Microbial Safety and Sensory Analyses of Cold-Smoked Salmon Produced with Sodium-Reduced Mineral Salts and Organic Acid Salts

Even Heir; Maria Jacobsen; Mari Øvrum Gaarder; Ingunn Berget; Paw Dalgaard; Merete Rusås Jensen; Askild L Holck

doi:10.3390/foods11101483

Microbial Safety and Sensory Analyses of Cold-Smoked Salmon Produced with Sodium-Reduced Mineral Salts and Organic Acid Salts

Foods. 2022 May 19;11(10):1483. doi: 10.3390/foods11101483.

Authors

Even Heir¹, Maria Jacobsen^{1

2}, Mari Øvrum Gaarder¹, Ingunn Berget¹, Paw Dalgaard², Merete Rusås Jensen¹, Askild L Holck¹

Affiliations

¹ Nofima AS-Norwegian Institute of Food, Fisheries and Aquaculture Research, P.O. Box 210, N-1431 Ås, Norway.
² National Food Institute (DTU Food), Technical University of Denmark, Kemitorvet, Bldg 202, DK-2800 Kongens Lyngby, Denmark.

Abstract

Cold-smoked (CS) salmon contains high levels of sodium salts, and excess dietary sodium intake is associated with an array of health complications. CS salmon may also represent a food safety risk due to possible presence and growth of the foodborne pathogen Listeria monocytogenes which may cause fatal human infections. Here we determine how reformulated CS salmon using commercial sodium-reduced salt replacers containing KCl (e.g., Nutek, Smart Salt, SOLO-LITE) and acetate-based preservative salts (Provian K, proviant NDV) affect sensory properties, quality, and microbial safety. Initial sensory screening of sodium-reduced CS salmon was followed by L. monocytogenes growth analyses in selected variants of reformulated CS salmon, and finally by analyses of CS salmon variants produced in an industrial smokehouse. Projective mapping indicated overall minor sensory changes in sodium-replaced samples compared with a conventional product with NaCl. Growth of L. monocytogenes was temperature-dependent (4 °C vs. 8 °C storage) with similar growth in sodium-reduced and conventional CS salmon. The addition of 0.9% of the preservative salts Provian K or Provian NDV gave up to 4 log lower L. monocytogenes counts in both sodium-reduced and conventional cold-smoked salmon after 29 days of chilled storage. No changes in pH (range 6.20−6.33), aw levels (range 0.960−0.973), or weight yield (96.8 ± 0.2%) were evident in CS salmon with salt replacers or Provian preservative salts. Analyses of CS salmon produced with selected mineral salt and preservative salt combinations in an industrial salmon smokery indicated marginal differences in sensory properties. Samples with the preservative salt Provian NDV provided L. monocytogenes growth inhibition and low-level total viable counts (<2.8 log/g) dominated by Photobacterium and Carnobacterium during storage. Production of sodium-reduced CS salmon with inhibiting salts provides a simple method to achieve a healthier food product with increased food safety.

Keywords: Listeria monocytogenes; cold-smoked salmon; food safety; organic acid salts; potassium chloride; sensory profile; sodium reduction.

Grants and funding

This research was funded by a research grant from the Fisheries and Aquaculture Industry Research Fund (FHF grant no. 901583). The work was also partially financed by The Research Council of Norway by grants on research infrastructure (grant no. 296083).