Time-Kill Kinetics of Lipid Fractions Isolated from Condiments against Foodborne Pathogens

Lipidne frakcije izolirane iz začinskog bilja imaju širok spektar bioloških aktivnosti i često se koriste u medicinske svrhe ili pri kuhanju. Ovo je ispitivanje provedeno radi određivanja antimikrobnog potencijala lipidnih frakcija, izoliranih pomoću dvaju različitih sustava otapala, za suzbijanje rasta pet sojeva patogenih mikroorganizama prisutnih u hrani. Antibakterijska učinkovitost ispitana je nakon 0, 1, 2, 3 i 24 h inkubacije s aktivnom tvari. Istjecanje staničnog sadržaja mikroorganizama procijenjeno je nakon 1 i 2 sata inkubacije. Pretražnim elektronskim mikroskopom dobivene su slike stanica nakon 18 sati izlaganja minimalnim inhibicijskim koncentracijama lipidnih frakcija. Iz rezultata studije kinetike inhibicije rasta i istjecanja staničnog sadržaja zaključeno je da su lipidne frakcije imale najjači učinak na suzbijanje Gram-negativne bakterije Escherichia coli ATCC 8739 tijekom 3 i 1 sata inkubacije. Međutim, produljenjem vremena izlaganja aktivnoj tvari inhibiran je rast Gram-pozitivne bakterije Listeria monocytogenes ATCC 13932. Mikroskopske slike tretiranih mikroorganizama potvrdile su inhibicijski učinak odabranih lipidnih frakcija na sve ispitane patogene. Morfologija stanica bakterija potpuno je izmijenjena nakon 18 h inkubacije s lipidnim frakcijama. Rezultati ispitivanja potvrđuju znatan inhibicijski učinak lipidnih frakcija i narušavanje integriteta stanične stijenke bakterija nakon produljenog izlaganja aktivnoj tvari, što potvrđuje mogućnost uporabe ispitanih lipidnih frakcija u hrani.Lipid fractions that are extracted from condiments have a wide array of biological potential and are commonly utilized for medicinal and culinary applications. This investigation aims at determining the antimicrobial potential of lipid fractions isolated using two different solvent systems against five foodborne pathogens. The antibacterial efficacy was tested after 0, 1, 2, 3 and 24 h of incubation with the active agent. The leakage of cellular content was assessed at 1 and 2 h of incubation. Scanning electron microscope (SEM) images were obtained after 18 h of contact time with lipid fractions at their minimum inhibitory concentration (MIC). From the results obtained from time-kill and cell constituents release tests, it could be concluded that during 3 and 1 h of incubation, the lipid fractions were more potent against Gram-negative isolates (Escherichia coli ATCC 8739). However, prolonged incubation with the active agent inhibited Gram-positive isolate, i.e. Listeria monocytogenes ATCC 13932. SEM images of treated microorganisms also confirmed the inhibitory action of selected lipid fractions against all the tested pathogens. The cellular morphology of the bacteria was completely altered after 18 h of incubation with the lipid fractions. The results of the present study corroborate significant inhibitory effects and disruption in bacterial cell integrity following prolonged incubation with these lipid fractions. The results also affirm the use of the tested lipid fractions in food systems

Time-Kill Kinetics of Lipid Fractions Isolated from Condiments against Foodborne Pathogens

Lipid fractions that are extracted from condiments have a wide array of biological potential and are commonly utilized for medicinal and culinary applications. This investigation aims at determining the antimicrobial potential of lipid fractions isolated using two different solvent systems against five foodborne pathogens. The antibacterial efficacy was tested after 0, 1, 2, 3 and 24 h of incubation with the active agent. The leakage of cellular content was assessed at 1 and 2 h of incubation. Scanning electron microscope (SEM) images were obtained after 18 h of contact time with lipid fractions at their minimum inhibitory concentration (MIC). From the results obtained from time-kill and cell constituents release tests, it could be concluded that during 3 and 1 h of incubation, the lipid fractions were more potent against Gram-negative isolates (Escherichia coli ATCC 8739). However, prolonged incubation with the active agent inhibited Gram-positive isolate, i.e. Listeria monocytogenes ATCC 13932. SEM images of treated microorganisms also confirmed the inhibitory action of selected lipid fractions against all the tested pathogens. The cellular morphology of the bacteria was completely altered after 18 h of incubation with the lipid fractions. The results of the present study corroborate significant inhibitory effects and disruption in bacterial cell integrity following prolonged incubation with these lipid fractions. The results also affirm the use of the tested lipid fractions in food systems

Inactivation of Food Borne Pathogens by Lipid Fractions of Culinary Condiments and Their Nutraceutical Properties

Lipid fraction from four different culinary condiments namely black seed (Nigella sativa), fennel seeds (Foeniculum vulgare), bay leaf (Laurus nobilis) and coriander seeds (Coriandrum sativum) were investigated for total phenolic content, antioxidant activity, total flavonoid content, total flavonol content and antibacterial attributes. Antimicrobial properties were determined against food-borne bacteria through agar well diffusion, drop agar diffusion, macrobroth dilution with simultaneous determination of their minimum inhibitory concentrations and changes in cellular morphology was analyzed through Scanning electron microscopy. Generally, ethanolic lipid fractions were more effective bioactively as compared to methanolic LFs. Parallel results were obtained for antibacterial activities with the highest antibacterial activities exhibited by ethanolic LFs. The results positively support the use of these lipid fractions in generating new systems to inhibit bacterial growth, extend the shelf life and enhance the safety of the packaged food product. The examined oils can also be used for therapeutic purposes