The spoilage flora of vacuum-packaged, sodium nitrite or potassium nitrate treated, cold-smoked rainbow trout stored at 4°C or 8°C

Ulrike Lyhs, Johanna Björkroth, Eija Hyytiä, Hannu Korkeala

Research output: Contribution to journalJournal articleResearchpeer-review

135 Downloads (Pure)

Abstract

The spoilage flora of vacuum-packaged, salted, cold-smoked rainbow trout fillets, with or without the addition of nitrate or nitrite, stored at 4°C and 8°C, was studied. Of 620 isolates, lactic acid bacteria were the major fraction (76%), predominating in all samples of spoiled product. However, the phenotypical tests used were insufficient to identify the lactic acid bacteria to the species level. Gram-positive, catalase-positive cocci, Gram- negative, oxidase-negative rods and Gram-negative, oxidase-positive rods were found in 6%, 16% and 2% of the samples, respectively. Of 39 Gram-positive, catalase-positive cocci, 29 were identified as staphylococci and 10 as micrococci. Eighty-five isolates were found to belong to the family Enterobacteriaceae, with 45 of those being Serratia plymuthica. Eleven isolates from the nitrate treated samples stored at 8°C were identified as Pseudomonas aeruginosa. The occurrence of P. aeruginosa and staphylococci in the nitrate-containing samples, stored at 8°C, may cause problems with respect to the safety of the product. The types of lactic acid and other bacteria in the spoilage flora were generally reduced by the addition of nitrate or nitrite to fillets.
Original languageEnglish
JournalInternational Journal of Food Microbiology
Volume45
Issue number2
Pages (from-to)135-142
ISSN0168-1605
DOIs
Publication statusPublished - 1998
Externally publishedYes

Keywords

  • Food Science
  • Microbiology
  • Cold-smoking
  • Fish
  • NaCl
  • Nitrate
  • Nitrite
  • Spoilage
  • Vacuum-packaging
  • potassium nitrate
  • sodium nitrate
  • article
  • bacterium identification
  • enterobacteriaceae
  • food contamination
  • food freezing
  • food quality
  • food storage
  • pseudomonas aeruginosa
  • rainbow trout
  • serratia
  • Animals
  • Bacteria
  • Colony Count, Microbial
  • Fish Products
  • Food Microbiology
  • Food Packaging
  • Food Preservation
  • Humans
  • Nitrates
  • Oncorhynchus mykiss
  • Potassium Compounds
  • Refrigeration
  • Smell
  • Sodium Chloride
  • Sodium Nitrite
  • Taste
  • cold-smoked rainbow trout fish
  • storage temperature
  • Facultatively Anaerobic Gram-Negative Rods Eubacteria Bacteria Microorganisms (Bacteria, Eubacteria, Microorganisms) - Enterobacteriaceae [06702] Enterobacteriaceae spoilage organism Serratia plymuthica spoilage organism
  • Gram-Negative Aerobic Rods and Cocci Eubacteria Bacteria Microorganisms (Bacteria, Eubacteria, Microorganisms) - Pseudomonadaceae [06508] Pseudomonas aeruginosa spoilage organism
  • Gram-Positive Cocci Eubacteria Bacteria Microorganisms (Bacteria, Eubacteria, Microorganisms) - Micrococcaceae [07702] micrococci spoilage organism staphylococci spoilage organism
  • Microorganisms (Bacteria, Eubacteria, Microorganisms) - Bacteria [05000] lactic acid bacteria spoilage organism
  • potassium nitrate 7757-79-1 food preservative
  • sodium nitrite 7632-00-0 food preservative
  • 10060, Biochemistry studies - General
  • 13502, Food technology - General and methods
  • 23001, Temperature - General measurement and methods
  • 39008, Food microbiology - General and miscellaneous
  • vacuum-packaging food preservation method
  • Foods
  • BACTERIA
  • FOOD SAFETY ANIMAL FOODS
  • NITRATES
  • NITRITES
  • RAINBOW TROUT
  • SMOKED FOODS
  • STORAGE
  • TROUT
  • Fish and fish products
  • Fish and marine products

Fingerprint Dive into the research topics of 'The spoilage flora of vacuum-packaged, sodium nitrite or potassium nitrate treated, cold-smoked rainbow trout stored at 4°C or 8°C'. Together they form a unique fingerprint.

Cite this