Encapsulation of SE-P47 phage specific to Salmonella Enteritidis and evaluation of its stability

This study was conducted to encapsulate the bacteriophage SE-P47 target to Salmonella Enteritidis by extrusion method and to examine its stability. Screening and optimization of effective factors in the encapsulation process were performed using fractional factorial design and face-centered central composite design, respectively. The optimum Na-alginate concentration and the ratio of coating material to phage for the encapsulation of SE-P47 phage were 1.5% (v/v) and 2:1, respectively. At the optimum encapsulation point, the highest encapsulation efficiency (98.52%), smallest capsule size (1.28 mm), and highest phage titer were achieved. When exposed to heat treatment at 80°C for 30 min, pH 2 and simulated gastric fluid (pH 2.0) for 120 min, the encapsulated phage maintained almost its stability, but the free (non-encapsulated) phage almost lost its activity. Phage release from beads in simulated intestinal fluid reached 100% in 4 h. In addition, free and encapsulated phage completely maintained their activity for 12 months at 4 and 25°C. The Salmonella phage encapsulated in this study exhibits high stability in harsh conditions. Thus, this encapsulated phage has the potential to be used as a biocontrol agent or therapeutic purposes in the food chain.