Raw plant foods: a link in the environment-to-gut microbiome continuum

Abstract:
This research investigated how irrigation water microbiomes impact raw plant food microbiomes and persist throughout digestion. One-off irrigation events were simulated in a cut spinach model system using environmental runoff spiked with pathogens (E. coli 0157 and S. Typhimurium). Irrigation microbiomes significantly altered spinach microbiomes, with effects persisting beyond 10 days’ refrigerated storage. Spinach microbiomes with higher a-diversity and bacterial loads showed reduced persistence of water-derived microbiota. Simulated human digestion of irrigated spinach revealed a substantial digestion-resistant microbiome (~77% of pre-digested ASVs persisted), of which ~8% was irrigation-derived (SourceTracker). This finding supports the notion of environment-food-gut microbiome transmission.Pathogen concentrations were unimpacted by refrigeration or digestion (p > 0.05), reinforcing the need to reduce contamination for improved food safety.

Speaker:
Dr Penny Galbraith, CERC Postdoctoral Fellow, Agriculture and Food, CSIRO

Biography:
Penelope is a postdoctoral fellow in the Microbiomes for One System Health team at CSIRO (Australia). Her interests encompass microbial ecology, food systems microbiology, environmental science and One Health. She completed her PhD at Monash University (Civil Engineering, 2021) where she investigated vegetation and soil microbiomes for faecal pathogen inactivation in nature-based water treatment systems. At CSIRO, she researches how environmental microbiomes, such as those in irrigation water, influence fresh produce microbiomes and persist through digestion. Ultimately, she aims to advance innovative, microbiome-informed solutions that enhance food safety, industry practices, and both human and environmental health.