The dynamics of Pseudomonas and volatilome during the spoilage of gutted sea bream stored at 2 °C

• Pseudomonas species succession was determined during gutted sea bream spoilage.
• Pseudomonas fluorescens dominated during spoilage of gutted sea bream.
• Volatile compounds profile was determined during gutted sea bream spoilage.
• Various microbial volatiles suggested as potential chemical spoilage indices.

The microbial diversity of the population grown on a selective medium for pseudomonads (cetrimide-fucidin-cephaloridine agar – CFC) and volatile organic compound (VOC) profile were determined during storage of gutted sea bream (Sparus aurata) at 2 °C. Microbiological and sensory changes were also monitored. Pseudomonas spp. were determined as the predominant spoilage microorganisms of gutted sea bream. A total of 104 colonies were collected from CFC plates and identified by 16S rRNA gene sequence analysis at the following three time intervals: day 1, after four days of storage (day 5) and at the sensory rejection point (day 9). Pseudomonas fluorescens was found as more abundant than the rest Pseudomonas species (Pseudomonas putida, Pseudomonas vranovensis), being the only bacterial species detected on CFC at the end of shelf life. VOCs such as 2-ethyl-1-hexanol, 2-methyl-1-butanol, 3-methylbutanal, isoamyl butyrate, ethyl acetate and ethyl esters of propionate, butyrate and isobutyrate increased during storage and constitute potential chemical spoilage indices (CSIs) candidates for freshness/spoilage monitoring throughout storage.