Thomashoff, Ursula LouiseSibanda, ThulaniBuys, E.M. (Elna Maria)2026-04-242026-04-242026-01Thomashoff, U.L., Sibanda, T. and Buys, E.M. (2026), Enhancing survival of Bifidobacterium spp. in yoghurt through oxidative stress adaptation. International Journal of Dairy Technology, 79: e70093: 1-14. https://doi.org/10.1111/1471-0307.70093.1364-727X (print)1471-0307 (online)10.1111/1471-0307.70093http://hdl.handle.net/2263/109765DATA AVAILABILITY STATEMENT : The data that support the findings of this study are available from the corresponding author upon reasonable request. SUPPLEMENTARY MATERIAL : Figure S1 (a) Melt curves showing primer specificity and relative amplicon quantities of serially diluted (100–107) Bifidobacterium spp. DNA and the resultant standard curve. (b) Standard curve of PMAxx-qPCR assay created and used for determining linear dynamic range (LDR), efficiency (E), and slope (K) for B. animalis subsp. animalis ATCC25527. Each point represents the mean ± standard deviation of CT values (n = 2).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 (H2O2) 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.en© 2026 The Author(s). International Journal of Dairy Technology published by John Wiley & Sons Ltd on behalf of Society of Dairy Technology. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License.Bifidobacterium spp.ProbioticPMAxx-qPCRViabilityOxidative stress adaptationYoghurtArticle