Plant pomaces in suitable forms (powders, extracts) can be used in foods of animal origin to increase the nutritional value and safety of these foods. In the present study, water extracts of apple, black currant, rhubarb and tomato pomaces were used in fish marinade solutions to evaluate their effect on the growth dynamics of microorganisms and the growth potential of Listeria monocytogenes by challenge testing. The results showed that mesophilic aerobic microorganisms, Pseudomonas spp., yeasts and moulds remained at acceptable levels throughout the predetermined storage period. The challenge test results showed that the overall growth potential of L. monocytogenes in all marinated rainbow trout samples remained at ≤0.5 log10 cfu/g during the study period, and none of the marinated fish samples supported the growth of L. monocytogenes. In addition, the effect of fruit and berry pomaces on the sensory properties of marinated rainbow trout samples was evaluated. The results revealed that it is possible to effectively use fruit and berry pomaces in marinated fish products, ensuring food safety, high microbiological quality, acceptable sensory characteristics and a sufficiently long shelf life of the products.
Keywords: Listeria monocytogenes; challenge test; fruit and berry pomaces; marinades; microbial counts; rainbow trout; sensory evaluation.