Advances in disinfection testing and modelling

Lambert, R. H.

doi:10.1046/j.1365-2672.2001.01393.x

Cited by 32 publications

(44 citation statements)

References 24 publications

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“…The interaction affects membrane permeability, and this has been documented by loss of membrane potential, cellular uptake of ethidium bromide, and leakage of potassium ions, ATP, and carboxyfluorescein (Helander et al, 1998; Lambert et al, 2001; Walsh et al, 2003; Xu et al, 2008). Although the protective properties of lipopolysaccharide (LPS) against thymol had been confirmed using random transposon-insertion mutants, treatment of E. coli cells with thymol caused release of LPS and disruption of the outer membrane (Helander et al, 1998; Shapira and Mimran, 2007).…”

Section: Essential Oil Constituent Classes: Their Antimicrobial Activmentioning

confidence: 99%

Essential Oils in Food Preservation: Mode of Action, Synergies, and Interactions with Food Matrix Components

Hyldgaard¹,

Mygind²,

Meyer³

2012

Front. Microbio.

1,628

1,073

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Essential oils are aromatic and volatile liquids extracted from plants. The chemicals in essential oils are secondary metabolites, which play an important role in plant defense as they often possess antimicrobial properties. The interest in essential oils and their application in food preservation has been amplified in recent years by an increasingly negative consumer perception of synthetic preservatives. Furthermore, food-borne diseases are a growing public health problem worldwide, calling for more effective preservation strategies. The antibacterial properties of essential oils and their constituents have been documented extensively. Pioneering work has also elucidated the mode of action of a few essential oil constituents, but detailed knowledge about most of the compounds’ mode of action is still lacking. This knowledge is particularly important to predict their effect on different microorganisms, how they interact with food matrix components, and how they work in combination with other antimicrobial compounds. The main obstacle for using essential oil constituents as food preservatives is that they are most often not potent enough as single components, and they cause negative organoleptic effects when added in sufficient amounts to provide an antimicrobial effect. Exploiting synergies between several compounds has been suggested as a solution to this problem. However, little is known about which interactions lead to synergistic, additive, or antagonistic effects. Such knowledge could contribute to design of new and more potent antimicrobial blends, and to understand the interplay between the constituents of crude essential oils. The purpose of this review is to provide an overview of current knowledge about the antibacterial properties and antibacterial mode of action of essential oils and their constituents, and to identify research avenues that can facilitate implementation of essential oils as natural preservatives in foods.

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Section: Essential Oil Constituent Classes: Their Antimicrobial Activmentioning

confidence: 99%

Essential Oils in Food Preservation: Mode of Action, Synergies, and Interactions with Food Matrix Components

Hyldgaard¹,

Mygind²,

Meyer³

2012

Front. Microbio.

1,628

1,073

View full text Add to dashboard Cite

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“…The antifungal mechanism of action by which thymol or carvacrol acts is not well understood although membrane and cell wall disruption with morphological deformation, collapse and deterioration of the conidia and/or hyphae have been hypothesized (Lambert, 2001;Neri et al, 2005). On the other hand, Ultee et al (2002) hypothesized that the hydroxyl group and the presence of a system of delocalized electrons are important for the antimicrobial activity of phenolic compounds, such as carvacrol and thymol.…”

Section: Concentration (µL L -1 )mentioning

confidence: 99%

The effects of essential oils carvacrol and thymol on growth of Penicillium digitatum and P. italicum involved in lemon decay

Pérez-Alfonso

Martı́nez-Romero

Zapata

et al. 2012

International Journal of Food Microbiology

138

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“…To make certain that the true mechanism of the reaction is synergistic, the values of 2f(a) and 2f(b) should also be determined and compared with the value of f(a + b), and show that 2f(a) > f(a + b) and 2f(b) > f(a + b). The concept of synergism and the correct means for determining whether the effect is synergistic, additive, or antagonistic has been described in several reviews on this subject (28,30), and papers on its applications to various agents (31-33), theoretical treatment, and modeling (34)(35)(36).…”

Section: Synergismmentioning

confidence: 99%

Synergistic reaction of silver nitrate, silver nanoparticles, and methylene blue against bacteria

Chen

Cesario

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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In this paper we describe the antibacterial effect of methylene blue, MB, and silver nitrate reacting alone and in combination against five bacterial strains including Serratia marcescens and Escherichia coli bacteria. The data presented suggest that when the two components are combined and react together against bacteria, the effects can be up to three orders of magnitude greater than that of the sum of the two components reacting alone against bacteria. Analysis of the experimental data provides proof that a synergistic mechanism is operative within a dose range when the two components react together, and additive when reacting alone against bacteria.bacteria | synergistic effect | methylene blue | silver ions B acterial infections cause countless deaths in humans and animals. The increasing resistance and immunity of many bacteria to antibiotics demands that an effective means for the inactivation of bacteria becomes available that can overcome or negate the mechanism that bacteria use to inactivate the reactive agents before they render their lethal action on those organisms. The two antibacterial agents that we used in this study were methylene blue (MB) and silver nitrate. Each of these alone is known to be an effective antibacterial agent. The data presented in this study show that they make a synergistic agent pair against the five bacteria studied. MB is used as a bacterial inactivator for skin treatment, dental therapy, and other areas in need of bacterial disinfection (1-3). MB is a cation, whereas in its reduced leuco form MB has a pK a of 5.8 and low ionization at neutral physiological pH. This enables bacteria to reduce and inactivate MB to the leuco form. In fact, the discoloration of MB has been an indication of the presence of bacteria. In its cationic form, MB irradiated with 630-680-nm light is used for cancer therapy and as an effective bactericidal and activating agent. MB is an effective antibacterial agent owing to its ability to generate a high concentration of singlet oxygen, 1 O 2 ( 1 Δ g ), and other reactive oxygen species, such as OH • radicals (ROS), when irradiated with red light, which in contrast to UV light does not harm humans or animals cells. Therefore, the MB bacterial inactivation process is very safe and effective owing to the high reactivity of ROS with bacterial outer-cell membrane. It is found that the photogenerated singlet oxygen reacts against tryptophan and other outer-membrane molecules, resulting in damage to the bacterial cell and inhibiting protein production. ROS may also create a hole in the bacterial cell wall, which allows MB radicals to penetrate through the bacterial membrane and attack DNA, forming dimers which prevent it from replicating and consequently induce bacterial inactivation. The photoreaction that generates singlet oxygen and OH • radicals proceeds as follows: i) MB in water solution is excited to the first singlet state MB*:MB + hν (660 nm) →MB*; ii) MB* decays to the triplet state 3 MB* with a lifetime of ∼10 −9 s: MB* → 3 MB*; iii) The tripl...

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Advances in disinfection testing and modelling

Abstract: The fat equations are an improvement over commonly-used rate models of disinfection, which are shown to be special cases of these equations. This raises the question as to whether our current understanding of the kinetic basis of disinfection requires revision.

Cited by 32 publications

References 24 publications

Essential Oils in Food Preservation: Mode of Action, Synergies, and Interactions with Food Matrix Components

Essential Oils in Food Preservation: Mode of Action, Synergies, and Interactions with Food Matrix Components

The effects of essential oils carvacrol and thymol on growth of Penicillium digitatum and P. italicum involved in lemon decay

Synergistic reaction of silver nitrate, silver nanoparticles, and methylene blue against bacteria

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