Effect of Essential Oils on Multidrug Resistant Gram-Negative Bacteria

Abstract

Obtaining healthy food, free from chemical or synthetic additives, is a major challenge. In this study, we developed a preservation method using essential oils and evaluated their effect on multidrug resistant pathogenic Gram-negative bacteria. Different concentrations (1%,0.1%,0.17% and 0.35%) of Thyme oil and black seed oil were employed in this study against pathogenic E. coli and A. hydrophila in soft cheese. The used oils at a concentration of 0.1% through dipping method resulted in accepted color and odor, little effect on flavor and normal texture and appearance, while 0.1% during inoculation had the same effect as in dipping method except moderate odor. Thyme oil had the highest reduction rate in case of 1% dipping and 0.17% inoculation on A. hydrophila, while against E. coli it was found that 0.17% inoculation and 0.35% of the dipping method had the highest reduction effect. Thyme essential oil seems to be a suitable natural food preservative alternative.

Beyond Chemical Preservatives: Enhancing the Shelf-Life and Sensory Quality of Ready-to-Eat (RTE) Hummus with Vinegar and Other Natural Antimicrobials

“…Furthermore, the addition of 0.5%-1.5% thyme essential oil to hummus decreased Salmonella by 1.0-2.9 log CFU/g at 4 • C over the course of 10 days [75]. It was also shown that using 0.17% and 0.35% thyme oil had a great effect in controlling E. coli when added to soft cheese [76]. Another study showed that the combination of antimicrobials like 1% garlic and 0.5% chitosan in hummus was able to reduce Salmonella, E. coli O157:H7, and L. monocytogenes by 0.7-2.5, 0.6-2.2, and 1.0-1.5 log CFU/g, respectively [44].…”

Genetic Characterization of Multi Drug Resistant Staphylococcus Spp. in Raw Milk and Karish cheese

“…Staph aureus isolates were confirmed as coagulase positive (CPS) in this study meanwhile, NAS strains were reported in Figure (1) of which some exhibited coagulase negative activity (CNS). This group of CNS could constitute serious threat for both animal and human health since CNS were associated with several cases of subacute and chronic mastitis in dairy animals (Makkia et al 2022) The discrepancies in the prevalence ratio Staphylococcus spp. in dairy animals could be attributed to the fact that mammary gland of these animals are the main reservoir for those pathogens especially in animals with clinical or subclinical mastitis.…”