Effect of chitosan-rosemary coating on Salmonella typhimurium and E.coli O157H7 in turkey fillets during refrigerated storage

Due to increased attention and nutritional importance of turkey meat between consumers, researchers are looking for new ways in order to improve its shelf-life. Furthermore, in recent decades, consumer demands for healthier foods (without common chemical preservatives) have been increased. The aim of this study was to evaluate simultaneous effect of chitosan coating and rosemary essence on indicator bacteria including Salmonellatyphimurium (S. typhimurium)and E.coliO157:H7 in turkey meat fillets during refrigerated storage. For this purpose turkey fillets inoculated with 106 CFU/g S. typhimurium and Escherichia coli O157:H7. Then, all of inoculated fillets divided into 3 groups; without coating (control), treated with 1% acetic acid and suspended in chitosan solution containing 1% rosemary essence. All samples were kept at refrigerated temperature for 15 days. Bacterial count of S. typhimurium and Escherichia coli O157:H7 was performed at 3 day intervals (0, 3, 6, 9, 12, 15 days). Chemical tests which related to chemical spoilage and quality control of turkey fillets including pH and thiobarbituric acid (TBA) were evaluated at 3 day intervals (0, 3, 6, 9, 12, 15 days). The results indicated that the chitosan-rosemary coating has the significant effect (P<0.05) on decrease of bacterial load of S. typhimurium and E.coli O157:H7. Also, suspended samples in chitosan containing rosemary essence have fewer pH and TBA during storage than other groups.