Universidade do Minho. Departamento de Engenharia Biológica (DEB)
Doi
Abstract
ICFC 2017 - International Conference on Food Contaminants (Book of Abstracts)Lactic acid bacteria (LAB) have been gaining attention for the antifungal properties of some
strains. The control of fungal growth is especially important since moulds are responsible
for significant spoilage of food and feed. Additionally, they are able t
o produce toxic
compounds known as mycotoxins that cause serious health hazards. Some LAB strains
have the ability to inhibit fungal growth and also the production of mycotoxins. In this
work, cell free supernatants (CFS) of
Lactobacillus plantarum
UM55 and
Lactobacillus
buchneri
UTAD104 were tested for the inhibition of
Penicillium nordicum
growth and
ochratoxin A (OTA) production. Fungal growth was inhibited in only 18 and 11% by CFS of
L. plantarum and L. buchneri, respectively. However, the production o
f OTA was reduced
approx. in 70% by both strains. In order to determine the nature of compounds responsible
for this activity, CFS were subjected to heat, proteases and neutralization of pH. It was
observed that CFS retained its inhibitory properties after
being autoclaved and treated with
proteases. However, when submitted to pH neutralization, CFS lost its activity. Some
organic acids produced by these LAB strains were also tested for their inhibitory capacity.
Calculation of inhibitory concentrations shown that butyric and propionic acids were the
most effective in inhibiting
P. nordicum
growth and OTA production, followed by indole
lactic acid (ILA), phenyllactic acid (PLA), acetic acid, hydroxyphenyllactic acid (OH-PLA)
and lactic acid. CFS were analysed by HPLC - PDA for the quantification of those organic
acids. For L. plantarum UM55 main differences were found in the levels of lactic acid, PLA,
OH-PLA, and ILA. For L. buchneri
UTAD104, levels of acetic, lactic and PLA were higher
than in the control experiment. In conclusion, ability of LAB to inhibit mycotoxigenic fungi
depends of strain capability to produce certain organic acids, and those acids may differ from strain to straininfo:eu-repo/semantics/publishedVersio
