Mon, 2012-11-19 15:12 | 
Abstract
The purpose of the PhD thesis is to study the identity of the dominant spoilage microorganisms, their ability to produce metabolites that causing spoilage, the interaction among spoilage microorganisms and the pathogen Listeria monocytogenes and the effect of antimicrobial adjuncts on safety and quality of fish products under storage at various temperature and atmosphere conditions.
Initially, the spoilage profile of sea bream and sea bream fillets under different temperature conditions (0, 5, 15oC) and atmosphere (air and MAP) was investigated. The microbiota was studied by employing classical and molecular (culture dependent and culture independent) techniques. In the molecular-culture dependent techniques, bacterial isolates from the plates were identified by the 16S rRNA gene analysis and sequencing, while in the molecular culture independent techniques, prokaryotic DNA obtained directly from the fish flesh was determined by the gene 16S rRNA analysis, cloning and sequencing. Metabolic products (total volatile nitrogen, trimethylamine, biogenic amines and volatile metabolites) analysis was performed by using not only classical chemical analysis but also modern equipment such as HPLC and SPME GC-MS to evaluate the potential chemical indicators of fish deterioration.
Additionally, the fate of Listeria monocytogenes alone or in co-culture with the main spoilage microorganisms was studied using model fish juice agar substrate under air and MAP at 5oC. Finally, the fate of spoilage microbiota and Listeria monocytogenes was studied in presence of citrates as antimicrobial compounds.
