The objective of this work was to evaluate the antimicrobial potential of different extracts of
Simira ecuadorensis, a characteristic plant of Ecuador, and to validate its potential as a food preservative.
Four extracts referred to as ethanol, ethanol-water (50:50 v/v), spray-dried, and freeze-dried were
obtained under different processes. Initially, their antimicrobial activities were evaluated against a
wide group of microorganisms consisting of 20 pathogenic and spoilage microbial strains found in
foods through the agar diffusion method. Then, the extracts with the best yields and antimicrobial
properties against microorganisms of greatest interest were selected to determine their effect on
model foods preserved under normal commercial conditions through challenge tests. Spray-dried
and ethanol-water extracts were tested for their ability to inhibit C. jejuni in chicken model products,
where is a common pathogen and Shew. putrefaciens in fish model products as it is a spoilage
microorganism frequently found in fish. One solid and one liquid were chosen as model foods:
burger and broth, respectively. Campylobacter jejuni and Shewanella putrefaciens were effectively
inhibited by the four extracts with minimum inhibitory concentration (MIC) of 80 mg/mL. Bacillus
cereus, Yersinia enterocolitica, Clostridium perfringens, and Leuconostoc mesenteroides were also inhibited
by ethanolic extract. The ethanol-water extract showed greater antimicrobial activity in fish products,
whereas spray-dried extract had low growth inhibition of C. jejuni in chicken burgers; however, it
was quite effective on C. jejuni in broth. The spray-dried extract significantly decreased the pH of the
chicken burgers, while the ethanolic extract had a slight impact on the pH of the fish burgers. The
presence of antibacterial effects revealed that the S. ecuadorensis extracts could be potentially used in
food preservation and as a natural antimicrobial.
