Quality of ready-to-eat swordfish fillets inoculated with Lactobacillus paracasei IMPC 2.1

The quality of marinated ready-to-eat (RTE) swordfish fillets, with or without inoculation with the probiotic strain Lactobacillus paracasei IMPC 2.1, was assessed over 3 months of refrigerated storage at 4 °C. RTE probiotic and control fish fillets were sampled after 7, 14, 30, 60, and 90 days of storage. Microbiological tests were performed, and fatty acid (FA) profiles and malondialdehyde content were examined. Microbiological counts, including total viable count, lactic acid bacteria (LAB), yeasts, moulds, Enterobacteriaceae, and Pseudomonadaceae were determined.

Inoculation successfully ensured the growth of the probiotic strain and prevented the growth of other LAB. The two RTE products showed significant differences in lipid profile and lipid oxidation during storage. In particular, inoculation with L. paracasei IMPC 2.1 increased the amount of polyunsaturated FAs and limited the amount of monounsaturated FAs and oleic acid, as well as lipid oxidation. It thus represents an interesting strategy for preserving the chemical quality of fish fillets and an alternative means of delivering probiotics.

Probiotic inoculation with Lactobacillus paracasei seemed to delay lipid oxidation of the fish flesh and increase the retention of polyunsaturated FAs, suggesting a potential application for this strain in the seafood industry. © 2018 Society of Chemical Industry.