During a 7-year tenure at Massey University, New Zealand, he switched to working on commensal bacteria, applying the tools he previously used to study pathogens. He is a globally recognized leader in the field of Lactobacillus genomics, and he co-ordinated the ELDERMET project, a seminal study on the interaction between the diet and gut microbiome in older people. He also led the microbiome analysis for the EU project NuAge that showed that a Mediterranean diet delayed onset of frailty by improving the microbiome. He is a scientific advocate for Sustainability and environmental conservation, from native honey bees to wild Atlantic salmon. He was recently listed in the top 1% of highly cited scientists by Clarivate.