| Title: | Evaluation of spoilage potential and volatile metabolites production by Shewanella baltica isolated from modified atmosphere packaged live mussels |
| Author(s): | Odeyemi OA; Burke CM; Bolch CJS; Stanley R; |
| Address: | "Ecology and Biodiversity Centre, Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Launceston, Australia. Electronic address: olumide.odeyemi@utas.edu.au. Ecology and Biodiversity Centre, Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Launceston, Australia. Centre for Food Innovation, Tasmania Institute of Agriculture (TIA), University of Tasmania, Launceston, Australia" |
| DOI: | 10.1016/j.foodres.2017.10.068 |
| ISSN/ISBN: | 1873-7145 (Electronic) 0963-9969 (Linking) |
| Abstract: | "Under the current commercial practice, live mussels only have 10days' shelf-life. Observed spoilage indices reduce consumers' acceptance, palatability and shelf-life of modified atmosphere packaged (MAP) live mussels. The aims of this study are to isolate specific spoilage bacteria from modified atmosphere packaged live mussels, evaluate isolates for microbial spoilage indices using qualitative methods and volatile metabolites production. Forty-six hydrogen sulphide producing bacteria were isolated and evaluated for trimethylamine n-oxide (TMAO) reduction, proteolytic and lipolytic activities and hydrogen sulphide production. Twenty-eight isolates were obtained from pouch water and 18 from mussel meat. All the isolates could produce H(2)S on Iron agar at 25 degrees C while 30/46 produced H(2)S at 4 degrees C and tolerate 0-6% NaCl. Four (4/46) isolates could not hydrolyse mussel protein. Over 80% isolates reduced TMAO to TMA in 3days with the production of H(2)S. Results of this study shows hydrogen sulphide producing bacteria isolated from MAP live mussels produce microbial spoilage indices. Isolate with highest enzymatic activities and hydrogen sulphide production was identified as Shewanella baltica using 16S rRNA gene. Axenic culture of the isolate was inoculated into sterile mussel broth. Inoculated sample was further stored at 4 degrees C for 10days for spoilage study. Volatile metabolites produced during storage were evaluated using headspace solid phase micro-extraction gas chromatography mass spectrometry (HS-SPME GC/MS). A total of 44 compounds were identified in the sample after 10days while 27 compounds were identified in inoculated mussel broth. Group of compounds identified are alcohols, aldehydes, phenol, furans, ketone, esters, organic acid, aromatic hydrocarbons, alkanes, nitrogen and sulphur containing compounds. Dimethyl trisulphide, methyl-phenol, 3,5-octadiene and thiohexene were unique to inoculated mussel broth. Understanding spoilage mechanism and attendant spoilage indices will help in designing effective mussel quality protocols and shelf-life extension" |
| Keywords: | Animals Bivalvia/*microbiology Food Microbiology/*methods Food Packaging/*methods Gas Chromatography-Mass Spectrometry Seafood/*microbiology Shewanella/isolation & purification/*metabolism Solid Phase Microextraction Time Factors Volatile Organic Compound; |
| Notes: | "MedlineOdeyemi, Olumide A Burke, Christopher M Bolch, Christopher J S Stanley, Roger eng Research Support, Non-U.S. Gov't Canada 2018/02/02 Food Res Int. 2018 Jan; 103:415-425. doi: 10.1016/j.foodres.2017.10.068. Epub 2017 Oct 31" |
