Influence of Environmental Stress on the Kinetics and Strength of Attachment of Listeria monocytogenes Scott A to Buna-N Rubber and Stainless Steel

1998 ◽  
Vol 61 (10) ◽  
pp. 1286-1292 ◽  
Author(s):  
L. MICHELE SMOOT ◽  
MERLE D. PIERSON
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Growth Temperature ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Model Systems ◽  
Test Surface ◽  
Alkaline Conditions ◽  
Temperature And Growth ◽  
Growth Ph

Attachment and detachment of Listeria monocytogenes Scott A to Buna-N rubber and stainless Steel under varying conditions of temperature and pH were investigated using model systems. Numbers of attached cells increased with increasing attachment temperature (10 to 45°C) and time (up to 120 min) for both test surfaces. Compared to Buna-N rubber, the rate of attachment to stainless Steel was markedly more rapid for all temperature and pH conditions studied and could not be calculated. Rate of attachment to Buna-N rubber was found to be significantly lower when cells were attached at 10°C. Growth temperature did not significantly affect rates of adhesion to Buna-N rubber. Altering the medium pH during attachment between 4 and 9 demonstrated that rates of adhesion were slower under alkaline conditions. Growth pH was also found to significantly affect rates of attachment to Buna-N rubber. Detachment of cells adhered to Buna-N rubber was significantly affected by growth temperature but not growth pH. Significant differences in detachment were also found between Buna-N rubber and stainless Steel, inferring stronger attachment to Buna-N rubber. Cell surface hydrophobicity was found to be affected by both growth temperature and growth pH. However, changes in hydrophobicity could not be correlated to differences in rates of attachment. Addition of 0.01% trypsin to the attachment medium during cell exposure to either test surface resulted in a 99.9% reduction in the adhered cell population when compared to Controls. This would suggest that proteins play a role in the initial attachment process of L. monocytogenes.

scholarly journals Effect of Environmental Stress on the Ability of Listeria monocytogenes Scott A To Attach to Food Contact Surfaces

1998 ◽  
Vol 61 (10) ◽  
pp. 1293-1298 ◽  
Author(s):  
L. MICHELE SMOOT ◽  
MERLE D. PIERSON
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Cell Growth ◽  
Cell Populations ◽  
Sterile Phosphate Buffer ◽  
Food Contact Surfaces ◽  
Alkaline Conditions ◽  
Ph Conditions ◽  
Growth Ph ◽  
Holding Temperature

Attachment of Listeria monocytogenes Scott A to Buna-N rubber and stainless Steel under different temperature and pH conditions at the time of cell growth or at the time of attachment was investigated. AU experiments were conducted using sterile phosphate buffer to avoid cell growth during exposure to the test surfaces. Numbers of attached cells increased with increasing attachment temperature (10 to 45°C) and exposure time for both test surfaces. Maximum levels of attached cells were obtained when cell growth occurred at 30°C. Downward, but not upward, shifts in the cell suspension holding temperature prior to attachment to Buna-N rubber resulted in reduced adhered cell populations. Maximum levels of adhered cells to Buna-N rubber were not affected by adjustments of the attachment medium pH between 4 and 9. However, after short contact times (i.e., less than 30 min), levels of attached cells were lower when attachment occurred under alkaline conditions. Growth pH was also found to affect the levels of adhered cell populations to Buna-N rubber. L. monocytogenes Scott A attached to stainless Steel at higher levels for all temperature and pH parameters evaluated in this study.

Attachment of Listeria monocytogenes to an Austenitic Stainless Steel after Welding and Accelerated Corrosion Treatments

2006 ◽  
Vol 69 (7) ◽  
pp. 1527-1532 ◽  
Author(s):  
TAM L. MAI ◽  
NOFRIJON I. SOFYAN ◽  
JEFFREY W. FERGUS ◽  
WILLIAM F. GALE ◽  
DONALD E. CONNER
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Base Metal ◽  
Austenitic Stainless Steels ◽  
Bacterial Count ◽  
304 Stainless Steel ◽  
Test Surface ◽  
Accelerated Corrosion ◽  
Before And After ◽  
Type 304

Austenitic stainless steels, widely used in food processing, undergo microstructural changes during welding, resulting in three distinctive zones: weld metal, heat-affected zone, and base metal. This research was conducted to determine the attachment of Listeria monocytogenes in these three zones before and after exposure to a corrosive environment. All experiments were done with tungsten inert gas welding of type 304 stainless steel. The four welding treatments were large or small beads with high or low heat. After welding, all surfaces were polished to an equivalent surface finish. A 10-μl droplet of an L. monocytogenes suspension was placed on the test surfaces. After 3 h at 23°C, the surfaces were washed and prepared for scanning electron microscopy, which was used to determine attachment of L. monocytogenes by counting cells remaining on each test surface. In general, bacteria were randomly distributed on each surface type. However, differences in surface area of inoculum due to differences in interfacial energy (as manifested by the contact angle) were apparent and required normalization of bacterial count data. There were no differences (P > 0.05) in numbers of bacteria on the three surface zones. However, after exposure to the corrosive medium, numbers of bacteria on the three zones were higher (P < 0.05) than those on the corresponding zones of noncorroded surfaces. For the corroded surfaces, bacterial counts on the base metal were lower (P < 0.05) than those on heat-affected and weld zones.

Modulation of Cell Surface Hydrophobicity and Attachment of Bacteria to Abiotic Surfaces and Shrimp by Malaysian Herb Extracts

2012 ◽  
Vol 75 (8) ◽  
pp. 1507-1511 ◽  
Author(s):  
YEW WOH HUI ◽  
GARY A. DYKES
Keyword(s):  
Stainless Steel ◽  
Foodborne Pathogens ◽  
Salmonella Enteritidis ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Bacterial Attachment ◽  
Water Extracts ◽  
Bacterial Hydrophobicity ◽  
Herb Extracts ◽  
Herb Extract

The use of simple crude water extracts of common herbs to reduce bacterial attachment may be a cost-effective way to control bacterial foodborne pathogens, particularly in developing countries. The ability of water extracts of three common Malaysian herbs (Andrographis paniculata, Eurycoma longifolia, and Garcinia atroviridis) to modulate hydrophobicity and attachment to surfaces of five food-related bacterial strains (Bacillus cereus ATCC 14576, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 10145, Salmonella Enteritidis ATCC 13076, Staphylococcus aureus ATCC 25923) were determined. The bacterial attachment to hydrocarbon assay was used to determine bacterial hydrophobicity. Staining and direct microscopic counts were used to determine attachment of bacteria to glass and stainless steel. Plating on selective media was used to determine attachment of bacteria to shrimp. All extracts were capable of either significantly (P < 0.05) increasing or decreasing bacterial surface hydrophobicity, depending on the herb extract and bacteria combination. Bacterial attachment to all surfaces was either significantly (P < 0.05) increased or decreased, depending on the herb extract and bacteria combination. Overall, hydrophobicity did not show a significant correlation (P > 0.05) to bacterial attachment. For specific combinations of bacteria, surface material, and plant extract, significant correlations (R > 0.80) between hydrophobicity and attachment were observed. The highest of these was observed for S. aureus attachment to stainless steel and glass after treatment with the E. longifolia extract (R = 0.99, P < 0.01). The crude water herb extracts in this study were shown to have the potential to modulate specific bacterial and surface interactions and may, with further work, be useful for the simple and practical control of foodborne pathogens.

Effects of the Growth Procedure on the Surface Hydrophobicity of Listeria monocytogenes Cells and Their Adhesion to Stainless Steel

1999 ◽  
Vol 62 (9) ◽  
pp. 994-998 ◽  
Author(s):  
ROMAIN BRIANDET ◽  
VALERIE LERICHE ◽  
BRIGITTE CARPENTIER ◽  
MARIE-NOELLE BELLON-FONTAINE
Keyword(s):  
Stainless Steel ◽  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Electron Acceptor ◽  
Surface Hydrophobicity ◽  
Bacterial Attachment ◽  
Hydrophobic Properties ◽  
Cured Meat ◽  
The Media ◽  
Donor Characteristics

The aim of this study was to examine the physicochemical surface properties and the ability to adhere to stainless steel of three strains of Listeria monocytogenes after different cultivation procedures. To this end, bacteria were cultivated at 37°C after storage at two frequently used temperatures (4°C or −80°C) and were then transferred into the liquid medium (trypticase soy broth supplemented with 6 g liter−1 of yeast extract, pH 7.3) between one and four times. In addition, the influence of supplementing the growth medium with lactic acid was explored, this organic acid being representative of both the dairy and cured meat industries. The hydrophobic/hydrophilic and electron-acceptor/electron-donor characteristics of the strains were evaluated by the microbial adhesion to solvents method. Using this technique, we recorded an increase in the hydrophobic properties of one strain stored at 4°C, with an increasing number of transfers in the media (P < 0.05). Another plant-isolated strain appeared more hydrophobic and stuck better to stainless steel when cells were stored at 4°C rather than at −80°C. Preculturing L. monocytogenes in a lactic acid-supplemented medium increased the affinity of microbial cells to solvents and the bacterial attachment to stainless steel (P < 0.05).

Attachment of Listeria monocytogenes on Ready-to-Eat Meats

2004 ◽  
Vol 67 (3) ◽  
pp. 456-462 ◽  
Author(s):  
SALLY C. C. FOONG ◽  
JAMES S. DICKSON
Keyword(s):  
Contact Angle ◽  
Listeria Monocytogenes ◽  
Cell Surface ◽  
Bacterial Cell ◽  
Negative Charge ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Roast Beef

Five individual strains of Listeria monocytogenes and a mixed cocktail of all five were studied for attachment on frankfurters, ham, bologna, and roast beef relative to their cell surface characteristics. The ratio of strongly attached (sessile) L. monocytogenes cells compared with total (sessile and planktonic) attached cells on ready-to-eat meats was also determined. Because bacterial cell surfaces were characterized by net negative charge and hydrophobicity, electrostatic interaction chromatography and cationized ferritin methods were chosen to study net negative charge distribution on the bacterial cell surface, whereas hydrophobic interaction chromatography and contact angle measurement were used to examine the cell surface hydrophobicity. No differences (P > 0.05) were observed in cell surface charge or cell surface hydrophobicity among strains. Approximately 84 to 87% L. monocytogenes were found to attach strongly to ready-to-eat meats within 5 min. No differences (P > 0.05) were found among strains or among meats. Micrographs observed from scanning electron microscopy showed no differences among the strains but showed a difference in age of cells (mixed culture) in terms of surface negative charge distribution. More surface negatively charged sites were observed at 0 and 7 days and much fewer at 3 days during storage of washed, harvested cells in buffer at 4°C (aged cells under cold and nutrient deprivation), indicating a possible change in cell surface properties. Because no difference in strains was observed, the contact angle measurement study was carried out with the five-strain mixed culture. The surface hydrophobicity increased in frankfurters, decreased in roast beef, and was unchanged in ham and bologna as a result of inoculation.

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