Meet the Microbiologist

Xiaonan Lu, Ph.D., Professor and Ian & Jayne Munro Endowed Chair in Food Safety at McGill University, Tier-1 Canada Research Chair in Food Safety and Editor in Chief of ASM Food Microbiology, discusses bacterial dormancy in foodborne pathogens and the challenges it creates for detection and food safety. He highlights advances in genomics, nanosensors, single-cell analysis and AI, and shares his vision for the future of food microbiology research.

Understanding Bacterial Dormancy

Drawing from his own multidisciplinary training, Lu's lab brings together engineering, chemistry, genomics and molecular microbiology to better understand foodborne pathogens. Through technologies such as microfluidics, optical tweezers and single-cell RNA sequencing, his team studies bacterial dormancy, a survival strategy that allows pathogens to withstand environmental stressors (e.g., temperature changes, desiccation, sanitizers and others) and evade conventional detection methods. He shares emerging findings from experiments with Camplyobacter jejuni—one of the leading causes of contamination-induced diarrhea in humans—indicating that dormancy may involve an intermediate state between persister and viable-but-nonculturable (VBNC) cells.

Improving Food Safety Detection

Detecting pathogens in food is rarely straightforward, and it can be difficult to separate a signal from biological and chemical noise. Lu examines how complex food matrices, low pathogen levels and competing microbial communities can complicate recovery and testing efforts. He discusses promising approaches for improving detection, including antibody- or aptamer-based separation methods, selective molecular assays and the growing use of whole-genome sequencing to trace contamination sources.

The Future of Food Microbiology

Looking ahead, Lu explores how AI could help unlock insights from existing datasets, predict food shelf life from image analysis and potentially identify early signals of disease outbreaks. He also highlights opportunities to leverage microbes for healthier foods, reduced waste and more sustainable food systems, while emphasizing the importance of curiosity, collaboration and openness to new technologies.

About ASM Food Microbiology

As Editor in Chief, Lu shares the vision for ASM Food Microbiology as a dedicated home for food microbiology research. The journal encompasses topics ranging from food safety and fermentation to sustainability, beneficial microbes, AI and precision fermentation, providing a platform for both established and emerging areas of the field.

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Links for This Episode:

• Learn More About ASM Food Microbiology
• Take the MTM listener survey!

John Warhol, Ph.D., blends his Periodic Table of Microbes with rock music, movies, and state-microbe petitions to bring microbes' most unforgettable stories to light.

Watch this episode: https://www.youtube.com/watch?v=bZYEBfo4nHc

Stanley Malloy and Jack Gilbert unpack how AI tools are reshaping the microbial sciences—from genomics and microbial communities to manuscripts, peer review and publishing ethics—highlighting AI's power, potential and pitfalls for public trust in science.

Episode Links:

• JMBE Collection: Practical and Positive Uses of AI in STEM Education
• MtM Survey: asm.org/mtmsurvey

Glen McGugan, Ph.D., Director of ASM's Mechanism Discovery Unit, discusses how curiosity‑driven research—from parasite virulence to CRISPR and complex microbial systems—drives tomorrow's breakthroughs.

Ashley's Biggest Takeaways

• Mechanism discovery,encompasses all of the foundational basic research across the microbial sciences and is essential for all advances in microbial science.
• Many transformative technologies (e.g., CRISPR) originated from curiosity-driven, basic research rather than immediate practical goals.
• McGugan's experience as a Program Officer at NIH provided him with a broad perspective on the research pipeline, from basic science to clinical trials, and highlighted the importance of supporting early-career scientists.
• Developing therapeutics for parasitic diseases is particularly challenging due to complex life cycles and limited financial incentives for pharmaceutical companies; much of the progress relies on government and philanthropic funding.
• ASM's Mechanism Discovery Unit serves as a neutral hub to convene interdisciplinary stakeholders, foster collaboration, and advance fundamental research.
• Safeguarding future breakthroughs in the microbial sciences depends on the involvement of and connections between researchers, policymakers, funders and industry partners to close gaps between discovery, implementation and impact.

Andrea Prinzi, Ph.D., MPH, SM(ASCP), and Rodney Rohde, Ph.D.,SM(ASCP)CM, SVCM, trace how passion‑driven, nonlinear paths in clinical microbiology led them from hospital benches and public health labs to academia and industry leadership. Their stories converge on a shared mission: to use diagnostics, outcomes research and lived experience to make microbiology relevant, contextual and approachable for patients, policymakers and the broader public.

Links for This Episode:

• View Prinzi's ASM articles.
• View Rohde's ASM articles.
• Volunteer to write for ASM.
• Take the MTM listener survey!

Moon Nahm, M.D., professor emeritus at UAB Department of Medicine and Director of the World Health Organization's Pneumococcal Serology Reference Laboratory at UAB, discusses his career in pneumococcal immunology. From uncovering the WU2 reference strain and other hidden serotypes to pioneering Multiplexed Opsono-Phagocytosis Assay (MOPA) to measure the functional activity of anti-pneumococcal antibodies, Nahm's contributions have facilitated development of advanced vaccines with broader protection and accessibility.

Links for This Episode

• UAB Spotlight on Moon Nahm.
• Discovery and Characterization of Pneumococcal Serogroup 36 Capsule Subtypes, Serotypes 36A and 36B. Journal of Clinical Microbiology paper, March 27, 2003.
• A New Pneumococcal Capsule Type, 10D, is the 100th Serotype and Has a Large cpsFragment from an Oral Streptococcus. mBio, May 19, 2020.
• 50 years—and change. WashU Magazine.
• MTM Listener Survey

From leading R&D at a biotech startup company to conducting environmental monitoring for NASA, Veronica Garcia, Ph.D., Scientific Director of the ASM Applied and Environmental Microbiology unit shares how experiences throughout her career have informed her appreciation for microbes and their real-world applications. She also discusses how the ASM AEM unit will support scientists around the globe by fostering collaboration and advocating for scientific advancements in areas like climate change, water systems and food production.

Ashley's Biggest Takeaways

• Prior to her role as Scientific Director for ASM Applied and Environmental Microbiology unit, Garcia was Senior Director of R&D at Boost Biomes, a biotech startup focused on bio-pesticides and bio-fertilizers.
• Garcia's passion for microbiology began studying soil remediation at Texas A&M University.
• Seeing microbes under the microscope for the first time felt like discovering "another world," sparking a lifelong fascination with what microbes are and can do.
• Driven by a desire to see her science make an immediate impact, Garcia was drawn to industry after completing her Ph.D.
• At Boost Biomes, a biotech startup company, Veronica helped transform diverse microbial isolates into bio-pesticides, bio-fertilizers and bio-stimulants for agriculture and food. She progressed from bench scientist to senior Director of R&D, overseeing discovery, genomics, bioinformatics and product development, and learned the realities of scale-up, cost, regulation and end-user needs.
• She also monitored air, water and surfaces for the shuttle and ISS and NASA, ensuring astronaut safety by tracking microbial loads and potential pathogens.
• ASM is organizing around 3 scientific units, ASM Applied and Environmental Microbiology (AEM), ASM Health and ASM Mechanism Discovery.
• These units will equip researchers to translate discovery into impact while providing a forum to collectively shape the future of the field.
• The AEM unit provides the space and unique expertise for microbial scientists and partners to directly contribute to a healthier, more sustainable world through applied and environmental innovation and brings together experts whose work connects microbial processes to outcomes in ecosystems, infrastructure, food systems and planetary health.

Links For This Episode

• Learn More About ASM's Scientific Units.
• Join the Conversation on ASM Connect, our online community platform.
• Browse Volunteer Opportunities.
• Become an ASM Member.
• Take the MTM listener survey!

Marlene Belfort, Ph.D., a distinguished professor at the University at Albany and author of Mommy, Can Boys Also Be Doctors?, discusses her journey in science, balancing personal and professional life, the importance of fundamental research and the discovery of introns in bacteriophage.

Links for This Episode

• Mommy, Can Boys Also Be Doctors?: A Message to Young Scientists and Other Humans.

Episode Summary Sue Ishaq, Ph.D., Associate Professor of Microbiomes at the University of Maine, discusses how gut microbes transform seemingly inert plant compounds—like glucosinolates found in broccoli—into powerful anti-inflammatory agents such as sulforaphane. Her research dives into the fascinating interplay between diet, cooking methods and the diversity of the gut microbiota, revealing how these factors influence the body's ability to produce health-promoting molecules. Links for This Episode

• mSystems paper: Early life exposure to broccoli sprouts confers stronger protection against enterocolitis development in an immunological mouse model of inflammatory bowel disease.
• mSystems paper: Steamed broccoli sprouts alleviate DSS-induced inflammation and retain gut microbial biogeography in mice.
• Current Developments in Nutrition paper: Current knowledge on the preparation and benefits of cruciferous vegetables as relates to in vitro, in vivo, and clinical models of Inflammatory Bowel Disease.

Karl Matthews, Ph.D., Professor of Microbial Food Safety at Rutgers University, discusses ways to eliminate pathogens like Salmonella, E. coli O157:H7 and Listeria from fresh fruits and vegetables. He highlights the importance of preventative measures from farm to table, including the use of water antimicrobials, like chlorine, and photosensitizers, like curcumin.

Watch this episode: https://youtu.be/6Wkef9RyUVE

Ashley's Biggest Takeaways

• We consume billions of microorganisms in the food that we eat each day.
• Fresh fruits and vegetables that are not thermally processed are likely to carry a higher microbial load than cooked foods.
• Many of those microbes are not concerning to human health. However, when pathogens of human health concern are present, the food can become unsafe to eat.
• Scientists use many methods from pre-harvest through post-harvest to keep food free of human pathogens.
• Water antimicrobials, such as chlorine, and photodynamic inactivation using photosensitizers, such as curcumin, are 2 preventative measures that Matthews and colleagues are investigating.
• Curcumin is a natural chemical compound found in the turmeric plant. It is responsible for giving tumeric its yellow color.
• Curcumin is also a photosensitizer, meaning that it can absorb light energy and transfer it to another molecule to initiate chemical reactions that produce cytotoxic singlet oxygen.

Featured Quotes

When I look at [what makes fruits and vegetables safe to eat] as far as from a microbiological perspective, it's are they free of pathogens of human health concern? And so, we might think about organisms, such as Salmonella or the Shiga toxin producing E coli or Listeria. There are a number of processes and initiatives that are put into place, from the pre-harvest through post-harvest levels to try to ensure that the product is not contaminated with microorganisms of human health concern. Each day, we're consuming literally billions of microorganisms in the foods that we eat, and particularly the raw fruits and vegetables that we're eating that are not being thermally processed in any fashion by which you might reduce the microbial load. Oftentimes we think about the bacteria that might well be there. But we do know that there's viruses that could be present. There's certain type of protozoa that might be present. Many of us know of norovirus and the concerns associated with that particular pathogen. So, there's a multitude of microorganisms that might well be associated with fresh fruits and vegetables, but there's really a very limited number or types that are actually of concern from a human health standpoint. In my program, we're working on E. coli O157:H7, in particular. It's a certain serotype of E. coli, a diarrheagenic E. coli, what's also known as a Shiga toxin-producing E. coli. We work with Salmonella, and we work with Listeria monocytogenes, but there's other microorganisms, such as Campylobacter, Yersinia, Staphylococcus aureus. All of those types of pathogens can also be associated with foods—and different types of foods, at that—and be of concern to the general public—the consumer. If we look at a lot of the processing of foods that are taking place, not only here in the United States, but globally, many times, what will happen is they're utilizing some type of a water antimicrobial, and I stress that because, oftentimes, these antimicrobials are added to the water to control the microbial load in the water. So, ultimately, you're not basically putting on water and putting on a whole load of microorganisms along with it. And also, you can prevent cross contamination through that. Here in the U.S. and elsewhere, we'll often put additional chlorine into the water. So, let's say we're increasing the chlorine concentration to 20 parts per million, or 50 parts per million, or maybe in poultry processing, they're utilizing peracetic acid. These are 2 common antimicrobials that are being used. What we wanted to do is find out could we utilize some other types of methods that might well control microorganisms on the commodity itself? And that's where we started looking at photodynamic inactivation and coupling that with the use of a photosensitizer. And in this particular case, the photosensitizer we were using was curcumin. The reason for working with curcumin is that it's naturally used in foods as a food dye. It's also used as a flavoring agent, and so forth. So, it's there, and it's being used—not just in the U.S., but [also] globally. And we thought we would try to see if we utilize this compound, could we have an additive effect to it? If you apply certain wavelengths of light, you can inactivate microorganisms, but if you apply that wavelength to something like a photosensitizer type molecule (curcumin), you could generate singlet oxygen molecules. And those singlet oxygen molecules would act like little explosions on the cell membrane and basically blow it apart and, therefore, inactivate the organism. We looked at the ability of this to inactivate Listeria monocytogenes, Salmonella, as well as E. coli O157:H7, so these Shiga toxin-producing E. coli, and what we did indeed find is that it was very effective. We looked at it in comparison to peracetic acid use in the poultry industry, and we found it to be equivalent, at least to treatments that we were utilizing on poultry skin, with inactivation of the microorganisms, such as Listeria, on the poultry skin. So, it is really exciting.

Links for This Episode

• ​​​​​​Preventing Foodborne Outbreaks Starts in the Field.
• Influences of photosensitizer curcumin on microbial survival and physicochemical properties of chicken during storage.