Microbiological quality and shelf-life of vacuum-packaged 'gravad' rainbow trout stored at 3 and 8 °C

Ulrike Lyhs, J. Lahtinen, M. Fredriksson-Ahomaa, E. Hyytia-Trees, K. Elfing, H. Korkeala

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Microbiological and sensory changes of vacuum-packaged 'gravad' rainbow trout slices were studied during storage at 3 and 8 degreesC. At the time of spoilage, after 27 and 20 days of storage at 3 and 8 degreesC, respectively, both mesophilic viable counts (MVC) and psychrotrophic viable counts (PVC) reached 10(6)-10(7)cfu/g at 3 degreesC and 10(7)-10(8) cfu/g at 8 degreesC. H2S-producing bacteria constituted a high proportion of the PVCs and lactic acid bacteria (LAB) counts were lower than the other determined bacterial counts. Sensory scores decreased with increasing MVC and PVC. The judges considered samples unfit for human consumption at MVC and PVC levels exceeding 10(6) and 10(7) cfu/g for samples stored at 3 and 8 degreesC, respectively. At respective levels of 10(7) and 10(8) cfu/g, most of the samples were deemed unfit. The main reasons for sensory rejection at both storage temperatures were the lack of the typical product odour or an ammonia off-odour and colour change to dark violet. The shelf-lives of the rainbow trout slices based on microbiological and sensory analyses were 20 days and 18 days at 3 and 8 degreesC, respectively. (C) 2001 Elsevier Science B.V. All rights reserved.
Original languageEnglish
JournalInternational Journal of Food Microbiology
Issue number3
Pages (from-to)221-230
Publication statusPublished - 2001
Externally publishedYes


  • Food Science
  • Microbiology
  • 'Gravad'
  • Fish
  • Growth curve
  • Sensory property
  • Temperature
  • Vacuum-packaging
  • ammonia
  • analytic method
  • article
  • bacterial count
  • controlled study
  • food spoilage
  • lactic acid bacterium
  • nonhuman
  • rainbow trout
  • shelf life
  • storage
  • temperature sensitivity
  • vacuum
  • Animals
  • Colony Count, Microbial
  • Color
  • Food Handling
  • Food Microbiology
  • Food Packaging
  • Food Preservation
  • Odors
  • Oncorhynchus mykiss
  • Taste
  • Time Factors
  • Vacuum
  • ‘Gravad’
  • FOOD
  • fish
  • vacuum-packaging
  • 'gravad'
  • sensory property
  • growth curve
  • temperature
  • food microbiology
  • food quality
  • food storage conditions
  • gravad rainbow trout chemical analysis, color, fish, microbial analysis, odor, quality, sensory changes, shelf-life, spoilage, storage temperatures
  • Microorganisms (Bacteria, Eubacteria, Microorganisms) - Bacteria [05000] bacteria lactic acid bacteria
  • Microorganisms (Microorganisms) - Microorganisms [01000] microorganism
  • Pisces Vertebrata Chordata Animalia (Animals, Chordates, Fish, Nonhuman Vertebrates, Vertebrates) - Osteichthyes [85206] rainbow trout
  • Primates Mammalia Vertebrata Chordata Animalia (Animals, Chordates, Humans, Mammals, Primates, Vertebrates) - Hominidae [86215] human
  • 13502, Food technology - General and methods
  • 31000, Physiology and biochemistry of bacteria
  • vacuum packaging packing method
  • Foods


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