Smoked sprats (Sprattus sprattus balticus) from the Baltic Sea are one of the most popular processed fish products in Latvia. The amount of catching and demand is annually increasing. For producers, it is important to provide stable quality throughout the year, which sometimes is challenging due to many factors. Smoked fish quality depends not only on the seasonality, but also on the applied technologies. The aim of the current study was to review research findings about factors affecting the smoked fish quality. The databases of Science Direct, Web of Science, Wiley Online Journals and Google Scholar were searched. The first parameter that affects quality of fish till processing is raw material, its catching place and season, as well as whether it is fresh or frozen fish, that includes not only microbiological parameters, but also physical and chemical changes in fish depending on the storage conditions. The second parameter is the applied pre-treatment methods (using salt, acids) before processing, which can improve fish texture and make better result for smoked fish. The third parameter is the used technology for the fish processing, heat treatment methods use of wood chips or liquid smoke, or adjustment of smoking conditions. These all together make a lot of sensorial and textural changes in the final product. If any of these parameters is changed during processing, they can affect the smoked fish quality. Therefore, to ensure constant quality of smoked fish, in-depth knowledge of parameters is extremely important.

In the fish processing sector, the further exploitation of by-products and wastes left after industrial production promotes sustainability of raw materials, access to added value and increased profitability, as well as contributes to environmental protection by reducing the volume of dumped products. Besides obvious value-added features, it also addresses the clear market demand dictated by prospects of the population growth. Given the limitations for further expansion of the husbandry sector, fish-based items available for human consumption represent a major avenue for coping with the pressing demands of increased population and enable the development of innovative food items of high nutritional importance. Current research is focused on the analysis of fish processing by-product utilization possibilities available up to date and introduces empirical findings of innovative food product development made on the basis of by-products left after traditional canned “Sprats in oil” production. In Latvia, “Sprats in oil” production is an integral part of fish processing sector and the rural economy overall. The production accounts for at least 30% of raw material left as by-products (smoked heads and, in some cases, tails) after such technological stage as smoked sprats processing into cans. Efforts were made to prepare value-added and attractive to customer food product made out of this fish-processing by-products, which are typically processed to a fishmeal or just dumped as waste. The study demonstrates a strong potential for its utilization to a range of fish pâté with various flavours and of high nutritious value.

In presented study we have investigated an occurrence of 15 polycyclic aromatic hydrocarbons (PAH) in different smoked meat and fish samples. After clean up and extraction procedures, the samples were analyzed by gas chromatography-mass spectrometry (GC-MS). Large variability in PAH levels for samples of the same type was found, thus the contamination level is not strongly correlated with the type of product. In the smoked fish samples concentrations of total PAHs ranged from 0.26 to 104 mu g kgE1, and in smoked meat samples - from 1.7 to 197 mu g kgE-1. In general, the predominating PAHs in all samples were benz(a)anthracene, crysene, and cyclopenta(c,d)pyrene. Also the elimination of PAHs in smoked fish by UV irradiation was investigated. Significant decrease in carcinogenic PAH content in smoked fish was found after a 15 min exposure.