Evaluation of compounds for antibacterial activity against spoilage bacteria inoculated on rainbow trout tissue
A screening procedure using sterile chunks of rainbow trout (' Oncorhynchus mykiss') as the growth medium was used to evaluate compounds for their efficacy in controlling the growth of two fish spoilage bacteria, ' Pseudomonas putida' and 'Shewanella putrifaciens'. The fish chunks (4 cm2) were inoculated with spoilage bacteria and then dipped into various treatment solutions for 30 seconds. After incubating at room temperature for 24 hours, bacterial counts were taken and log reduction ratio values (LR) calculated. In this study, all test compounds were considered effective inhibitors if their log reduction values minus one standard deviation (LR-1SD) was equal to or greater than 3.0. Acetic acid, propionic acid, formic acid, valeric acid, allyl isothiocyanate (AIT), hexadecytrimethylammonium bromide (HTAB), ethanol, clove oil, lemongrass oil, peppermint oil, cinnamon oil and 24 hours of exposure to acid water all produced LRs of 3 logs or greater against 'P. putida'. 'S. putrifaciens' was found to be more sensitive to treatments than 'P. putida'. All substances that were classified as inhibitors caused potentially detrimental sensory changes to the trout meat.