Assessing and enhancing the antimicrobial effect of nisin in soy-seasoned salmon Oncorynchus keta roe using a Pediococcus pentosaceus fermentate and pectin
2010
Bagenda, D.K., Future Univ.-Hakodate, Hokkaido (Japan) | Yamazaki, K. | Kobayashi, T. | Kawai, Y.
The compatibility and potential of nisin, a Pediococcus pentosaceus fermentate, and pectin to inhibit Listeria monocytogenes in soy-seasoned salmon roe at 5 and 12degC was studied. The compatibility of nisin and soy-seasoning was assessed by adding 6.3 micro g/g of nisin to freshly washed or soy-seasoned (60% soy, 15% sweetsake, 5% sugar and 15% water) roe and monitoring the growth of an inoculum of L. monocytogenes (5.6 Log CFU/g; strains IID 578, IID 581 and ATCC 7644) as well as residual nisin concentrations at l2degC. The combined antimicrobial potential was determined by monitoring growth of the inoculum (5.2 Log CFU/g) in roe when the soy-seasoning contained nisin (0.05 g/ml), fermentate powder made by freeze-drying a broth culture of P. pentosaceus (0.1 g/ml), and 2% pectin at 5 or l2degC. Chloride content, total acid content and the effect of pectin on acceptability of roe were also determined. Nisin was more effective in soy-seasoned roe than in freshly washed roe. Microbial growth was completely inhibited by a combination of soy-seasoning, nisin, the fermentate and pectin. Despite its viscosity, pectin did not significantly affect the chemical properties or acceptability of roe relative to pectin-free roe samples (P 0.05). Based on these results, we conclude that nisin's potential as an antimicrobial agent in soy-seasoned roe can be enhanced using fermentates and pectin.
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