Researchers at Nofima developed a faster method to detect Listeria monocytogenes in food products, which is a significant challenge for the food industry due to its ability to survive in long-shelf-life products and its high mortality rate in humans. Using a handheld sequencing device (MinION), they can now detect Listeria in just four hours, 20 hours faster than traditional methods. This approach not only detects Listeria but also other microorganisms, offering a comprehensive view of the microbiological environment in food production. The quicker results could improve food safety and prevent human disease by allowing timely countermeasures.
Listeria monocytogenes poses a significant challenge to the Norwegian food industry, with extensive resources dedicated to controlling it. The bacterium is commonly found in food processing environments, where it can build reservoirs and contaminate products. It thrives in cold-stored foods that aren’t heated before consumption. Listeria can cause listeriosis, a serious disease with a 20-30% mortality rate, especially affecting the elderly, pregnant individuals, and those with weakened immune systems. Detecting and monitoring the bacterium in food processing environments is crucial to prevent contamination.
This study examined the growth and population dynamics of seven Listeria monocytogenes strains (with different sequence types) during enrichment, both with and without background microbiota. The researchers found that without background microbiota, some strains became more abundant in the later stages of enrichment, while coenrichment with microbiota led to more stable population dynamics. Using quasimetagenomic sequencing, they were able to detect Listeria and its strain diversity after just 4 hours of enrichment with both Oxford Nanopore and Illumina MiSeq sequencing methods. The MiSeq data also allowed prediction of co-occurring Listeria strains.
The rapid sequencing method developed by Nofima researchers offers significant potential for the Norwegian food industry, providing quick results that are crucial for modern food production. Traditional methods are often too slow for fast-paced environments. The next step is to test the method with real samples from the industry. The new sequencing technology could improve proactive measures against Listeria, helping to prevent contamination, food recalls, financial losses, and cases of listeriosis.
Extracted from Research Article “Surveillance of Listeria monocytogenes: Early Detection, Population Dynamics, and Quasimetagenomic Sequencing during Selective Enrichment”
published in the scientific journal Applied and Environmental Microbiology – 24 November 2021.
Keywords
Nofima, Listeria monocytogenes, food products, long-shelf-life, mortality rate, handheld sequencing, MinION, detection, microorganisms, microbiological environment, food production, food safety, disease prevention, food processing, reservoirs, contamination, cold-stored foods, listeriosis, weakened immune systems, sequence types, background microbiota, population dynamics, quasimetagenomic sequencing, Oxford Nanopore, Illumina MiSeq, strain diversity, sequencing technology, proactive measures, contamination prevention