Growth dynamics of foodborne pathogens in response to chemical and plant-derived antimicrobial agents

Foodborne pathogens pose serious risks to food safety and public health, driving interest in effective antimicrobial strategies. Plant-based extracts have been proposed as sustainable alternatives to synthetic agents. This study evaluated the antimicrobial efficacy of benzalkonium chloride (BAC) and seed extracts from black seed (Nigella sativa), black pepper (Piper nigrum), and cardamom (Elettaria cardamomum) against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. Antimicrobial activity was assessed using minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), agar well diffusion assays, plant extraction techniques, and dynamic growth monitoring with the bacterial growth kinetics (BioScreen C system). BAC exhibited strong, concentration-dependent antimicrobial activity, with Gram-positive bacteria showing the highest susceptibility (MIC/MBC: 0.00003125–0.0000625%). Gram-negative bacteria were more resistant, requiring higher BAC concentrations for inhibition. Plant extracts showed limited efficacy; only cardamom inhibited S. aureus and partially inhibited E. coli. Overall, BAC demonstrated superior effectiveness, supporting its continued use in food safety control systems.