The commercialization of processed fish products is rising in restaurants and small to medium enterprises. However, there is a lack of data related to the microbiological safety of such products. In this study total aerobic colony count and Enterobacteriaceae, as proxy of process hygiene criteria, and detection of Listeria monocytogenes and concentration of histamine, as food safety criteria, were investigated in Salmo salar (salmon), Xiphias gladius (swordfish) and Thunnus albacares (yellowfin tuna), before, during, and at the end of a dry-curing process, performed in a dedicated cabinet, at controlled temperature, relative humidity and ventilation, up to 240 h. The microbiological parameters were investigated in the tested fish products by culture methods and shotgun metagenomic, while the presence of histamine, and other biogenic amines, was quantified by High Performance Liquid Chromatography. In the raw material, and up to the end of the dry curing process, the concentration of Enterobacteriaceae was always lower than 10 CFU/g, while total aerobic colony counts ranged between 3.9 and 5.4 Log CFU/g in salmon; 5.5 and 5.9 Log CFU/g in swordfish; 4.4 and 4.8 Log CFU/g in tuna. The pH values were significantly different between fish species, in the raw materials and during processing except for T4, occurring 70 h after the start of the process for salmon and after 114 h for swordfish and tuna. Water activity was different at specific sampling points and at the end of processing. Overall, 79 % of the sequences identified in the tested fish samples were assigned to y bacteria. The most abundant phyla were Pseudomonadota, Bacillota and Mycoplasmatota. The microbial populations identified by shotgun metagenomic in the tested fish species clustered well separated one from the other. Moreover, the microbial richness was significantly higher in salmon and tuna in comparison to swordfish. Listeria monocytogenes was not detected in the raw material by using the reference cultural method and very few reads (relative abundance <0.007) were detected in swordfish and tuna by shotgun metagenomic. Histamine producing bacteria, belonging to the genera Vibrio, Morganella, Photobacterium and Klebsiella, were identified primarily in swordfish. However, histamine and other biogenic amines were not detected in any sample. To the best of our knowledge this is the first paper reporting time point determinations of microbiological quality and safety parameters in salmon, swordfish and tuna, before, during and at the end of a dry-curing process. The data collected in this paper can help to predict the risk profile of ready to eat dry-cured fish products during storage before consumption.

Indio, V., Savini, F., Gardini, F., Barbieri, F., Prandini, L., Mekonnen, Y.T., et al. (2024). Microbiological safety of dry-cured fish from the raw material to the end of processing. INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY, 415(16 April 2024), 1-10 [10.1016/j.ijfoodmicro.2024.110641].

Microbiological safety of dry-cured fish from the raw material to the end of processing

Indio, Valentina;Savini, Federica
;
Gardini, Fausto;Barbieri, Federica;Prandini, Laura;Mekonnen, Yitagele Terefe;Tomasello, Federico;Giacometti, Federica;Seguino, Alessandro;Serraino, Andrea;De Cesare, Alessandra
2024

Abstract

The commercialization of processed fish products is rising in restaurants and small to medium enterprises. However, there is a lack of data related to the microbiological safety of such products. In this study total aerobic colony count and Enterobacteriaceae, as proxy of process hygiene criteria, and detection of Listeria monocytogenes and concentration of histamine, as food safety criteria, were investigated in Salmo salar (salmon), Xiphias gladius (swordfish) and Thunnus albacares (yellowfin tuna), before, during, and at the end of a dry-curing process, performed in a dedicated cabinet, at controlled temperature, relative humidity and ventilation, up to 240 h. The microbiological parameters were investigated in the tested fish products by culture methods and shotgun metagenomic, while the presence of histamine, and other biogenic amines, was quantified by High Performance Liquid Chromatography. In the raw material, and up to the end of the dry curing process, the concentration of Enterobacteriaceae was always lower than 10 CFU/g, while total aerobic colony counts ranged between 3.9 and 5.4 Log CFU/g in salmon; 5.5 and 5.9 Log CFU/g in swordfish; 4.4 and 4.8 Log CFU/g in tuna. The pH values were significantly different between fish species, in the raw materials and during processing except for T4, occurring 70 h after the start of the process for salmon and after 114 h for swordfish and tuna. Water activity was different at specific sampling points and at the end of processing. Overall, 79 % of the sequences identified in the tested fish samples were assigned to y bacteria. The most abundant phyla were Pseudomonadota, Bacillota and Mycoplasmatota. The microbial populations identified by shotgun metagenomic in the tested fish species clustered well separated one from the other. Moreover, the microbial richness was significantly higher in salmon and tuna in comparison to swordfish. Listeria monocytogenes was not detected in the raw material by using the reference cultural method and very few reads (relative abundance <0.007) were detected in swordfish and tuna by shotgun metagenomic. Histamine producing bacteria, belonging to the genera Vibrio, Morganella, Photobacterium and Klebsiella, were identified primarily in swordfish. However, histamine and other biogenic amines were not detected in any sample. To the best of our knowledge this is the first paper reporting time point determinations of microbiological quality and safety parameters in salmon, swordfish and tuna, before, during and at the end of a dry-curing process. The data collected in this paper can help to predict the risk profile of ready to eat dry-cured fish products during storage before consumption.
2024
Indio, V., Savini, F., Gardini, F., Barbieri, F., Prandini, L., Mekonnen, Y.T., et al. (2024). Microbiological safety of dry-cured fish from the raw material to the end of processing. INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY, 415(16 April 2024), 1-10 [10.1016/j.ijfoodmicro.2024.110641].
Indio, Valentina; Savini, Federica; Gardini, Fausto; Barbieri, Federica; Prandini, Laura; Mekonnen, Yitagele Terefe; Tomasello, Federico; Giacometti, ...espandi
File in questo prodotto:
File Dimensione Formato  
1-s2.0-S0168160524000850-main (1).pdf

accesso aperto

Tipo: Versione (PDF) editoriale
Licenza: Licenza per Accesso Aperto. Creative Commons Attribuzione - Non commerciale - Non opere derivate (CCBYNCND)
Dimensione 5.37 MB
Formato Adobe PDF
5.37 MB Adobe PDF Visualizza/Apri
1-s2.0-S0168160524000850-mmc1.docx

accesso aperto

Tipo: File Supplementare
Licenza: Licenza per Accesso Aperto. Creative Commons Attribuzione - Non commerciale - Non opere derivate (CCBYNCND)
Dimensione 88.4 kB
Formato Microsoft Word XML
88.4 kB Microsoft Word XML Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/994708
Citazioni
  • ???jsp.display-item.citation.pmc??? 0
  • Scopus 2
  • ???jsp.display-item.citation.isi??? 2
social impact