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Predictive models of the combined effects of curvaticin 13, NaCl and pH on the behaviour of Listeria monocytogenes ATCC 15313 in broth
Author(s) -
Bouttefroy A.,
Linder M.,
Millière J.B.
Publication year - 2000
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.2000.01053.x
Subject(s) - listeria monocytogenes , incubation , agar , bacteriocin , food science , microbiology and biotechnology , yeast extract , tryptic soy broth , listeria , strain (injury) , incubation period , chemistry , serotype , bacteria , biology , antimicrobial , biochemistry , fermentation , genetics , anatomy
Thirty‐three strains of Listeria monocytogenes belonging to different serotypes were tested for their sensitivity to curvaticin 13, an antilisterial bacteriocin produced by Lactobacillus curvatus SB13, using the well diffusion method in Institut Pasteur agar plates at 37 °C. No relationship between serotype and sensitivity was observed. The sensitivity of this species was strain‐dependent and a large variation in tolerance to curvaticin 13 was observed. The combined effects of curvaticin 13 (0–160 AU ml −1 ), NaCl (0–6% w/v), pH values (5·0–8·2) and incubation time (0–24 h) were investigated on L. monocytogenes ATCC 15313 in trypcase soy–yeast extract broth at 22 °C. For this study, two Doehlert matrices were used in order to investigate the main effects of these factors and their different interactions. The results were analysed using the Response Surface Methodology. Curvaticin 13 had a major inhibitory effect and the response was NaCl concentration‐, time‐ and pH‐dependent. This inhibitory activity was the same at pH values between 6·6 and 8·2. Curvaticin 13 was bactericidic at acidic pH values, but the surviving cells resumed growth. For a short incubation time (12 h), the effectiveness of curvaticin 13 was maximal in the absence of NaCl. For longer incubation times (12–48 h), with high NaCl (6%) and curvaticin 13 concentrations (160 AU ml −1 ), the inhibition of L. monocytogenes was greater than that observed with NaCl or curvaticin 13 alone.