Welcome one more day to our Blog. We have previously talked about the protective role of starters in food. In today’s post we want to dig a little deeper into these preservation mechanisms, which also include their action against Gram-negative bacteria (enterobacteria, Salmonella or E. coli). Keep reading to learn more!

How do starters preserve against food contaminating microorganisms?

In this previous entry of our Blog we have already defined the fermenting bacteria, those that in addition to providing a protective function against the action of harmful microorganisms, improve certain organoleptic characteristics of the food. The mechanisms through which these starters carry out the preservation are: competition, growth markers and growth inhibitory metabolites.

Each one of the different starters has its own mechanism of action and level of activity. We can find bacteria with a wide-spectrum of efficacy against spoilage microorganisms. This antimicrobial spectrum includes activity at low concentrations against spoilage bacteria or Gram-positive food pathogens, but also extends to Gram-negative bacteria sub-lethally damaged by heat treatments or chelating agents. These starters potentially inhibit common food pathogens such as Listeria monocytogenes, Salmonella or Clostridium botulinum, among others.

What is the mechanism of action of the starters against different bacteria?

Starters possess antimicrobial activity that can be bacteriostatic or bactericidal, which is related to the cystine content. Taking this into account, three spectrum of action are established:

  • Narrow inhibitory spectrum, inhibiting only microorganisms of the same species.
  • Intermediate inhibitory spectrum, inhibiting other genus of LAB, Gram-positive bacteria and pathogens present in food.
  • Wide inhibitory spectrum, acting against a large number of Gram-positive bacteria.

There are also numerous starters that extend their range of action by inhibiting other bacterial species, pathogenic fungi and even viruses. Against Gram-negative bacteria, the inhibition is lower since they have the presence of a lipopolysaccharide outer membrane that acts as a very effective permeability barrier. However, a synergistic effect with other treatments such as high pressures (HPP) can improve this inhibition. Or also the use of chelating agents that make the cell wall and membrane of these bacteria permeable.

Can the safety of the final food be compromised by the use of starters?

As we have been saying, the only requirement for a starter to be accepted for use in food is that it must be safe in its application.

There is a widespread use of starters in the meat, dairy and fish industries, even though these are microorganisms which are already present in this type of food without being added. They are even considered to be commonly used ingredients (such as, for example, paprika used in the manufacture of a “chorizo”). These cultures are reflected in numerous lists and documents relating to the safety of international organizations such as the EFSA or the USDA. Others, such as the Danish list, evaluate the safety of cultures according to the following criteria: isolated, identified, safe and non-resistant strains.

In short, the use of starters such as those of Amerex does not compromise the safety of the final food in any case.

And considering organoleptic characteristics, can the use of starters as natural preservatives affect the taste of food?

In response to this question, the most general answer would be that depending on the dosage and the type of starter used, the organoleptic aspects of the food could be modified.

Normally, starters are used in low dosages, which provides an organoleptic advantage, i.e. they do not significantly affect the flavour, texture or aroma of the food. However, it is true that there are some starters that ripen the product and, therefore, can have a greater influence on the change in flavour. In fact, in many cases their use can even improve the flavour and aroma of the food. There are also other types of starters that do not influence the flavour because they do not participate in the ripening of the product, this is the case of the preservative starters.

For example, in cheese manufacturing, starters play an important role in the ripening process, which involves the transformation of milk components into lactic-acid and other compounds, resulting in characteristic flavours and aromas. In this case, starters are essential to achieve the desired flavour in cheese and, therefore, their use not only does not negatively affect the flavour, but is essential to obtain a quality product. Or in the production of breads and bakery products, where starters are used for the production of sourdough, which in turn contributes to the fermentation and final flavour of the product. Or in the case of sausages, where the use of ripening starters is widely known to give the final product very specific flavour, aroma and texture characteristics.

In the case of the use of starters as natural preservatives, there is no significant impact on the organoleptic characteristics of foods, but the starters are mainly used to control bacterial growth. For example, in the production of cooked meat products, starters are used to control the growth of pathogenic bacteria and improve food safety, and their use does not significantly influence the flavour, aroma or texture of these products. It is true that by controlling the development of contaminating bacteria, the appearance of commercial defects such as syneresis or slime, which are changes perceptible to the senses, are avoided.

Unlike chemical preservatives, starters do not usually leave residues or significantly alter the nutritional quality of foods. In addition, these additives can have a negative effect on the taste, texture and aroma of foods, so using natural, healthy and sustainable alternatives to them is a good step.

Bread, cheese and sausages made with starters. Image by Freepik

Where can I find natural starters that act against microorganisms such as enterobacteria, Salmonella or E. coli?

Enterobacteria or pathogens such as Salmonella or E. coli are a common concern in the food industry, as they can cause food safety problems and affect product quality. That is why the use of natural preservatives has become an attractive alternative to traditional chemical preservatives.

At Amerex, we offer a wide range of natural preservatives that include these that act against Gram-negative bacteria, preventing their growth and thus helping to extend the shelf-life of foods. Our Safemix® range of natural flavourings obtained by fermentation is based on different solutions, such as Safemix-AV, a specialist for serious problems with enterobacteria (some of which are highly pathogenic for humans), or Safemix-LS, a specialised starter combination solution for Listeria and Salmonella. All our blends are safe and effective for use in the food industry and comply with food safety standards and regulations.

Plus, our natural preservatives do not adversely affect the flavour, aroma or texture of the food, which allows us to maintain the organoleptic quality of the products. This is especially important in those foods that are sold under clean labels.

Contact us to learn more about these effective natural solutions for the control of Gram-positive and Gram-negative microorganisms in food.

Phone number: +34 91 845 42 14

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