Enhancing survival of Bifidobacterium spp. in yoghurt through oxidative stress adaptation

Background Bifidobacterium spp. are widely recognised probiotic bacteria with well‐documented health benefits associated with their incorporation into foods. Despite these benefits, maintaining their viability in oxygen‐rich environments like yoghurt poses substantial challenges. Aim This study examined the impact of oxidative stress adaptation on the viability, fermentation characteristics and physicochemical properties of Bifidobacterium spp. during yoghurt production and shelf‐life at 4°C. Methods Oxidative (H 2 O 2 ) stress‐adapted and unadapted strains of Bifidobacterium bifidum, B. breve and B. animalis subsp. animalis, 6–7 log cfu/mL, were incorporated during yoghurt fermentation. Two independent yoghurt batches were produced for each treatment combination, with two replicates analysed per batch. Viability (via plate counts and PMAxx‐qPCR) and physicochemical properties were monitored over 28 days at 4°C. Major Findings Stress adaptation enhanced B. bifidum survival during fermentation by 1.0 log cfu/g compared with unadapted strains ( P < 0.0001), with B. breve showing similar improvement. Although adaptation initially improved survival, this advantage diminished throughout shelf‐life in both species. B. animalis remained stable. The plate count method showed a decline of B. bifidum and B. breve populations, while the PMAxx‐qPCR method detected a significantly higher level of viable cells ( P < 0.05) in the yoghurt. Scientific Implications Oxidative stress adaptation may enhance Bifidobacterium spp. viability and the functional value of probiotic yoghurt.