Plectranthus amboinicus (Lour.) Spreng. essential oil as a natural alternative for the conservation of beef patties stored under refrigeration

Abstract

Plectranthus amboinicus essential oil (PAEO) has the potential to be used by the food industry as a natural antimicrobial alternative. The study aimed to evaluate the antibacterial activity of PAEO in vitro against pathogenic bacteria contaminating food and its potential for action when added to intentionally contaminated beef patties. The composition was determined by GC-MS and GC-FID, and thymol (45.64%) was the main compound present in the PAEO. The minimum inhibitory (MIC) and minimum bactericidal (MBC) concentration of the PAEO was evaluated against five pathogenic bacteria (Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Pseudomonas aeruginosa and Salmonella Typhimurium). The MIC of PAEO was the concentration ranges between 0.25 and 2 mg mL −1, and the MBC ranged from 1 to 4 mg mL −1. The anti-adhesion and removal of adhered cell assays indicated significant reductions (P < 0.05) even at concentrations 8x lower than the MIC of PAEO. Beef patties samples were prepared with PAEO concentrations at MIC (2 mg mL −1) and sub-MIC (1 mg mL −1). L. monocytogenes and E. coli were inoculated individually into the beef patties. Significant reductions were observed with a greater reduction in the 12th day of storage for L. monocytogenes (1.52 log CFU.g −1) and E. coli (0.93 log CFU.g −1) for beef patties with the MIC of PAEO. PAEO has the potential to be applied in meat products. However, the application and interactions of the oil in the food matrix need to be better elucidated.