Effect of Sargassum tenerrimum extract, nisin z and aureomycin antibiotic on bacterial growth of Litopenaeus vannamei during ice storage

Seafood due to high water activity, neutral pH, high ratio of free amino acids are involved in microbial spoilage and consequently their quality and shelf life are reduced. In this study, the preservative effect of powdered ice in four forms of pure and combined with Sargassum tenerrimmum algae extract, aeromycin antibiotic and nisin-z on increasing the shelf life of Vanami shrimp during 12 days of storage in refrigeration was evaluated. Shrimps were prepared from Gomishan Breeding Center and all experiments were performed in the Faculty of Fisheries, Gorgan University of Agricultural Sciences and Natural Resources. Shrimp covered with ice were evaluated every 3 days by measuring the microbiological characteristics of Common spoilage bacteria (CSB), Psychrophilic bacteria (PSB), Lactic acid bacteria (LAB) and Enterobacteriaceae (EB). The fastest deterioration trend of all bacterial analyzes was observed in the control and algae extract samples and these two treatments showed the highest increase at the end of storage time (p <0.05). Ice containing nisin z had a relatively good preservative effect on CSB, LAB, and PSB, but was ineffective against EB. The antibiotic aeromycin showed a significant inhibitory effect, so that the growth of EB and LAB during the storage time was close to zero. CSB and PSB had also similar conditions in this treatment and even decreased during storage.