Development and evaluation of salt-reduced seafood products containing alternative types of preservation

Abstract

Different products of cold smoked salmon (CSS) were developed with reduced salt content, herbs and Nordic vinegar as additives. The CCS was produced with a dry-salting method and the salt levels in the products were reduced from 10% to 4% added on top during production. The herbs and Nordic vinegar was used in CSS with the aim to inhibit growth of the pathogen bacteria Listeria monocytogenes. The products were tested for sensory quality in a sensory evaluation. The top ranked products were CSS with chili and ginger, Angelica and angelica seeds, and juniper berries, respectively. The vinegar did not provide any undesirable changes to the sensory properties of the CSS products. The products with best sensory quality were used in a challenge test with inoculum of L. monocytogenes. In the challenge test, a sample only added vinegar and a sample from Meyers normal production without any specific preservation was also included. In the challenge test it was observed that growth of L. monocytogenes was inhibited or prevented in samples with added vinegar. Due to the product characteristics it could be seen that acetic acid from the vinegar had diffused into the fish and the pH was lowered in the samples where vinegar was added. The salt levels were variable in the different products, and by reducing the salt from 10% down to 4% added on top, there were just small differences in uptake. A high variation in uptake of salt and acetic acid for the different regions of the fish (head, mid and tale parts) was also observed. Consequently, it was a challenge to reduce the salt content in CSS using a dry-salting method. However, this study showed that addition of Nordic vinegars to CSS could be used to stabilize growth of L. monocytogenes so it fulfills the EU-regulation on ready-to-eat foods.