Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Jun 11;14(6):580.
doi: 10.3390/pathogens14060580.

Characterization of Microbial Growth, Pathogen Presence, and Histamine Accumulation in Chilled Rainbow Trout and Mackerel Samples Collected from Romanian Markets

Vida Silviu  1 , Alexandra Tabaran  1 , Oana Lucia Crişan Reget  1 , Mihaela Niculina Duma  2 , Luciana Cătălina Panait  1 , Sorin Daniel Dan  1
Affiliations

Characterization of Microbial Growth, Pathogen Presence, and Histamine Accumulation in Chilled Rainbow Trout and Mackerel Samples Collected from Romanian Markets

Vida Silviu et al. Pathogens. .

Abstract

This study aimed to evaluate microbial growth, pathogen presence, and histamine production in rainbow trout and mackerel stored on flaked ice over their shelf life. A total of 72 fish samples (rainbow trout and mackerel) were analyzed across four storage intervals (day 1, 3, 9, 12/11) on flaked ice. TVC increased from 2.59 to 5.04 log cfu/g in rainbow trout and from 3.18 to 4.88 log cfu/g in mackerel over the storage period. Significant increases were observed in Pseudomonas, Aeromonas, and Enterobacteriaceae populations, especially after the ninth day. Microbial identification revealed spoilage-associated bacteria, such as Pseudomonas fluorescens and Aeromonas salmonicida, as well as opportunistic pathogens, including Francisella tularensis, Yersinia spp., and Chromobacterium violaceum. Histamine levels rose with storage time but remained below toxic thresholds (<200 mg/kg), peaking at 1.56 mg/kg in trout and 1.87 mg/kg in mackerel. A strong positive correlation was found between TVC and histamine levels (Pearson's r = 0.85 for trout, 0.82 for mackerel). Proper hygiene and storage are crucial, and consumption is recommended before day 9 of storage on flaked ice. Hygiene measures remain essential to minimize contamination risks and preserve product safety.

Keywords: chilling storage; histamine; mackerel; microbial characterization; microbial spoilage; rainbow trout; safety.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
Total viable count, Enterobacteriaceae, Pseudomonas, and Aeromonas count in the case of rainbow trout on flaked ice (Oncorhynchus mykiss) during the shelf life (n = 36, 12 samples/replicate). a Significant differences (p < 0.05) when 1st day compared with the 3rd, 9th, and 12th day.
Figure 2
Figure 2
Total viable count, Enterobacteriaceae, Pseudomonas, and Aeromonas count in the case of mackerel on flaked ice (Scomber scombrus) during the shelf life (n = 36, 12 samples/replicate). a Significant differences (p < 0.05) when 1st day compared with the 3rd, 9th, and 11th day.
Figure 3
Figure 3
Microbial population in the case of frozen rainbow trout (Oncorhynchus mykiss) during the shelf life (n = 12).
Figure 4
Figure 4
Microbial population in the case of rainbow trout (a) (Oncorhynchus mykiss) and mackerel (b) (Scomber scombrus) on flaked ice in the last day of the shelf life (n = 18).
Figure 5
Figure 5
Mean histamine level in the case of rainbow trout (a) (Oncorhynchus mykiss) and mackerel (b) (Scomber scombrus) on flaked ice during the shelf life (n = 36, 12 samples/replicate). a Significant differences (p < 0.05) when compared with the 9th and 11/12th day.
Figure 6
Figure 6
Positive correlation between total viable count and histamine values in the case of rainbow trout (a) (Oncorhynchus mykiss) and mackerel (b) (Scomber scombrus) on flaked ice during the shelf life.
See this image and copyright information in PMC

References

    1. Abisha R., Krishnani K.K., Sukhdhane K., Verma A.K., Brahmane M., Chadha N.K. Sustainable Development of Climate-Resilient Aquaculture and Culture-Based Fisheries Through Adaptation of Abiotic Stresses: A Review. J. Water Clim. Change. 2022;13:2671–2689. doi: 10.2166/wcc.2022.045. - DOI
    1. Khalili Tilami S., Sampels S. Nutritional Value of Fish: Lipids, Proteins, Vitamins, and Minerals. Rev. Fish. Sci. Aquacult. 2017;26:243–253. doi: 10.1080/23308249.2017.1399104. - DOI
    1. Pila M., Stanciuc N., Stanciu S. Fisheries and Aquaculture in Romania: A Global Outlook on Sustainable Development. Sci. Pap. Ser. Manag. Econ. Eng. Agric. Rural Dev. 2023;23:517–522.
    1. Tahiluddin A., Maribao I., Amlani M., Sarri J. A Review on Spoilage Microorganisms in Fresh and Processed Aquatic Food Products. Food Bull. 2022;1:21–36. doi: 10.29329/foodb.2022.495.05. - DOI
    1. Egerton S., Culloty S., Whooley J., Stanton C., Ross R.P. The Gut Microbiota of Marine Fish. Front. Microbiol. 2018;9:873. doi: 10.3389/fmicb.2018.00873. - DOI - PMC - PubMed

LinkOut - more resources