Lactic acid bacteria protecting Sicilian cheese from Listeria

Unlocking Flavor and Safety: How Traditional Sicilian Cheeses Combat Listeria Naturally

Reese Marlowe in Health & Wellness December 2025 • 5 min read.

"Discover the ancient techniques and the power of lactic acid bacteria in Pecorino Siciliano and Vastedda cheeses to fight foodborne illness and enhance taste."

Foodborne illnesses, especially those caused by pathogens like Listeria monocytogenes, are a major public health concern worldwide. Listeria is particularly dangerous because it can survive in harsh conditions, including the acidic environments and low temperatures often found in food production and storage. This resilience makes it difficult to control, especially in dairy products like cheese, where it can cause serious infections in vulnerable populations such as pregnant women, the elderly, and those with weakened immune systems.

However, cheesemakers have a powerful ally in the fight against Listeria: lactic acid bacteria (LAB). These beneficial bacteria naturally produce substances called bacteriocins, which can inhibit the growth of undesirable bacteria, including Listeria. For centuries, cheesemakers have unknowingly harnessed the power of LAB to create safer and more flavorful products. Now, modern science is catching up, exploring the potential of LAB as a natural way to improve cheese safety and quality.

A recent study focused on traditional Sicilian cheeses, Pecorino Siciliano (PS) and Vastedda della valle del Belice (VB), to investigate the anti-Listeria potential of LAB strains isolated from these unique dairy environments. The research aimed to understand how these natural bacteria can be used to enhance food safety while preserving the distinctive characteristics of these beloved cheeses.

How Do Lactic Acid Bacteria (LAB) Naturally Fight Listeria?

Lactic acid bacteria protecting Sicilian cheese from Listeria

The study began by isolating and identifying various LAB strains from different Sicilian dairy environments. Twenty strains were selected based on their ability to produce antimicrobial substances, indicating their potential to inhibit the growth of harmful bacteria. These strains represented a diverse range of LAB species, each with its unique characteristics and potential contributions to cheese production.

Researchers tested the selected LAB strains against eight different strains of Listeria monocytogenes known to cause foodborne illness. The goal was to determine which LAB strains were most effective at inhibiting Listeria growth. The antimicrobial activity was assessed using various methods, including the spot-on-the-lawn method and the well diffusion assay (WDA). These tests helped to quantify the inhibitory effects of the LAB strains and identify those with the strongest anti-Listeria potential.

Spot-on-the-lawn method: A simple technique where LAB strains are spotted onto a Petri dish covered with a layer of Listeria bacteria. The presence of an inhibition zone around the LAB colony indicates its ability to inhibit Listeria growth.
Well diffusion assay (WDA): A more quantitative method where wells are created in an agar plate, filled with LAB culture supernatants, and then inoculated with Listeria. The diameter of the clear zone around the well indicates the extent of Listeria inhibition.

To confirm that the inhibitory substances produced by LAB were proteinaceous in nature (bacteriocins), researchers treated the culture supernatants with proteolytic enzymes. These enzymes break down proteins, and if the inhibitory activity was eliminated after enzyme treatment, it confirmed that the active compounds were indeed bacteriocins. The LAB strains were then tested in single and multi-strain combinations to assess their effectiveness in cheese production. A mix of Lactococcus lactis, Lactobacillus rhamnosus, and Enterococcus faecium was used to preserve the sensory profile and structural characteristics of each cheese.

The Future of Food Safety: Natural Solutions for a Healthier World

This research highlights the potential of natural solutions, like lactic acid bacteria, in enhancing food safety and quality. By understanding and harnessing the power of these beneficial microorganisms, we can develop innovative strategies to combat foodborne pathogens and create safer, more delicious foods. The traditional practices of Sicilian cheesemakers offer valuable insights into the future of food safety, where natural solutions and scientific knowledge work together to protect consumers and preserve culinary heritage.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.4081/ijfs.2017.6191, Alternate LINK

Title: Anti-Listeria Activity Of Lactic Acid Bacteria In Two Traditional Sicilian Cheeses

Subject: Food Science

Journal: Italian Journal of Food Safety

Publisher: PAGEPress Publications

Authors: Maria Luisa Scatassa, Raimondo Gaglio, Cinzia Cardamone, Giusi Macaluso, Luigi Arcuri, Massimo Todaro, Isabella Mancuso

Published: 2017-01-24

Everything You Need To Know

What is Listeria monocytogenes, and why is it a concern in food production?

Listeria monocytogenes is a foodborne pathogen that poses a significant public health risk. It's particularly concerning because it can survive in harsh conditions such as acidic environments and low temperatures, making it difficult to control, especially in dairy products like cheese. This resilience can lead to serious infections, especially in vulnerable populations such as pregnant women, the elderly, and those with weakened immune systems, hence the need to find effective methods to eliminate it.

How do traditional Sicilian cheesemakers contribute to food safety using natural methods?

Traditional Sicilian cheesemakers have long used lactic acid bacteria (LAB) in the production of cheeses such as Pecorino Siciliano (PS) and Vastedda della valle del Belice (VB). These LAB naturally produce bacteriocins, antimicrobial substances that inhibit the growth of undesirable bacteria, including Listeria monocytogenes. This process, though not always understood scientifically until recently, has contributed to safer and more flavorful cheeses for centuries, representing a practical application of natural food safety techniques.

What are bacteriocins, and what role do they play in cheese safety?

Bacteriocins are antimicrobial substances produced by lactic acid bacteria (LAB). In the context of cheese safety, these proteinaceous compounds inhibit the growth of harmful bacteria, including Listeria monocytogenes. The study mentioned in the text confirmed the proteinaceous nature of these inhibitory substances by using proteolytic enzymes, which eliminated the inhibitory activity, thereby confirming that the active compounds were bacteriocins. These bacteriocins help in creating safer cheese products by preventing the proliferation of foodborne pathogens.

Can you explain the methods used to test the effectiveness of lactic acid bacteria (LAB) against Listeria?

The research employed several methods to assess the anti-Listeria potential of LAB strains. The first method used was the spot-on-the-lawn method, where LAB strains were spotted onto a Petri dish covered with Listeria. The presence of an inhibition zone around the LAB colony indicated the ability of the LAB to inhibit Listeria growth. The second method was the well diffusion assay (WDA), which is a more quantitative approach. Wells were created in an agar plate, filled with LAB culture supernatants, and then inoculated with Listeria. The diameter of the clear zone around the well indicated the extent of Listeria inhibition. These methods helped researchers identify LAB strains with the strongest anti-Listeria potential.

What are the implications of using a mix of Lactococcus lactis, Lactobacillus rhamnosus, and Enterococcus faecium in cheese production?

The utilization of a combination of Lactococcus lactis, Lactobacillus rhamnosus, and Enterococcus faecium in cheese production is aimed at preserving the sensory profile and structural characteristics of the cheese. This multi-strain approach leverages the unique benefits of each LAB species. These LAB strains were selected because they could inhibit Listeria. By using these bacteria combinations, cheesemakers can balance food safety with maintaining the traditional taste and texture of cheeses like Pecorino Siciliano and Vastedda della valle del Belice. This method ensures the product is both safe from pathogens and true to its original form.