The prevention of fish spoilage by high antioxidant Australian culinary plants: Shewanella putrefaciens growth inhibition
Summary Shewanella putrefaciens is a marine bacterium and a major microbial cause of spoilage in low temperature stored seafood. A survey of fruits and culinary herbs was undertaken on Australian plants with high antioxidant capacities. Twenty eight extracts from thirteen plant species were investigated for the ability to inhibit S. putrefaciens growth. Of these, eight extracts (28.6% substantially inhibited S. putrefaciens growth. The muntries (Kunzea pomifera) lemon aspen (Acronychia acidula) and desert lime (Citrus glauca) extracts were efficient anti S. putrefaciens agents, with MIC values =3000 mg mL 1. Of these, the muntries methanolic extract was the most potent growth inhibitor (MIC 2240 mg mL 1) The aqueous desert lime extract was also an effective growth inhibitor (MIC of 3857 mg mL 1) whilst the methanolic bush tomato (Solanum aviculare) aqueous muntries and Davidson's plum (Davidsonia pruriens) extracts displayed moderate S. putrefaciens growth inhibition. All extracts were nontoxic in the Artemia fransiscana bioassay, with LC50 values >1000 mg mL 1) Nontargeted HPLC QTOF mass spectroscopy (with screening against three compound databases) putatively identified twenty compounds that were present in both inhibitory muntries extracts. The low toxicity of these extracts and their inhibitory bioactivity against S. putrefaciens indicates their potential as natural fish and seafood preservatives.