Spoilage potential of three different bacteria isolated from spoiled grass carp (Ctenopharyngodon idellus) fillets during storage at 4 °C

Abstract

In this study, the growth of Aeromonas hydrophila, Pseudomonas jessenii and Shewanella putrefaciens in sterile grass carp fillets stored at 4 °C was evaluated, as well as their effect on physicochemical and sensory spoilage. A. hydrophila and P. jessenii strains increased rapidly during the first 10 days, but S. putrefaciens showed a lag phase. The highest producers of total volatile basic nitrogen were A. hydrophila and P. jessenii, which reached a maximum level around 30 mg/100 g after 16 days. P. jessenii was an active producer of biogenic amines in grass carp fillets and was the only bacterium that produced histamine among the three bacteria. All the inoculated samples produced abundant cadaverine, which reached 51.5, 54.8 and 37.8 mg/mL for A. hydrophila, P. jessenii, and S. putrefaciens, respectively. The influence of bacteria on the thiobarbituric acid reactive substances (TBARS) value of grass carp fillets was slight. Volatile compounds, such as tetradecanal and 1-hexadecanol, were detectable only for S. putrefaciens, which also produced the highest amount of 1-octen-3-ol, nonanal and 2-ethylcyclohexanol. P. jessenii produced high levels of ketones such as 2-nonanone and 2-undecanone.