While we are often exposed to bacteria in our food which could cause food poisoning, we don't always become ill -- why should this be so?
Professor Colin Hill, who is presenting his work at the Society for General Microbiology's autumn meeting in Nottingham, UK today, describes how bacteria use different tricks to aid their survival inside the body, helping to explain why food poisoning can be so unpredictable.
One of the biggest challenges faced by foodborne bacteria is acid. Acidic conditions, particularly in the stomach and in the gut will kill most microbes found in contaminated food.
Hill's group at University College Cork has revealed that Listeria bacteria, which may be found in soft cheeses and chilled ready-to-eat products, can overcome harsh acidic conditions by exploiting key food ingredients. Listeria that survive are able to cause serious and sometimes fatal infections, particularly in the elderly and pregnant women.
Certain food constituents such as the amino acid, glutamate, can help the bacteria neutralize acid, allowing the bacteria to pass through the stomach unscathed. Hill explains the significance of this: "People who consume foods that are contaminated with Listeria and are also high in glutamate, such as soft cheese or meat products, have a higher chance of developing serious infection than someone eating the same quantity of bacteria in a low-glutamate food," he said. "Of course this is further complicated by the fact that a contaminated, low-glutamate food could be eaten in combination with a high-glutamate food such as tomato juice, which could also increase the risk of infection."
Listeria can also take advantage of food processing and storage conditions to help them survive. "Bacteria that are exposed to low pH before entering the body may adapt to become more acid-tolerant and therefore better equipped to deal with acidic conditions in the body. For example, Listeria contaminating naturally acidic foods such as cheese may be more likely to cause infection than Listeria carried at a more neutral pH in water.
Hill explains how his group's work could help reduce the incidence of Listeria infections. "The number of cases of listeriosis has nearly doubled in the last decade in Europe. This is because the bacterium is so good at overcoming the challenges it faces in food and in the body," he said. "Our studies show that consuming Listeria in one food may be quite safe, while eating the same amount in another food might be lethal. By understanding the role of the food matrix we may be able to identify and eliminate high-risk foods from the diet of susceptible people."
Â
Â
Stay prepared and protected with Infection Control Today's newsletter, delivering essential updates, best practices, and expert insights for infection preventionists.
Reducing Hidden Risks: Why Sharps Injuries Still Go Unreported
July 18th 2025Despite being a well-known occupational hazard, sharps injuries continue to occur in health care facilities and are often underreported, underestimated, and inadequately addressed. A recent interview with sharps safety advocate Amanda Heitman, BSN, RN, CNOR, a perioperative educational consultant, reveals why change is overdue and what new tools and guidance can help.
New Study Explores Oral Vancomycin to Prevent C difficile Recurrence, But Questions Remain
July 17th 2025A new clinical trial explores the use of low-dose oral vancomycin to prevent Clostridioides difficile recurrence in high-risk patients taking antibiotics. While the data suggest a possible benefit, the findings stop short of statistical significance and raise red flags about vancomycin-resistant Enterococcus (VRE), underscoring the delicate balance between prevention and antimicrobial stewardship.
What Lies Beneath: Why Borescopes Are Essential for Verifying Surgical Instrument Cleanliness
July 16th 2025Despite their smooth, polished exteriors, surgical instruments often harbor dangerous contaminants deep inside their lumens. At the HSPA25 and APIC25 conferences, Cori L. Ofstead, MSPH, and her colleagues revealed why borescopes are an indispensable tool for sterile processing teams, offering the only reliable way to verify internal cleanliness and improve sterile processing effectiveness to prevent patient harm.
The Next Frontier in Infection Control: AI-Driven Operating Rooms
Published: July 15th 2025 | Updated: July 15th 2025Discover how AI-powered sensors, smart surveillance, and advanced analytics are revolutionizing infection prevention in the OR. Herman DeBoard, PhD, discusses how these technologies safeguard sterile fields, reduce SSIs, and help hospitals balance operational efficiency with patient safety.
Targeting Uncertainty: Why Pregnancy May Be the Best Time to Build Vaccine Confidence
July 15th 2025New national survey data reveal high uncertainty among pregnant individuals—especially first-time parents—about vaccinating their future children, underscoring the value of proactive engagement to strengthen infection prevention.