Ioannis S Boziaris1, Anastasios P Stamatiou, George-John E Nychas. 1. Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fitokou Street, GR-38446 Nea Ionia, Volos, Greece. boziaris@uth.gr
Abstract
BACKGROUND: Fresh fish and seafoods are very perishable products mainly owing to microbial activity of specific spoilage micro-organisms. Application of hurdle technology leads to a variety of processed products with extended shelf life. In this study, sensory evaluation and microbiological analysis were carried out on 17 processed seafood products stored at 4 °C to determine their shelf life and the predominant spoilage micro-organisms. RESULTS: Shelf life determined by sensory analysis varied from 66 to 180 days depending on the product. The cause of spoilage for most of the products was the development of off-flavours/off-odours, while two products were rejected owing to oil discolouration. Pseudomonads were in most cases below detection limit. H₂S-producing bacteria, Brochothrix thermosphacta and Enterobacteriaceae were below detection limit throughout the experiment. The predominant spoilage micro-organisms were lactic acid bacteria and yeasts. Hygiene indicators such as Staphylococcus spp. and total coliforms were also below detection limit in all samples. CONCLUSION: Primarily the initial pH and secondarily the NaCl content determined shelf life duration. Under the applied conditions, lactic acid bacteria and yeasts predominated. The contribution of chemical oxidation and/or autolysis to spoilage and shelf life might be important for most of the products.
BACKGROUND: Fresh fish and seafoods are very perishable products mainly owing to microbial activity of specific spoilage micro-organisms. Application of hurdle technology leads to a variety of processed products with extended shelf life. In this study, sensory evaluation and microbiological analysis were carried out on 17 processed seafood products stored at 4 °C to determine their shelf life and the predominant spoilage micro-organisms. RESULTS: Shelf life determined by sensory analysis varied from 66 to 180 days depending on the product. The cause of spoilage for most of the products was the development of off-flavours/off-odours, while two products were rejected owing to oil discolouration. Pseudomonads were in most cases below detection limit. H₂S-producing bacteria, Brochothrix thermosphacta and Enterobacteriaceae were below detection limit throughout the experiment. The predominant spoilage micro-organisms were lactic acid bacteria and yeasts. Hygiene indicators such as Staphylococcus spp. and total coliforms were also below detection limit in all samples. CONCLUSION: Primarily the initial pH and secondarily the NaCl content determined shelf life duration. Under the applied conditions, lactic acid bacteria and yeasts predominated. The contribution of chemical oxidation and/or autolysis to spoilage and shelf life might be important for most of the products.