Effect of Listeria monocytogenes inoculation, sodium acetate and nisin on microbiological and chemical quality of grass carp Ctenopharyngodon idella during refrigeration storage
In this study, the microbiological quality and lipid oxidation of the grass carp (Ctenopharyngodon idella) fillets treated by dipping in sodium acetate (0, 1 and 3%), nisin (0, 0.1 and 0.2%) or their combination were evaluated during 16 days of refrigeration storage. Antilisterial effect of nisin was enhanced with the increased concentration of sodium acetate. With increasing the concentrations of sodium acetate, mesophilic counts were lower but regarding nisin, better results were obtained by applying 0.1% nisin. Greater inhibition of mesophile bacteria was observed when combination treatment was used. The number of lactobacillus was lower when higher concentrations of sodium acetate and nisin were used. Peroxide, TBA and total viable base nitrogen (TVB-N) values were lower in the samples treated with both nisin and sodium acetate and higher results were obtained in the combination treatments.
Key words: Listeria monocytogenes, nisin, sodium acetate, microbial quality, chemical quality, grass carp.