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Inhibitory effect of Lactobacillus plantarum Tennozu-SU2 and Lactococcus lactis subsp. lactis BF1 on Salmonella Typhimurium and Listeria monocytogenes during and post fermentation of soymilk

Haraguchi, Yutaka, Goto, Minori, Kuda, Takashi, Fukunaga, Mayu, Shikano, Ayane, Takahashi, Hajime, Kimura, Bon
Lebensmittel-Wissenschaft + [i.e. und] Technologie 2019 v.102 pp. 379-384
Lactobacillus delbrueckii subsp. lactis, Lactobacillus plantarum, Lactococcus lactis subsp. lactis, Lactococcus plantarum, Listeria monocytogenes, Salmonella Typhimurium, coasts, fermentation, food safety, fruits, intestines, milk, pathogens, salmon, soymilk, storage temperature
A part of Lactobacillus plantarum and Lactococcus lactis subsp. lactis strains, isolated from coastal areas (Satoumi LAB) had shown acid, salt and bile resistances and good fermentation in soymilk rather than cow's milk. To prepare safer foods derived from fermented soymilk, Satoumi LAB strains were screened for antagonistic activity against Salmonella Typhimurium (ST) and Listeria monocytogenes (Lm) in brain heart infusion (BHI) broth. L. plantarum Tennozu-SU2 isolated from acorns showed 0.55 and 3.6 log CFU inhibitory effects against both ST and Lm, respectively. Six L. lactis strains suppressed 7 log CFU Lm. L. lactis BF1 isolated from salmon intestine also suppressed 0.95 log CFU ST. In a fermentation test, soymilk simultaneously inoculated with 6 or 7 log CFU/mL of ST or Lm, and 7 or 8 log CFU of Tennozu-SU2 or BF1 reduced Lm and ST counts by 2–6 log CFU/mL during 48 h fermentation. When soymilk fermented with Tennozu-SU2 or BF1 for 2 days and then inoculated with the pathogens, the counts of Lm and ST decreased during the 7 day storage at 10 °C, from 6 to 7 to 2–4 log CFU/mL. These results suggest that Tennozu-SU2 and BF1 are desirable as soymilk starters considering as they can improve food safety.