Lactococcus lactis bacteria protecting a smoked sausage from mold.

Natural Preservatives: Can These Bacteria Replace Chemicals in Our Food?

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Mira Elwood in Science & Nature December 2025 • 4 min read.

"Discover how Lactococcus lactis strains offer a safe, effective alternative to chemical preservatives for smoked sausages and other foods."


Food spoilage caused by bacteria and fungi is a widespread issue, leading to both economic losses and potential health risks from toxins produced by these microorganisms. While chemical additives and physical treatments have been used to combat spoilage, concerns about their safety have prompted a search for natural alternatives.

Lactic acid bacteria (LAB), particularly Lactococcus lactis, have emerged as promising biopreservatives. These bacteria, traditionally used in food fermentation, are recognized as safe and possess antagonistic properties against various microorganisms. This is due to their production of organic acids, diacetyl, bacteriocins, and low-molecular-weight substances with antifungal activity.

A study aimed to isolate and identify new antifungal Lactococcus strains and evaluate their potential use in preventing fungal spoilage. The research focuses on Lactococcus lactis strains that synthesize bacteriocins, antimicrobial peptides that can inhibit the growth of closely related bacteria and fungi. This approach offers a natural way to enhance food safety and reduce reliance on synthetic preservatives.

How Can Lactococcus lactis Protect Food from Spoilage?

Lactococcus lactis bacteria protecting a smoked sausage from mold.

The research involved isolating Lactococcus strains from raw milk, dairy products, and fermented drinks like kurunga, kumiss, and Iranian "Dough" from various climatic regions. These sources were selected due to their historical use in preventing diseases, suggesting the presence of beneficial bacteria.

Researchers focused on isolates with antagonistic activity, identifying them as Lactococcus lactis ssp. lactis based on morphological, cultural, physiological, and biochemical properties, as well as 16S rRNA gene sequencing. Out of 94 strains, only nine exhibited a broad spectrum of activity against both Gram-positive and Gram-negative bacteria, including pathogens, molds, and yeasts.

  • Staphylococcus aureus
  • Escherichia coli
  • Pseudomonas aeruginosa
  • Proteus vulgaris
  • Salmonella gallinarum
  • Aspergillus
  • Fusarium
  • Penicillium
  • Rhodotorula
  • Candida
Two strains, 194 and K-205, isolated from raw cow milk and kurunga from Buryatia, demonstrated particularly high antibiotic activity, surpassing that of nisin and fungicidal antibiotics like nystatin. These strains were then tested on raw smoked sausages infected with fungi, identified as Eurotium repens de Bary.

A Promising Future for Natural Food Preservation

The study's findings indicate that treating raw smoked sausages with Lactococcus lactis strains 194 and K-205 effectively inhibits the growth of spoilage microorganisms, extending shelf life while adhering to established quality standards. This suggests that Lactococcus lactis strains can potentially replace chemical preservatives, offering a safer and more natural approach to food preservation.

About this Article -

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This article is based on research published under:

DOI-LINK: 10.3844/ajabssp.2010.477.485, Alternate LINK

Title: New Antifungal Bacteriocin-Synthesizing Strains Of ≪I≫Lactococcus Lactis≪/I≫ Ssp. ≪I≫Lactis≪/I≫ As The Perspective Biopreservatives For Protection Of Raw Smoked Sausages

Subject: General Agricultural and Biological Sciences

Journal: American Journal of Agricultural and Biological Sciences

Publisher: Science Publications

Authors: Stoyanova

Published: 2010-04-01

Everything You Need To Know

1

What is the main function of *Lactococcus lactis*?

The primary role of *Lactococcus lactis* is to act as a natural food preservative. It achieves this by producing substances that inhibit the growth of spoilage microorganisms such as bacteria and fungi. These substances include organic acids, diacetyl, bacteriocins, and low-molecular-weight substances. These properties make *Lactococcus lactis* a promising alternative to chemical preservatives.

2

Why is *Lactococcus lactis* important?

Food spoilage is a significant issue that leads to economic losses and potential health risks due to toxins produced by bacteria and fungi. *Lactococcus lactis* is important because it offers a natural and safer method to combat spoilage. By utilizing *Lactococcus lactis*, food producers can extend the shelf life of products such as smoked sausages, reduce reliance on synthetic preservatives, and improve food safety.

3

How does *Lactococcus lactis* work to preserve food?

*Lactococcus lactis* works by producing several compounds that inhibit the growth of other microorganisms. These include organic acids, diacetyl, bacteriocins, and low-molecular-weight substances. These substances have antifungal activity. Bacteriocins, in particular, are antimicrobial peptides that target and inhibit the growth of closely related bacteria and fungi. This multifaceted approach allows *Lactococcus lactis* to effectively prevent spoilage and maintain food quality.

4

What did the research on *Lactococcus lactis* focus on?

The research examined *Lactococcus lactis* strains for their ability to prevent fungal spoilage in food. The study isolated strains from various sources, including raw milk, dairy products, and fermented drinks. The two strains 194 and K-205, isolated from raw cow milk and kurunga, demonstrated strong antifungal activity. These strains were tested on raw smoked sausages infected with *Eurotium repens de Bary*, showing that *Lactococcus lactis* can effectively inhibit the growth of spoilage microorganisms and extend shelf life.

5

What are the implications of using *Lactococcus lactis* in food preservation?

The study highlights the potential to replace chemical preservatives with natural alternatives. *Lactococcus lactis* offers a safer and more natural approach to food preservation. By using *Lactococcus lactis*, producers can reduce the need for synthetic additives and offer consumers products with a cleaner label. The implications are a move toward healthier food options and a reduced risk of exposure to potentially harmful chemicals.

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