Combined Effect of Nisin and Commercial Pectin-hydrolysate Treatment on Survival and growth of Listeria monocytogenes in Soy-seasoned Salmon Roe Products

Abstract

Soy-seasoned salmon roe products are commonly eaten in Japan; long-term preservation of these items requires refrigeration. However, salmon roe products are often contaminated with Listeria monocytogenes, which can potentially cause outbreaks of listeriosis. This study focused on developing a method to inhibit the growth of L. monocytogenes in salmon roe products by treating these foodstuffs with a combination of nisin and commercial pectin-hydrolysate, Neupectin L. We determined that treatment with 0.5 mg g⁻¹ nisin completely inhibited the growth of L. monocytogenes in raw salmon roe. However, treatment with nisin alone did not inhibit L. monocytogenes in soy-seasoned salmon roes. Further work showed that combined treatment with 0.5 mg g⁻¹ nisin and 0.5% Neupectin L completely inhibited the growth of L. monocytogenes during incubation at 12°C. Therefore, this combination is an alternative way to control L. monocytogenes growth in salmon roe products.