A conductance-based surface disinfection test for food hygiene

Holah, John; Higgs, Charlie; Robinson, Sandra; Worthington, David; Spenceley, H.

doi:10.1111/j.1472-765x.1990.tb00175.x

Cited by 100 publications

(52 citation statements)

References 9 publications

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“…We proposed that the reduction of bacterial adhesion by NAC is a chemical and biological effect. Information concerning the effect of antiadhesive coatings on the bacterial status of equipment and devices is conventionally obtained by direct methods that remove bacteria from the surface by swabbing or sonication and determine bacterial numbers by agar plating (45) or direct counting using epifluorescence microscopy (18,51). Since none of these techniques reveal the actual interaction of bacteria with the surface, it has been difficult, if not impossible, to learn more about how the coatings affect the binding between bacteria and surfaces.…”

Section: Discussionmentioning

confidence: 99%

Use of a Quartz Crystal Microbalance To Investigate the Antiadhesive Potential of N -Acetyl- l -Cysteine

Olofsson

Hermansson

Elwing

2005

Appl Environ Microbiol

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The reduction of bacterial biofilm formation on stainless steel surfaces by N-acetyl-L-cysteine (NAC) is attributed to effects on bacterial growth and polysaccharide production, as well as an increase in the wettability of steel surfaces. In this report, we show that NAC-coated stainless steel and polystyrene surfaces affect both the initial adhesion of Bacillus cereus and Bacillus subtilis and the viscoelastic properties of the interaction between the adhered bacteria and the surface. A quartz crystal microbalance with dissipation was shown to be a powerful and sensitive technique for investigating changes in the applied NAC coating for initial cell surface interactions of bacteria. The kinetics of frequency and dissipation shifts were dependent on the bacteria, the life cycle stage of the bacteria, and the surface. We found that exponentially grown cells gave rise to a positive frequency shift as long as their cell surface hydrophobicity was zero. Furthermore, when the characteristics of binding between the cell and the surface for different growth phases were compared, the rigidity increased from exponentially grown cells to starved cells. There was a trend in which an increase in the viscoelastic properties of the interaction, caused by the NAC coating on stainless steel, resulted in a reduction in irreversibly adhered cells. Interestingly, for B. cereus that adhered to polystyrene, the viscoelastic properties decreased, while there was a reduction in adhered cells, regardless of the life cycle stage. Altogether, NAC coating on surfaces was often effective and could both decrease the initial adhesion and increase the detachment of adhered cells and spores. The most effective reduction was found for B. cereus spores, for which the decrease was caused by a combination of these two parameters.Bacteria commonly adhere to a surface and are part of a complex biofilm. Since the growth of biofilms causes enormous economic losses and health problems in industrial systems like food and paper production, huge efforts are made to solve this problem. The adhesion of bacteria to surfaces is a complex interplay of physical, chemical, and biological factors (5), and there are large variations in the adhesion behaviors of different bacteria and also for different life cycle stages of one strain (41). It is very important to consider these differences when antiadhesion coatings are developed. It is generally thought that bacterial adhesion is preceded by the adsorption of a conditioning layer of molecules that influence adhesion of bacteria to surfaces (43). A good antiadhesion coating should form a conditioning film that prevents adhesion and has a low cohesive strength, making a weak bond between the biofilm and the surface (6). One such agent may be N-acetyl-L-cysteine (NAC). NAC is commonly used in medical treatment of chronic bronchitis and cancer (38,46) and is one of the smallest drug molecules in use (30). Moreover, we recently demonstrated that NAC affects several processes that are important for bacterial biofilm fo...

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Section: Discussionmentioning

confidence: 99%

Use of a Quartz Crystal Microbalance To Investigate the Antiadhesive Potential of N -Acetyl- l -Cysteine

Olofsson

Hermansson

Elwing

2005

Appl Environ Microbiol

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“…Some researchers have calculated the number of cells on stainless steel surfaces by relating the TTD to the equivalent number of cells, indicated by a standard calibration curve prepared from serial dilutions of planktonic cells [37,38]. Other studies of surface-inhabiting bacteria have also used calibration curves constructed from planktonic cell suspensions [39][40][41].…”

Section: Disinfection Efficacy Of Hssp Against E Coli Biofilm Estimmentioning

confidence: 99%

Disinfection Treatment of Heated Scallop-Shell Powder on Biofilm of <i>Escherichia coli</i> ATCC 25922 Surrogated for <i>E. coli</i> O157:H7

Kubo¹,

Ohshima²,

Irie³

et al. 2013

JBNB

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The ability of heated scallop-shell powder (HSSP) to disinfect Escherichia coli ATCC 25922 biofilm was investigated. On account of its cryotolerance and cell surface characteristics, the E. coli strain is reportedly a useful surrogate for E. coli O157: H7 in surface attachment studies. In this study, an E. coli ATCC 25922 biofilm was formed on a glass plate, and immersed in a slurry of HSSP. Following treatment, the disinfection ability of the HSSP toward the biofilm was non-destructively and quantitatively measured by conductimetric assay. The disinfection efficacy increased with HSSP concentration and treatment time. HSSP treatment (10 mg/mL, pH 12.5) for 20 min completely eliminated biofilm bioactivity (approximately 10 8 CFU/cm 2 in non-treated biofilms). In contrast, treatment with NaOH solution at the same pH, and treatment with sodium hypochlorite (200 g/mL) reduced the activity by approximately one to three log 10 . Fluorescence microscopy confirmed that no viable cells remained on the plate following HSSP treatment (10 mg/mL). Although alkaline and sodium hypochlorite treatments removed cells from the biofilm, under these treatments, many viable cells remained on the plate. To elucidate the mechanism of HSSP activity against E. coli ATCC 25922, the active oxygen generated from the HSSP slurry was examined by chemiluminescence analysis. The luminescence intensity increased with increasing concentration of HSSP slurry. The results suggested that, besides being alkaline, HSSP generates active oxygen species with sporicidal activity. Thus, HSSP treatment could also be effective for controlling biofilms of the toxic strain E. coli O157: H7, implicated in food poisoning.

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“…It has been shown that NaCl concentration, pH, lipid content and agar concentration affect the diffusion of different bacteriocins in an agar matrix (2). It has also been demonstrated that bacteria attached to surfaces are more resistant to disinfectants than free-living bacteria are (7,10). Williams et al (25,26) concluded that an increase in the antibiotic resistance of attached Staphylococcus aureus was due to significant physiological adaptation that occurred during the early phases of attached growth.…”

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confidence: 99%

Real-Time Measurements of the Interaction between Single Cells of Listeria monocytogenes and Nisin on a Solid Surface

Budde

2000

Appl Environ Microbiol

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A method to obtain real-time measurements of the interactions between nisin and single cells of Listeria monocytogenes on a solid surface was developed. This method was based on fluorescence ratio-imaging microscopy and measurements of changes in the intracellular pH (pH i ) of carboxyfluorescein succinimidyl esterstained cells during exposure to nisin. Immobilized cells were placed in a chamber mounted on a microscope and attached to a high-precision peristaltic pump which allowed rapid changes in the nisin concentration. In the absence of nisin, the pH i of L. monocytogenes was almost constant (approximately pH 8.0) and independent of the external pH in the pH range from 5.0 to 9.0. In the presence of nisin, dissipation of the pH gradient (⌬pH) was observed, and this dissipation was both time and nisin concentration dependent. The dissipation of ⌬pH resulted in cell death, as determined by the number of CFU. In the model system which we used the immobilized cells were significantly more resistant to nisin than the planktonic cells. The kinetics of ⌬pH dissipation for single cells revealed a variable lag phase depending on the nisin concentration, which was followed by a very rapid decrease in pH i within 1 to 2 min. The differences in nisin sensitivity between single cells in a L. monocytogenes population were insignificant for cells grown to the stationary phase in a liquid laboratory substrate, but differences were observed for cells grown on an agar medium under similar conditions, which resulted in some cells having increased resistance to nisin.Food preservation techniques which include the application of bacteriocin-producing lactic acid bacteria or purified bacteriocins have been studied extensively in order to increase the control of Listeria monocytogenes in particular in foods such as meat products and cheeses (11,13,14,17,19). The best-known and best-studied bacteriocin is the nisin produced by Lactococcus lactis (6, 9). Nisin acts on the cytoplasmic membrane of sensitive cells particularly L. monocytogenes, where it forms pores that lead to dissipation of the membrane potential and the pH gradient (⌬pH) and subsequent collapse of the proton motive force (1,4,27).Most food products of interest in biopreservation are often solid or semisolid, and the probability that bacteriocins will reach the target organism depends on the nature of the food matrix. It has been shown that NaCl concentration, pH, lipid content and agar concentration affect the diffusion of different bacteriocins in an agar matrix (2). It has also been demonstrated that bacteria attached to surfaces are more resistant to disinfectants than free-living bacteria are (7, 10). Williams et al. (25,26) concluded that an increase in the antibiotic resistance of attached Staphylococcus aureus was due to significant physiological adaptation that occurred during the early phases of attached growth.To what extent the solid food matrix influences the probability that bacteriocins will reach the target cells and to what extent the resistance to ...

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A conductance-based surface disinfection test for food hygiene

Cited by 100 publications

References 9 publications

Use of a Quartz Crystal Microbalance To Investigate the Antiadhesive Potential of N -Acetyl- l -Cysteine

Use of a Quartz Crystal Microbalance To Investigate the Antiadhesive Potential of N -Acetyl- l -Cysteine

Disinfection Treatment of Heated Scallop-Shell Powder on Biofilm of <i>Escherichia coli</i> ATCC 25922 Surrogated for <i>E. coli</i> O157:H7

Real-Time Measurements of the Interaction between Single Cells of Listeria monocytogenes and Nisin on a Solid Surface

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A conductance-based surface disinfection test for food hygiene

Cited by 100 publications

References 9 publications

Use of a Quartz Crystal Microbalance To Investigate the Antiadhesive Potential of N -Acetyl- l -Cysteine

Use of a Quartz Crystal Microbalance To Investigate the Antiadhesive Potential of N -Acetyl- l -Cysteine

Disinfection Treatment of Heated Scallop-Shell Powder on Biofilm of &lt;i&gt;Escherichia coli&lt;/i&gt; ATCC 25922 Surrogated for &lt;i&gt;E. coli&lt;/i&gt; O157:H7

Real-Time Measurements of the Interaction between Single Cells of Listeria monocytogenes and Nisin on a Solid Surface

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Disinfection Treatment of Heated Scallop-Shell Powder on Biofilm of <i>Escherichia coli</i> ATCC 25922 Surrogated for <i>E. coli</i> O157:H7