The potential of using yoghurt as a delivery vehicle for microencapsulated Salmonella phage Felix O1 with alginate‐caseinate formulation

Background Antibiotic‐resistant pathogenic bacteria require alternative antimicrobial treatments, such as oral bacteriophage therapy. However, bacteriophages are sensitive to the harsh conditions of the gastrointestinal tract. Microencapsulating phages and utilising protective food matrices such as yoghurt could protect these phages and assist in successfully delivering them to the target intestine. Aim(s) This study aimed to evaluate the effect of adding the microencapsulated phage Felix O1 on the physicochemical and microbiological properties of yoghurt, the potential of yoghurt as a delivery vehicle for transferring microencapsulated phage Felix O1 to intestine and the release kinetics of bacteriophage from microcapsules under simulated in vitro gastrointestinal conditions. Methods The study analysed the yoghurt's physicochemical properties, the viability of yoghurt starter cultures, phage survival in simulated gastric fluid and release kinetics. All measurements were done in triplicate. The PROC GLM procedure of SAS, which involved two factors (samples and storage period) as class variables, was used to compare the titre of phage Felix O1 in SGF and SIF solutions. Sigmaplot 12 was used to model the release profile of phage Felix O1. Major Findings The addition of microencapsulated or free phages did not adversely affect the yoghurt's physicochemical properties or the viability of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus . The titre of free phage Felix O1 was not determined in yoghurt samples during exposure to the SGF solution on the 30th day of storage. The kinetic release of phage Felix O1 from microcapsules in the presence of yoghurt was of the diffusional type and correlates with the Korsmeyer–Peppas model. Industrial Implications Yoghurt serves as an effective and protective delivery matrix for microencapsulated bacteriophages during both storage and simulated digestion. This presents a promising approach for the dairy industry to develop functional fermented foods capable of safely transporting therapeutic phages to the gut to combat intestinal pathogens.