Antimicrobial activity of ethanol extracts of Sambucus canadensis, Bidens alba, Ricinus communis and Salvia microphylla against foodborne pathogens

Bacteria that compromise food safety cause serious diseases globally, with a higher recurrence in developing countries. This has underscored the need to explore effective antimicrobial alternatives. This study aimed to evaluate the antimicrobial activity of ethanolic extracts from Sambucus canadensis, Bidens alba, Ricinus communis and Salvia microphylla against Gram-positive and Gram-negative bacteria through both in vitro and in vivo tests. Phytochemical analyses and functional group identification using IR spectroscopy were performed. In vitro testing utilized disk diffusion and microplate techniques, while in vivo testing involved Solanum lycopersicum to assess microbial loads within the maximum allowable limit (MAL) according to the Official Mexican Standard NOM-093-SSA1-1994. Phytochemical and IR analyses confirmed the presence of flavonoids, terpenes, and saponins, all of which are known to possess antimicrobial properties. Overall, all extracts inhibited both Gram-positive and Gram-negative bacteria. Notably, the extracts of S. canadensis and B. alba exhibited the largest zones of inhibition, which were statistically significant (P<0.05) compared to the other extracts and the control. Minimum inhibitory concentration (MIC) values ranged from 68.1 to 1000 µg mL-1, with the Sambucus canadensis extract showing the greatest inhibition against Staphylococcus aureus and Klebsiella pneumoniae at 68.1 and 75.1 µg mL-1, respectively. In vivo tests demonstrated that all extracts reduced the bacterial load of the evaluated strains, except for Salmonella typhimurium. These findings suggest that the evaluated extracts could be a promising alternative for natural antimicrobials against foodborne pathogens that threaten food safety and human health.