possible circumstances.

In particular, the Danish list evaluates the safety of the strains according to the following criteria (and with the same objective as 178/2008):

  1. Identification: The micro-organism must be identified by an analytical method approved for species identification.
  2. Purity: Studies must be conducted to ensure that the micro-organism formulation does not contain potentially harmful organisms and/or large amounts of contaminating organisms of unknown identity
  3. Adverse effects: Absence of potentially pathogenic properties in humans or animals must be demonstrated. If the organism has the ability to produce toxins, it must be shown that these are not formed in harmful quantities during the particular application
  4. Antibiotic resistance: It must be proved that the micro-organism does not possess transferable antibiotic resistance.

Ultimately all these references guarantee the same thing, that the starter must be safe in its application.

Where can I learn more about starter cultures for natural food preservation?

You can see that the use of starters is of great interest to the food industry due to their potential as antimicrobials and their ease of application in numerous food matrixes. They are valuable candidates to consider in the replacement of E-number chemical preservatives, which follows the market trends of consuming more natural foods.

Amerex has its own range of products completely focused on the preservation of the final food by means of natural protection mechanisms. As a result, we provide solutions to the main challenges of the industry in different matrixes, such as the appearance of Listeria or Salmonella in dairy products, or Clostridium botulinum in cooked meat products. These are three examples of many others considering the variety of pathogens and contaminating microorganisms in general, and the many applications that exist in the food industry.

If you have any remaining questions about these biotechnological mechanisms for food safety, we will be happy to answer them and discuss all possible strategies for your food manufacturing.

Phone number: +34 91 845 42 14

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