Determination of the efficacy of encapsulated phages in the biocontrol of Salmonella Enteritidis and evaluation of use as a biopreservative in milk

The aim of this thesis is to encapsulate the SE-P47 bacteriophage specific to S. Enteritidis and investigate the potential uses of the encapsulated phage at different stages of the food chain. Two encapsulation techniques, extrusion and spray drying, were used and the encapsulation process was optimized by the extrusion method. It was determined that alginate beads produced by extrusion method had higher phage titers. The phage encapsulated under optimum conditions exhibited higher stability than free phage samples at different temperatures and pH values, and in simulated gastric fluid. The encapsulated and free-form phage samples stored at 4 and 25°C for 12 months maintained their viability. The release of phage from alginate beads was determined in simulated intestinal fluid and semi-skimmed milk, resulting in significant reductions in the counts of S. Enteritidis. The results show that SE-P47 phage encapsulated with alginate by extrusion method has the potential to be used as a therapeutic agent in animals or as a bioprotective agent in foods in the food chain.