Abstract:

The aims of this study were to clarify the changes in bacterial phases during low-temperature storage and the
spoilage mechanism of Penaeus vannamei. The sensory evaluation, total volatile base nitrogen (TVB-N) and total bacterial
count of Penaeus vannamei were measured. The dominated strains from Penaeus vannamei at different storage temperatures
were isolated, purified, and then identified by ATB ExpressionTM reader. The results showed that in cold, ice-temperature
and frozen storage, the shelf life of Penaeus vannamei were 3, 8, and 56 days, respectively. At the end of shelf-life, the
total number of bacteria was 6.76, 6.82, and 5.91 (lg(CFU/g)), respectively. The level of TVB-N was 27.06, 29.96, and
27.45 mg/100 g, respectively. In the early storage stage, the dominant strains were Chryseobacterium meningosepticum
(22.0%) and Pseudomona sp. (18.4%), whereas Shewanella putrefaciens (35.1%) and Pseudomonas sp. (24.3%) were
the dominant strains at the end of the shelf life under cold storage conditions. Shewanella putrefaciens (32.0%) and
Chryseobacterium meningosepticum (27.0%) were the dominant strains at the end of the shelf life under ice-temperature
storage conditions, and Aeromonas sobria (30.5%) and Photobacterium damselae (25.0%) were the dominant strains at the
end of the shelf life under frozen storage conditions.

Key words: Penaeus vannamei, storage temperature, bacterial phase, dominant strains