Percorrer por autor "Barracosa, R."
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- Antimicrobial activity of organic acids against some common food spoilage and pathogenic microorganismsPublication . Sorathiya, K.; Melo, A.; Rodrigues, C.; Paulico, L.; Barracosa, R.; Correia, D.; Pintado, M.Background: In recent years, the food industry is challenged to produce high-quality products using natural preservative alternatives instead of synthetic ones, owing to the increasing consumer demand for clean-label food products. Organic acids have potential as an alternative due to their antimicrobial activity and high food safety (GRAS). Therefore, the objective of this work was to investigate the antimicrobial activity of organic acids against some common food spoilage and pathogenic microorganisms for use in food formulation. Method: The antimicrobial activity of the organic acids (lactic, citric, and propionic acid) was tested at different concentrations ranging from 0.06 to 4% by microdilution method in 96 well plates against Lactobacillus plantarum, Escherichia coli; Candida intermedia, Pichia fermentans, Penicillium glabrum, and Aspergillus niger. The minimum inhibitory concentration (MIC) was recorded as the lowest concentration at which complete inhibition of visible growth occurred. Results: The MICs of lactic, citric, and propionic acid for E. coli were 0.25, 0.25, and 0.125% respectively, while for L. plantarum, they were 0.25, 0.25, and 0.06% respectively. Regarding the yeasts, the MIC of lactic, citric, and propionic acid for C. intermedia were 1, 2, and 0.125%, respectively and for P. fermentans they were 1, 0.5, and 0.5%, respectively. Propionic acid also shows fungicidal potential against A. niger and P. glabrum with MIC values 0.5 and 0.25, respectively. Lactic acid displayed a MIC value of 4% representing the highest MIC value observed for both, while citric acid did not inhibit these fungi. Conclusion: The organic acids tested showed significant antimicrobial potential at low concentrations, particularly lactic and propionic acids. Future studies will incorporate the most promising acids as substitutes for synthetic preservatives to verify their ability to maintain antimicrobial effectiveness over time when incorporated into foods.
- Antimicrobial activity of potential essential oils to replace potassium sorbate in fruit preparationsPublication . Melo, A.; Sorathiya, K.; Rodrigues, C.; Paulico, L.; Barracosa, R.; Pintado, M.Introduction: In recent years, the food industry has faced the challenge of producing high-quality products using natural preservative alternatives instead of synthetic ones. Essential oils (EO), naturally present in various plants, have potential as alternatives due to their antimicrobial activity and high food safety (Generally Recognized as Safe, GRAS). This study aimed to investigate the antimicrobial activity of EO against common spoilage and pathogenic microorganisms in fruit preparations, to use as a substitute for potassium sorbate (PS). Methodology: The antimicrobial activity of lemongrass and lemon EO was tested using the microdilution method in 96-well plates against Lactobacillus plantarum, Escherichia coli; Candida intermedia, Pichia fermentans, Aspergillus niger and Penicillium glabrum.EO were tested at concentrations ranging from 1.56 to 50% and PS at 0.03 to 4%. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. Results: The MICs of lemongrass and lemon EO for E. coli were 3.12 and 12.5%, respectively, while for L. plantarum, they were 1,56 and 6.25% respectively. Regarding the yeasts, the MIC of lemongrass and lemon EO for C. intermedia were 1.56 and 3.12%, respectively, and for P. fermentans, they were 1.56 and 1.56%, respectively. Lemongrass EO showed the same MICs value of 6.25% against A. niger, and P. glabrum. Lemon EO also displayed the same MICs values of 25% for A. niger, and P. glabrum representing the highest MICs values observed. The MBCs values was similar the MICs values to all microorganisms except to L. plantarum that were 6.25 and 25% to lemongrass and lemon EO, respectively. PS showed MICs values of 1 and 2% for E. coli and L. plantarum, respectively, with MBCs values of 2% for both. For yeasts, the MIC was 0.06% for both with MBC values of 0.06% for E. coli and 0.5% for L. plantarum. The MIC and MBC values were the same of 0.06% for both fungi. Conclusion: The EO tested showed significant antimicrobial potential at low concentrations, particularly lemongrass EO. Future studies will incorporate this oil as substitutes for PS to verify their ability to maintain antimicrobial effectiveness over time when incorporated in fruit preparations.