Abstract

Title: Biocompatibility of chitosan and Salmonella phages to be used as biomaterial in protective and edible films Authors: Dácil Rivera, Christopher Hamilton-West, Andrea Moreno Switt, Andrónico Neira-Carrillo Introduction: Salmonella is a widely distributed zoonotic pathogen that can be transmitted to humans as foodborne. At the global level the one that produces the largest number of outbreaks is S. Enteritidis. Different countries have approved the use of phages for use as a safe food additive in food. Usually been suggested that phages can be added by dipping or spraying or as a liquid to a large volume of food. These methods may not be adequate, as they could be wasteful and lead to the potential inactivation of the phage. Then the selection of the immobilization method and support depends on the nature of the bioactive material and on the application itself. Chitosan, a natural and biodegradable biopolymer, with antimicrobial activity but there aren´t studies that demonstrate the biocompatibility between chitosan and bacteriophages, although it is used to encapsulate of phage. Purpose: The aim of this work was to evaluate the biocompatibility of chitosan and generate chitosan films with reducing effect against S. Enteritidis. Methods: A purified stock of a cocktail of 5 phage isolate of S. Enteritidis with wide host range was obtained by using polyethyleneglycol precipitation and successive centrifugation and filtration passages. Medium molecular weight chitosan with 75-85% degree of deacetylation and 200-800 cps of viscosity was used. To achieve this goal different dilutions of phage and chitosan concentration at 1 and 2% was performed. Were tested using the spot test in Salmonella strain.
 Subsequently, 1% and 2% chitosan films immobilized on surface were dried at 30ºC by the solvent evaporation technique. The assays were performed in duplicate considering a negative control. Results: Biocompatibility of chitosan and Salmonella phages was tested. And it was proved that 2% chitosan films were more effective for the reduction of Salmonella, using S. Enteritidis model. Significance: Here in we describe the preparation of chitosan film, and the evaluation of the in vitro biocompatibility of chitosan and Salmonella phages and consequentially their capacity for the reduction Salmonella by using S. Enteritidis as model. This easy-way method for producing biofilm of chitosan could be represent a key strategy to control or use as suitable method for leading the potential inactivation of Salmonella or other interested phage.