Original Research Article
Year: 2017 | Month: December | Volume: 7 | Issue: 12 | Pages: 187-192
The Influence of Instant Coffee on the Survival Rate of Lactobacillus Acidophilus, Bifidobacterium Bifidum, Escherichia Coli and Staphylococcus Aureus
Márcia Aparecida Caires Ribeiro1, Claudia Dorta1, Alice Yoshiko Tanaka1, Elke Shigematsu1,
Juliana Audi Giannoni1, Renata Bonini Pardo1
1Faculty of Food Technology of Marilia (FATEC), Av. Castro Alves, 62, Marilia 17506-000, SP, Brazil
Corresponding Author: Márcia Aparecida Caires Ribeiro
ABSTRACT
Some studies show that the bioactive substances found in coffee may act as prebiotics while others may have an antibacterial effect, including on virulent genera for humans. This work verified the influence in vitro of instant coffee on the survival rate of two probiotic bacteria: Lactobacillus acidophilus and Bifidobacterium bifidum, and two potentially pathogenic species: Staphylococcus aureus and Escherichia coli. Commercial instant coffee was used as a reaction medium, adjusted to a pH of 6.0 and 7.5. The control tests were made in MRS broth for the probiotic bacteria and BHI broth for S. aureus and E. coli, medium components of PCA without agar. The survival rate (SR) was calculated through the relationship between the cell viability with the treatments and their respective controls. The experiments were done in aseptic conditions and in triplicate, and their data were submitted to statistical analysis. In pH 6.0, the instant coffee medium significantly decreased the survival rate (SR = 84%) of S. aureus compared to the other bacteria, but L. acidophilus (SR = 101%) showed a growth trend only in one hour of reaction. In pH 7.5, the instant coffee medium also showed a higher survival rate (99.5%) for L. acidophilus. B. bifidum and E. coli, which had a low sensibility to the coffee medium, not suffering significant interference with the pH variation. The instant coffee medium (in both pH tested) interfered positively or negatively with the SR, in different ways, for each bacterium under study.
Key words:Coffee – probiotic – gate – inhibition – stimulus