Research

Investigation of intestinal ecosystems with probiotics and prebiotics

Current & Past Funding

National Institutes of Health
California Dairy Resarch Foundation
USDA NIFA AFRI
National Institutes of Health
American Diabetes Association

Pre- and Probiotics are added to foods and beverages to confer health benefits in the human digestive tract. We are employing these dietary components to study the interactions between bacteria and the host which influence immune function and digestive health. Probiotic Bifidobacterium and lactic acid bacteria (LAB) in the genus Lactobacillus are being investigated for their adaptations to plant and dairy matrices to understand how food carriers and host diet effect intestinal persistence and interactions with intestinal epithelial and immune cells and the native microbial communities residing in the gut. Our studies on prebiotic ingredients are establishing the effects of fermentable fibers on intestinal community composition, including Lactobacillus and Bifidobacterium species, and the mechanisms by which those microorganisms can influence health.

Lactic acid bacteria (LAB) associated with plants and plant-based fermentations

Current & Past Funding

Fermented food processors
California Department of Food & Agriculture
USDA AFRI NIFA

LAB are essential for the production of many fermented plant-based food and beverages. These fermented foods are important components of the diet in many human cultures worldwide. At present, the niche specificity of LAB strains for growth and survival on living plant tissues is not well understood. In our lab, we study the specific adaptations of LAB to plants and the microbial community succession events which occur during plant tissue fermentations. This knowledge will result in improved management of food, feed, and fuel fermentations and establish the relationships between LAB integral to our food supplies and the LAB colonists of the human gut.

Promoting food safety and quality through microbial community management

Current & Past Funding

Center for Produce Safety
USDA AFRI NIFA
California Almond Board
UC Davis RISE program

Food borne illness is associated with the consumption of fresh fruits, vegetables and nuts contaminated with human pathogens. We are studying the effects of the native microbiota inhabiting fresh produce on human pathogens which might come into contact with those plants in the field. These studies also include molecular genetic analysis of specific lactic acid bacteria (LAB) which serve as potential antagonists of human pathogens or are otherwise important for quality control in food industries.

Similarly we are applying modern high-throughput methods to identify and quantify the bacteria in dairy processing chains for rapid and accurate assessments of milk quality and safety.

Current & Past Funding: California Dairy Research Foundation

Lab News

Gordon Conference on lactic acid bacteria

The first ever Gordon Research Conference on lactic acid bacteria was held in Ventura, CA from July 23 to 28, 2023. The conference was a fun week of interactive sessions and lots of time for networking and making new friends pursuing research on this fascinating group of bacteria. We had over 120 participants from nearly all corners of the world. The meeting included excellent speakers and impressive posters on a wide-range of topics including lactic acid bacteria metabolism, cell surface composition, and phages, to fermented foods and uses of these bacteria in medicine and engineering.

Be on the lookout for the next meeting expected in 2025! https://www.grc.org/lactic-acid-bacteria-biology-symbioses-and-applications-conference/2023/

New paper on the benefits of friendly microbes in our diets

Our collaborative ISAPP group found that foods with higher microbial concentrations are associated with modest health improvements across a range of outcomes. This paper used NHANES participants’ reported food intake to quantify the food they ate that contained medium or high levels of microbes. Then they determined how these intakes correlated with various markers of health such as blood pressure and weight. We found that increased consumption of live microbes in the diet was linked with multiple measurements of better health: more favorable blood pressure, better blood glucose and insulin, lower inflammation, as well as lower waist circumference and body mass index. This established that those who consumed higher quantities of live dietary microbes showed tangible, if modest, health benefits.

https://doi.org/10.1016/j.tjnut.2023.02.019

New paper on intraspecific diversity of L. plantarum

This published in Applied Environmental Microbiology shows how intraspecies interactions in food fermentations are dependent on metal cation availabilty. We are excited to share these findings because they provide new insight on the ecological interactions and nutritional requirements of microbes in food fermentations which can be used to improve the quality and consistency of those foods.

Glory Bui wins ISAPP SFA poster award

Glory Bui (PhD student MGG) received the honor of a coveted poster award at the annual International Scientific Association of Probiotics and Prebiotics (ISAPP) meeting in Sitges, Spain. The award was given to two students by the Student Fellows Association (SFA). Congratulations to Glory on her excellent research and presentation on diffusible factors made by L. casei in milk which improve intestinal epithelial barrier function.

New project to prevent the spread of antimicrobial resistance

We are excited to share the news that we are launching a new project to reduce antibiotic use and risk of antimicrobial resistance in pig production. This $21.2 million, 5-year PIG-PARADIGM project is funded by the Novo Nordisk Foundation. Our lab is teaming up with other researchers at UC Davis and at universities in Denmark and the Netherlands. We will be studying how to prevent the need for antibiotics during pig weaning by improving digestive tract resilience through the gut microbiome. More information about our plans can be found here and here.