Evaluation of spoilage potential and volatile metabolites production by Shewanella baltica isolated from modified atmosphere packaged live mussels. (January 2018)

• Record Type: Journal Article
• Authors: Odeyemi, Olumide A.; Burke, Christopher M.; Bolch, Christopher J.S.; Stanley, Roger
• Is Part Of: Food research international. Volume 103(2018)
• Page Start: 415
• Page End: 425
• Publication Date: 2018-01
• Subjects: Seafood spoilage -- Microbial shelf-life -- Volatile metabolites; Food -- Analysis -- Periodicals; Food industry and trade -- Periodicals; Food industry and trade -- Canada -- Periodicals; Food Technology -- Periodicals; Food -- Periodicals; Food-Processing Industry -- Periodicals; Aliments -- Industrie et commerce -- Périodiques; Aliments -- Industrie et commerce -- Canada -- Périodiques; Aliments -- Recherche -- Périodiques; Food industry and trade; Canada; Periodicals; Electronic journals; 664.005
• DOI: 10.1016/j.foodres.2017.10.068
• Languages: English
• ISSNs: 0963-9969

Abstract

Abstract: Under the current commercial practice, live mussels only have 10 days' 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 H2 S on Iron agar at 25 °C while 30/46 produced H2 S at 4 °C and tolerate 0–6% NaCl. Four (4/46) isolates could not hydrolyse mussel protein. Over 80% isolates reduced TMAO to TMA in 3 days with the production of H2 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 °C for 10 days 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 10 days 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. Graphical abstract: Fig. 1. Summary of studies on isolation of S. baltica, spoilage potential and volatile metabolites analysis. Highlights: Isolation of spoilage bacteria from modified atmosphere packaged live mussels Biochemical and molecular characterization of spoilage bacteria Evaluation of spoilage potential of isolated bacteria Identification of spoilage volatile metabolites produced by Shewanella baltica