Determinación del potencial bactericida In vitro de un aislado nativo de Lactobacillus cassei frente E. coli
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Date
2008
Journal Title
Journal ISSN
Volume Title
Publisher
Corporación Universitaria Lasallista
Abstract
Introduction. Probiotics are living microorganisms
with a great capacity against other microorganisms,
this is why there is an interest in using them as natural
bio-preservatives, reducing partially the use of
chemical preservatives in food. Objective. To determine
the bactericide effect of the raw extract of native
L. cassei on the in Vitro growth of pathogenic bacteria,
such as E.coli. Materials and methods. The raw
extract was obtained by cultivating the microorganism
in 20 ml of MRS breeding ground at 37 ºC Turing 72
h, anaerobically. The experiments were done in three
periods of time: 5, 10 and 15 days. The method used
to detect the activity of the extract was the experiment
of diffusion in wells. Those that represented an
inhibition halo above 2mm were considered as active.
The results found were compared with those from
a strain of Lactobacillus plantarum of for commercial
use with a bactericide activity against Escherichia coli.
Results. L.cassei represented hostile activity against
E.coli, because the inhibition zones read as response
variable were higher than 2mm until getting the 10-3
dilution in the three experiments made. However, on
day 15 the bactericide activity of the extract was
considerably reduced when compared to that from
day 5. The analysis of activity units showed that the
extract from this isolated is active even in high
dilutions, which means that the extracts are active
even at very low concentrations. Conclusion. The
native isolated of L.cassei produces antimicrobials
against Gram negative bacteria, such as E.coli, being available for their possible use as natural bio
preservatives in food.
Description
Keywords
Corporación Universitaria Lasallista, Probióticos, E.Coli, Lactobacillus cassei, Prebióticos, Bactericida