scholarly journals EFFECT OF SOLUTE CONCENTRATION AND PRE-SOIL INTERACTION ON THE MICROFLORA OF DAIRY ORIGIN ON STAINLESS STEEL SURFACES1

1970 ◽  
Vol 33 (12) ◽  
pp. 541-544 ◽  
Author(s):  
H. M. Barnhart ◽  
R. B. Maxcy ◽  
C. E. Georgi
Keyword(s):  
Stainless Steel ◽  
Water Loss ◽  
Food Processing ◽  
Solute Concentration ◽  
Moisture Loss ◽  
Stainless Steel Surface ◽  
Dairy Food ◽  
Temperature And Humidity ◽  
Closed Systems ◽  
Steel Surfaces

Use of modern dairy food processing equipment creates a complex microenvironment. Closed systems reduce air drying. The rate and extent of drying are dependent on temperature and humidity of the environment. These factors were studied to determine their impact on the microflora of films of milk on stainless steel surfaces. An ecosystem was established to simulate dairy food equipment by using 1cm2 pieces of stainless steel in controlled humidity chambers. Presoiling water loss from a film of milk, and solute concentration were studied to determine their influence on the fate of the microflora. Temperature and humidity of the atmosphere influenced the rate of moisture loss from films. Pre-soiling reduced the rate of water loss from films of milk sufficiently to allow bacterial growth at 12–80% relative humidity (RH). Results indicate bacteria can grow in a film placed in humidities well below the 95% RH limit previously projected. Apparently the substrate is influenced by interaction of the milk film and the stainless steel surface.

Destruction of Alicyclobacillus acidoterrestris Spores in Apple Juice on Stainless Steel Surfaces by Chemical Disinfectants

2009 ◽  
Vol 72 (3) ◽  
pp. 510-514 ◽  
Author(s):  
RICHARD PODOLAK ◽  
PHILIP H. ELLIOTT ◽  
BRADLEY J. TAYLOR ◽  
AAKASH KHURANA ◽  
DARRYL G. BLACK
Keyword(s):  
Stainless Steel ◽  
Chlorine Dioxide ◽  
Apple Juice ◽  
Octanoic Acid ◽  
Stainless Steel Surface ◽  
Peroxyacetic Acid ◽  
Alicyclobacillus Acidoterrestris ◽  
Practical Applications ◽  
Maximum Reduction ◽  
Steel Surfaces

A study was conducted to determine the effects of three commercially available disinfectants on the reduction of Alicyclobacillus acidoterrestris spores in single-strength apple juice applied to stainless steel surfaces. Apple juice was inoculated with A. acidoterrestris spores, spread onto the surface of stainless steel chips (SSC), dried to obtain spore concentrations of approximately 104 CFU/cm2, and treated with disinfectants at temperatures ranging from 40 to 90°C. The concentrations of disinfectants were 200, 500, 1,000, and 2,000 ppm of total chlorine for Clorox (CL) (sodium hypochlorite); 50, 100, and 200 ppm of total chlorine for Carnebon 200 (stabilized chlorine dioxide); and 1,500, 2,000, and 2,600 ppm for Vortexx (VOR) (hydrogen peroxide, peroxyacetic acid, and octanoic acid). For all temperatures tested, VOR at 2,600 ppm (90°C) and CL at 2,000 ppm (90°C) were the most inhibitory against A. acidoterrestris spores, resulting in 2.55- and 2.32-log CFU/cm2 reductions, respectively, after 2 min. All disinfectants and conditions tested resulted in the inactivation of A. acidoterrestris spores, with a maximum reduction of >2 log CFU/cm2. Results from this study indicate that A. acidoterrestris spores, in single-strength apple juice, may be effectively reduced on stainless steel surface by VOR and CL, which may have practical applications in the juice industry.

Scanning Electron Microscopic Examination of Yersinia enterocolitica Attached to Stainless Steel at Selected Temperatures and pH values1

1988 ◽  
Vol 51 (6) ◽  
pp. 445-448 ◽  
Author(s):  
PAULA J. HERALD ◽  
EDMUND A. ZOTTOLA
Keyword(s):  
Stainless Steel ◽  
Yersinia Enterocolitica ◽  
Steel Surface ◽  
Electron Microscopic Examination ◽  
Growth Conditions ◽  
Stainless Steel Surface ◽  
Electron Microscopic ◽  
Scanning Electron Microscopic ◽  
Steel Surfaces ◽  
Scanning Electron

Attachment of Yersinia enterocolitica to stainless steel surfaces at 35, 21, and 10°C was investigated using scanning electron microscopy (SEM). Cells adhered at all three temperatures, but, in general, the greatest number of adhered cells were observed at pH 8 and 21°C. Multi-flagellated cells were noted under these growth conditions. When grown at pH 9.5 and 21°C, fibrils were observed between cells and extending to the stainless steel surface. Fewer cells with flagella were seen at this pH. Adherence may be related to the flagella and any exopolymer surrounding the cells.

Comparison of Nucleation Site Density for Pool Boiling and Gas Nucleation

2005 ◽  
Vol 128 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Yusen Qi ◽  
James F. Klausner
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Pool Boiling ◽  
Nucleation Site ◽  
Stainless Steel Surface ◽  
Distilled Water ◽  
Site Density ◽  
Significant Difference ◽  
Steel Surfaces ◽  
Nucleation Site Density

It has been well established that the rate of heat transfer associated with boiling systems is strongly dependent on the nucleation site density. Over many years attempts have been made to predict nucleation site density in boiling systems using a variety of techniques. With the exception of specially prepared surfaces, these attempts have met with little success. This paper presents an experimental investigation of nucleation site density measured on roughly polished brass and stainless steel surfaces for gas nucleation and pool boiling over a large parameter space. A statistical model used to predict the nucleation site density in saturated pool boiling is also investigated. The fluids used for this study, distilled water and ethanol, are moderately wetting and highly wetting, respectively. Using distilled water it has been observed that the trends of nucleation site density versus the inverse of the critical radius are similar for pool boiling and gas nucleation. The nucleation site density is higher for gas nucleation than for pool boiling. An unexpected result has been observed with ethanol as the heat transfer fluid, which casts doubt on the general assumption that heterogeneous nucleation in boiling systems is exclusively seeded by vapor trapping cavities. Due to flooding, few sites are active on the brass surface and at most two are active on the stainless steel surface during gas nucleation experiments. However, nucleation sites readily form in large concentration on both the brass and stainless steel surfaces during pool boiling. The pool boiling nucleation site densities for ethanol on rough and mirror polished brass surfaces are also compared. It shows that there is not a significant difference between the measured nucleation site densities on the smooth and rough surfaces. These results suggest that, in addition to vapor trapping cavities, another mechanism must exist to seed vapor bubble growth in boiling systems.

Modification of stainless steel surface hydrophobicity by silver nanoparticles: strategies to prevent bacterial adhesion in the food processing

2013 ◽  
Vol 27 (24) ◽  
pp. 2686-2695 ◽  
Author(s):  
Emiliane Andrade Araújo ◽  
Nélio José de Andrade ◽  
Luis Henrique Mendes da Silva ◽  
Patrícia Campos Bernardes ◽  
Álvaro Vianna Novaes de Carvalho Teixeira ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Stainless Steel ◽  
Food Processing ◽  
Bacterial Adhesion ◽  
Steel Surface ◽  
Surface Hydrophobicity ◽  
Stainless Steel Surface

A model heat-exchange apparatus for the investigation of fouling of stainless steel surfaces by milk I. Deposit formation at 100 °C

1989 ◽  
Vol 56 (2) ◽  
pp. 201-209 ◽  
Author(s):  
Carole L. Foster ◽  
Michel Britten ◽  
Margaret L. Green
Keyword(s):  
Stainless Steel ◽  
Heat Exchange ◽  
Time Course ◽  
Small Scale ◽  
Lag Phase ◽  
Stainless Steel Surface ◽  
Deposit Formation ◽  
Factors Affecting ◽  
Steel Surfaces ◽  
Exchange Apparatus

SummaryA model heat-exchange apparatus was used to investigate the factors affecting deposit formation from milk on a stainless steel surface at 100 °C. The structure and composition of the deposits were determined by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and chemical analysis after solution in alkali. The effects of changing the pH, preheating and skimming of the milk were similar to those observed in a small-scale continuous ultra high temperature plant. The time course of deposit formation showed that a lag phase did not occur, but the deposit which formed after more than 45 min was more porous than that formed after shorter times. Most (50–90%) of the fresh deposit was readily removed by sonication, leaving a sublayer richer in minerais than the original. The results provide evidence for the two-layer model for deposit formation proposed by Tissier & Lalande (1986).

Improved Quantitative Recovery of Listeria monocytogenes from Stainless Steel Surfaces Using a One-Ply Composite Tissue

2004 ◽  
Vol 67 (10) ◽  
pp. 2212-2217 ◽  
Author(s):  
KEITH L. VORST ◽  
EWEN C. D. TODD ◽  
ELLIOT T. RYSER
Keyword(s):  
Stainless Steel ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Steel Plates ◽  
Stainless Steel Surface ◽  
Disc Diffusion ◽  
Buffer Solution ◽  
Composite Tissue ◽  
Steel Surfaces ◽  
Diffusion Assay

Four sampling devices, a sterile environmental sponge (ES), a sterile cotton-tipped swab (CS), a sterile calcium alginate fiber-tipped swab (CAS), and a one-ply composite tissue (CT), were evaluated for quantitative recovery of Listeria monocytogenes from a food-grade stainless steel surface. Sterile 304-grade stainless steel plates (6 by 6 cm) were inoculated with approximately 106 CFU/cm2 L. monocytogenes strain Scott A and dried for 1 h. The ES and CT sampling devices were rehydrated in phosphate buffer solution. After plate swabbing, ES and CT were placed in 40 ml of phosphate buffer solution, stomached for 1 min and hand massaged for 30 s. Each CS and CAS device was rehydrated in 0.1% peptone before swabbing. After swabbing, CS and CAS were vortexed in 0.1% peptone for 1 min. Samples were spiral plated on modified Oxford agar with modified Oxford agar Rodac Contact plates used to recover any remaining cells from the stainless steel surface. Potential inhibition from CT was examined in both phosphate buffer solution and in a modified disc-diffusion assay. Recovery was 2.70, 1.34, and 0.62 log greater using CT compared with ES, CS, and CAS, respectively, with these differences statistically significant (P < 0.001) for ES and CT and for CAS, CS, and CT (P < 0.05). Rodac plates were typically overgrown following ES, positive after CS and CAS, and negative after CT sampling. CT was noninhibitory in both phosphate buffer solution and the modified disc-diffusion assay. Using scanning electron microscopy, Listeria cells were observed on stainless steel plates sampled with each sampling device except CT. The CT device, which is inexpensive and easy to use, represents a major improvement over other methods in quantifying L. monocytogenes on stainless steel surfaces and is likely applicable to enrichment of environmental samples.

scholarly journals Durable Polymeric N-halamine Functionalized Stainless Steel Surface for Improved Antibacterial and Anti-biofilm Activity

2021 ◽  
Author(s):  
Rajani Kant Rai ◽  
Hemalatha Kanniyappan ◽  
Vignesh Muthuvijayan ◽  
Venkitasamy Kesavan ◽  
A. Jayakrishnan
Keyword(s):  
Stainless Steel ◽  
Water Purification ◽  
Food Processing ◽  
Bacterial Adhesion ◽  
Steel Surface ◽  
Antibacterial Properties ◽  
Orthopedic Implants ◽  
Surgical Instruments ◽  
Stainless Steel Surface

Bacterial adhesion and colonization on stainless steel (SS) based surgical instruments, hospital equipments, orthopedic implants, water purification and food processing units are a major problem. Imparting rechargeable antibacterial properties to...

scholarly journals Clean in place (CIP) of different stainless steel geometries contaminated with Pseudomonas fluorescens

2020 ◽  
Vol 9 (12) ◽  
pp. e23491210866
Author(s):  
Lucas Donizete Silva ◽  
Maíra Gontijo Moreira ◽  
Natália Trindade Guerra ◽  
Emiliane Araújo Andrade Naves ◽  
Priscila Cristina Bizam Vianna ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Stainless Steel ◽  
Food Processing ◽  
Steel Surface ◽  
Economic Damage ◽  
Stainless Steel Surface ◽  
Initial Population ◽  
Surface Sampling ◽  
Fluent Software ◽  
Alkaline Cleaning

The presence of biofilms on food processing surfaces is a constant concern and can cause economic damage and impacts on public health. The aim of this work was to evaluate the development of P. fluorescens on the stainless steel surface, to analyze the CIP (clean in place) hygiene considering different geometries, to investigate the flow fluid dynamics and to determine the consumption of the inputs in this process. A circulation line with the characteristics of a dairy was used. The surface sampling was done using the swab technique and the performance of the process was evaluated based on decimal reductions considering the initial population adhered. The fluid dynamics study was carried out with FLUENT software and the consumption was determined by means of flow and electric current sensors. The results showed that P. fluorescens adhered to the surface reaching an average of 4.31 ± 0.26 log CFU∙cm-2, with the production of exopolysaccharides during usual time of industry operation. The decimal reduction was not significantly different among the pipe geometries in straight section, elbow, expansion and reduction. The stretch with branching in tee was statistically different from the others due to a zone of stagnation and fluid recirculation. The rinses were the stages that consumed the most water and the alkaline cleaning demanded more energy to execute the CIP. The geometries showed microbiological safety after CIP process, except tee. In addition, the expressive demand for water and energy for the execution of the process was evident.

FACTORS IN THE ECOSYSTEM OF FOOD PROCESSING EQUIPMENT CONTRIBUTING TO OUTGROWTH OF MICROORGANISMS ON STAINLESS STEEL SURFACES1

1971 ◽  
Vol 34 (12) ◽  
pp. 569-573 ◽  
Author(s):  
R. B. Maxcy
Keyword(s):  
Stainless Steel ◽  
Water Loss ◽  
Raw Milk ◽  
Solute Concentration ◽  
Plate Count ◽  
Laboratory System ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Sterile Phosphate Buffer ◽  
Mechanical Handling

A laboratory system using 1 cm2 pieces of stainless steel with controlled temperature, humidity, and inocula was used to study the fate of the microflora of dairy origin on various films. Metal squares were treated to simulate incomplete cleaning, then inoculated with raw milk. After incubation for 16 hr at 80, 86, 93, or 100% RH, the microflora was recovered in sterile phosphate buffer and evaluated using the standard plate count method. Isolates from countable plates were observed for general characterization. Humidity of the ecosystem was a major factor in rate of water loss from a film. Available water, and indirectly the solute concentration, influenced the microenvironment and the resulting population density of microorganisms. Likewise, the microenvironment had a selective effect on outgrowth of bacteria, because of varying sensitivity of bacteria to drying and solute concentration. The gram-negative bacteria were inhibited at a lower humidity (80% RH), while the higher humidities (93 or 100% RH) provided sufficient water for abundant outgrowth. Reduction of area of a film exposed to air reduced water loss and provided protection for harborage of microorganisms. Pre-soiling prior to addition of a film of milk decreased the rate of water loss from the film and increased bacterial growth. Induced lipolysis within a film of milk influenced outgrowth of bacteria with an inhibitory effect on gram-positive types. Results indicate that modem closed systems and extensive mechanical handling of milk may be favoring growth of undesirable gram-negative bacteria, e.g., coliforms and psychrotrophs.

The influence of chemical cleaning methods on pitting morphology attributed to microbially influenced corrosion of stainless steels

CORROSION ◽  
10.5006/3707 ◽  
2020 ◽  
Author(s):  
Muhammad Awais Javed ◽  
Nathaniel Rieders ◽  
Iwona Beech ◽  
Recep Avci ◽  
Wayne Neil ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Stainless Steel Surface ◽  
Metallic Materials ◽  
Chemical Cleaning ◽  
Microbially Influenced Corrosion ◽  
Quantitative Measurements ◽  
Treatment Type ◽  
Steel Surfaces ◽  
Potential Impact ◽  
Cleaning Methods

Chemical cleaning methods are frequently employed for the removal of biofilm/corrosion products from metallic materials to evaluate the type and severity of microbially influenced corrosion (MIC) damage. The study described here investigates the effect of commonly applied cleaning treatments on the dissolution of stainless steel surface inclusions and emphasizes the potential impact of such treatments on MIC diagnostics. Polished 304 grade stainless steel coupons were ultrasonicated for 1, 3 and 7 min in each of the three commonly applied agents, i.e. Clarke’s, nitric acid and hydrofluoric acid-based solutions. Post-treatment analyses of steel surfaces revealed pitting attack. For each treatment type and duration, the morphology and quantitative measurements of pits were recorded. Shape, size and depth of examined pits closely resembled damage that, in many laboratory-based studies, have been attributed to MIC. The investigation herein demonstrates that caution ought to be exerted when implicating MIC as the cause of stainless steel pitting damage.

Sign in / Sign up

Export Citation Format

Share Document