Changes in Bacterial Flora and Predominant Spoilage Bacteria in Squid during Low Temperature Storage

Bacterial flora in squid stored at 0, 5, 10, and 15 ℃ were analyzed qualitatively and quantitatively. The results showed that the bacterial flora of squid was complex on initial storage, with 91.48% gram-negative bacteria and 4.26% gram-positive bacteria. The predominant bacterial flora was composed of Aeromonas spp.(27.66%), Chryseomonas luteola(23.40%), and Pseudomonas spp.(17.02%). In addition, a certain proportion of Acinetobacter lwoffii and Pantoea agglomerans was also detected. During aerobic storage at 0, 5, 10, and 15 ℃, the bacterial flora gradually became more uniform and a trend of increasing Pseudomonas spp. was apparent. The high quality lives(HQL) of the squid samples were 360, 239, 96, and 47 h, respectively, while the shelf lives(SL) were 525, 286, 147, and 86 h, respectively. In addition, at the end of HQL at 0, 5, 10, and 15 ℃, total volatile base nitrogen(TVBN) was 17.15 ± 0.29 mg/100 g, and total viable count(TVC) was 5.89 ± 0.40 Lg CFU/g. The percentages of Pseudomonas spp. were 84.09%, 72.09%, 65.52%, and 76.36%, respectively, with an average percentage of 75.92%. At the end of SL at 0, 5, 10, and 15 ℃, TVBN was 30.05 ± 0.92 mg/100 g and TVC was 8.33 ± 0.30 Lg CFU/g. The percentages of Pseudomonas spp. were 93.24%, 90.53%, 88.57%, and 81.95%, respectively, and the average percentage was 87.63%. Therefore, Pseudomonas spp. was the predominant spoilage bacteria of squid stored between 0 and 15 ℃.