Alberto Gonçalves Evangelista
◽
Jessica Audrey Feijó Corrêa
◽
João Vitor Garcia dos Santos
◽
Eduardo Henrique Custódio Matté
◽
Mônica Moura Milek
◽
...
The genus
Salmonella
is closely associated with foodborne outbreaks and animal diseases, and reports of antimicrobial resistance in
Salmonella
species are frequent. Several alternatives have been developed to control this pathogen, such as cell-free supernatants (CFS). Our objective here was to evaluate the use of lactic acid bacteria (LAB) CFS against Salmonella in vitro. Seventeen strains of LAB were used to produce CFS, and their antimicrobial activity was screened towards six strains of
Salmonella
. In addition, CFS were also pH-neutralized and/or boiled. Those with the best results were lyophilized. MICs of lyophilized CFS were 11.25–22.5 g l–1. Freeze-dried CFS were also used to supplement swine and poultry feed (11.25 g kg–1) and in vitro simulated digestion of both species was performed, with
Salmonella
contamination of 5×106 and 2×105 c.f.u. g−1 of swine and poultry feed, respectively. In the antimicrobial screening, all acidic CFS were able to inhibit the growth of
Salmonella
. After pH neutralization,
Lactobacillus acidophilus
Llorente,
Limosilactobacillus fermentum
CCT 1629,
Lactiplantibacillus plantarum
PUCPR44,
Limosilactobacillus reuteri
BioGaia,
Lacticaseibacillus rhamnosus
ATCC 7469 and
Pediococcus pentosaceus
UM116 CFS were the only strains that partially maintained their antimicrobial activity and, therefore, were chosen for lyophilization. In the simulated swine digestion,
Salmonella
counts were reduced ≥1.78 log c.f.u. g–1 in the digesta containing either of the CFS. In the chicken simulation, a significant reduction was obtained with all CFS used (average reduction of 0.59±0.01 log c.f.u. ml–1). In general, the lyophilized CFS of
L. fermentum
CCT 1629,
L. rhamnosus
ATCC 7469 and
L. acidophilus
Llorente presented better antimicrobial activity. In conclusion, CFS show potential as feed additives to control
Salmonella
in animal production and may be an alternative to the use of antibiotics, minimizing problems related to antimicrobial resistance.
In Vitro Evaluation of Antimicrobial Activity of Lactic Acid Bacteria against Clostridium difficile
