In an evolving health landscape, emerging research continues to highlight concerns that could impact everyday wellbeing. Here’s the key update you should know about:
Researchers show how advanced sequencing and natural compounds are shaping the ongoing fight against deadly foodborne diseases, from Listeria hiding in biofilms to frankincense smoke killing harmful microbes.
Study: Zoonotic Pathogens in Food: New Advances and Editorial Insights. Image credit: Corona Borealis Studio/Shutterstock.com
A recent editorial special issue published in Foods highlights the current challenges and recent advances in detecting and controlling zoonotic pathogens in food and food-related environments.
Food-borne illness and its consequences
Approximately 600 million people develop foodborne illness after consuming contaminated food, among whom roughly 420,000 die. Children below five years of age account for nearly 30% of all fatalities. Therefore, food contamination is considered a significant public health threat.
Individuals from low- and middle-income countries develop foodborne illness due to improper food storage, poor hygiene practices, infrastructural deficiencies, and inconsistent regulatory enforcement. The increasing emergence of multidrug-resistant foodborne pathogens has triggered the need for surveillance, consumer education, and antimicrobial assessments.
Pathogens, including Escherichia coli, Salmonella spp., Listeria monocytogenes, and Campylobacter spp., cause food-borne illness with wide-ranging symptoms from mild gastrointestinal distress to more severe, life-threatening conditions. Viral agents, including Norovirus and Hepatitis A virus, are also significant threats to food safety. Some zoonotic pathogens significantly affect vulnerable populations, including infants, toddlers, older adults, and immunocompromised individuals. Besides bacteria, parasites (Giardia lamblia and Entamoeba histolytica, and Taenia spp.) and fungi (e.g., Penicillium, Claviceps, Aspergillus, and Fusarium) are pathogenic to humans and can cause food-related illnesses.
Physiological and molecular adaptation of foodborne pathogens
The editorial summarizes studies in which researchers have explored foodborne pathogens’ physiological and molecular adaptation under environmental stress conditions. In one study cited, researchers used 1D electrophoresis, 2D-PAGE, and tandem mass spectrometry to identify proteome modulation in L. monocytogenes ST7 in response to highly acidic and saline conditions and extremely low temperatures. This study highlighted condition-specific expression of virulence factors, such as Internalin A and Listeriolysin O.
Stress responses and protein expression patterns vary depending on environmental factors related to food storage and production. Future research should incorporate bioinformatic tools, such as VirulentPred and Vaxijen v.2.0, to characterize proteins in terms of their virulence and immunogenic potential. Gene editing tools, including CRISPR-Cas-assisted recombineering systems, can be used for targeted gene manipulation.
Recent studies have indicated the strain-specific adaptation and unique pathogenic potential, thereby underscoring the importance of combining proteomic and transcriptomic data to identify virulence markers beyond genomic predictions.
The higher emergence of atypical L. monocytogenes (aLm) strains than previous estimations could be attributed to environmental and processing factors in both animal- and plant-based food chains. This strain exhibits a distinct phenotypic and genotypic profile, including a lack of hemolysis, which correlates with virulence genes (e.g., prfA, inlB, and mpl). In the future, researchers could use phenotypic fingerprinting to distinguish aLM from both classical L. monocytogenes and other Listeria species. The aLM strains exhibited higher antibiotic resistance, which raised concerns about them being potential unknown reservoirs of resistance and pathogenicity.
The editorial also notes that biofilm formation on surfaces such as stainless steel, glass, and plastics plays a crucial role in the persistence of L. monocytogenes in food processing environments, complicating cleaning and disinfection efforts.
Detection Technologies
Since standard ISO detection methods may be ineffective in determining aLM strains, researchers strongly suggest using advanced tools, such as MALDI-TOF and genomic sequencing. These techniques would enable the detection of horizontal gene transfer to more virulent L. monocytogenes populations.
Whole-genome sequencing (WGS) has been recently used to isolate L. monocytogenes strains from ready-to-eat refrigerated foods. This study demonstrated the potential of the WGS technique to accurately identify plasmid elements, resistance determinants, such as brcBC and qacJ genes, and mobile genetic elements associated with environmental persistence. Therefore, WGS can improve surveillance and food safety risk assessment.
Long-read sequencing using the Oxford Nanopore MinION has recently been applied to detect Shiga toxin-producing E. coli (STEC) directly from ground beef samples. This method enables the identification of virulent genes within a few hours in pure cultures and enriched food samples. The use of the long-read sequencing method can not only reduce manual labour but also significantly decrease diagnostic time in routine food safety testing.
Foodomics is a multidisciplinary field that combines genomics, proteomics, lipidomics, metabolomics, and bioinformatics to assess food quality and microbiological safety across the entire supply chain. The editorial highlights that genomics also supports breeding programs and food authentication, proteomics and metabolomics help optimize nutrition and safety profiles in animal-derived products, and lipidomics aids functional food development. Advanced computational methods such as machine learning are increasingly needed to integrate these omics datasets.
Gas chromatography-mass spectrometry (GC-MS) is widely used to detect microbial food spoilage and identify toxic compounds formed in various food products, including fish, honey, dairy products, and wine. However, high implementation costs and the need for specialized infrastructure inhibit the widespread adoption of these advanced methods for early detection of foodborne pathogens.
Exploring the antimicrobial properties of natural compounds
Researchers have identified antimicrobial activities in natural compounds, such as essential oils. For example, GC-MS is used to identify monoterpenes and sesquiterpenes with antimicrobial activity against Gram-positive and Gram-negative bacteria, yeasts, and molds.
Saccharomyces cerevisiae and Fusarium solani demonstrated high sensitivity to essential oils. Similarly, Staphylococcus aureus, E. coli, airborne molds, and yeasts were effectively eliminated by frankincense smoke, a natural sanitation agent. However, the inhalation of fine particulate matter can have adverse health effects. Encapsulated whey protein with cinnamaldehyde exhibited significant antimicrobial efficacy against Listeria innocua, E. coli, and S. cerevisiae populations.
In contrast, vanillin showed limited improvement with encapsulation. The study further used Gompertz and Weibull mathematical models to analyze microbial inactivation, highlighting the importance of predictive modelling in food preservation research.
The next step
The research in the Special issue highlighted the current challenges and emerging solutions in controlling zoonotic pathogens in the food sector. It also explored the potential of advanced techniques to identify microbial pathogens associated with foodborne diseases and novel antimicrobial agents derived from natural sources.
The editorial emphasizes the need for standardizing protocols, improving detection in complex environments, and integrating omics with antimicrobial strategies. Interdisciplinary collaboration among food technologists, microbiologists, bioinformaticians, and public health professionals is essential for developing effective interventions to treat foodborne illnesses.