Whey protein improves survival and release characteristics of bacteriophage Felix O1 encapsulated in alginate microspheres

Bacterial contamination is a major cause of food poisoning in humans worldwide. Phage therapy is a potential alternative to antibiotics in food animal production. Gastric acidity has been shown to compromise the viability of phage in vitro, hence, may affect the effectiveness of the phage treatment. Microencapsulation of bacteriophage in alginate microspheres protected phage against gastric acids; however, the release rate of phage was too slow when applied in chicks. The current study investigated the in vitro protection and release characteristics of alginate-whey protein microspheres (AWM) containing phage Felix O1 prepared by an extrusion method. Free phage was completely inactivated within minutes in simulated gastric fluid (SGF) at pH 2.0 and pH 2.5, while phage encapsulated in AWM mostly retained their viability after 2.0 h incubation. Encapsulated phage was completely released from the AWM in simulated intestinal fluid (SIF) within 3 h. Moreover, addition of maltodextrin to the encapsulation formula improved phage stability during air drying and storage. Our results show that addition of whey to alginate microsphere improved phage protection against acidic conditions and accelerated the release rate in SIF. AWM could be more suitable for oral phage therapy in chickens. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.