The detection of food soils on stainless steel using energy dispersive X-ray and Fourier transform infrared spectroscopy

The Removal of Meat Exudate and Escherichia coli from Stainless Steel and Titanium Surfaces with Irregular and Regular Linear Topographies

Bacterial retention and organic fouling on meat preparation surfaces can be influenced by several factors. Surfaces with linear topographies and defined chemistries were used to determine how the orientation of the surface features affected cleaning efficacy. Fine polished (irregular linear) stainless steel (FPSS), titanium coated fine polished (irregular linear) stainless steel (TiFP), and topographically regular, linear titanium coated surfaces (RG) were fouled with Escherichia coli mixed with a meat exudate (which was utilised as a conditioning film). Surfaces were cleaned along or perpendicular to the linear features for one, five, or ten wipes. The bacteria were most easily removed from the titanium coated and regular featured surfaces. The direction of cleaning (along or perpendicular to the surface features) did not influence the amount of bacteria retained, but meat extract was more easily removed from the surfaces when cleaned in the direction along the linear surface features. Following ten cleans, there was no significant difference in the amount of cells or meat exudate retained on the surfaces cleaned in either direction. This study demonstrated that for the E. coli cells, the TiFP and RG surfaces were easiest to clean. However, the direction of the clean was important for the removal of the meat exudate from the surfaces.

Differential engulfment of Staphylococcus aureus and Pseudomonas aeruginosa by monocyte-derived macrophages is associated with altered phagocyte biochemistry and morphology

Knowledge of changes in macrophages following bacterial engulfment is limited. U937-derived macrophages were incubated with Staphylococcus aureus or Pseudomonas aeruginosa. Morphological and biochemical changes in macrophages following host-pathogen interactions were visualized using Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared Spectroscopy (FTIR) respectively. Principal Component Analysis (PCA) was used to assess the variability in the FTIR spectra. Following host-pathogen interactions, survival of S. aureus was significantly lower than P. aeruginosa (P<0.05) and cellular morphology of macrophages was different after incubation with S. aureus compared to P. aeruginosa. Following incubation with S. aureus macrophages were more globular and amorphous in shape whereas long linear pseudopodia were observed following incubation with P. aeruginosa. Distinct FTIR spectra were identified in macrophages post interaction with the different bacteria and PCA analysis demonstrated distinct biochemical differences in the phagocytes following engulfment of the bacteria, with > 99 % of variability in the FTIR spectra explained by the first two principal components. These findings demonstrated that there were clear morphological and biochemical changes in macrophages following engulfment of two different bacterial types suggesting that the biochemical components of the bacterial cell wall influenced the biochemical characteristics and hence the morphology of macrophages in distinct ways.

Phosphorus removal from aqueous solution in parent and aluminum-modified eggshells: thermodynamics and kinetics, adsorption mechanism, and diffusion process

Parent and aluminum-modified eggshells were prepared and characterized with X-ray diffraction, specific surface area measurements, infrared spectroscopy, zeta potential, and scanning electron microscope, respectively. Besides, phosphorus adsorptions in these two eggshells at different temperatures and solution pH were carried out to study adsorption thermodynamics and kinetics as well as the mechanisms of phosphorus adsorption and diffusion. The results indicated that high temperature was favorable for phosphorus adsorption in parent and aluminum-modified eggshells. Alkaline solution prompted phosphorus adsorption in parent eggshell, while the maximum adsorption amount was achievable at pH 4 in aluminum-modified eggshell. Adsorption isotherms of phosphorus in these eggshells could be well described by Langmuir and Freundlich models. Phosphorus adsorption amounts in aluminum-modified eggshell were markedly higher compared to those in parent eggshell. Adsorption heat indicated that phosphorus adsorption in parent eggshell was a typically physical adsorption process, while chemical adsorption mechanism of ion exchange between phosphorus and hydroxyl groups on the surface of eggshells was dominated in aluminum-modified eggshell. The time-resolved uptake curves showed phosphorus adsorption in aluminum-modified eggshell was significantly faster than that in parent eggshell. Moreover, there existed two clear steps in time-resolved uptake curves of phosphorus in parent eggshell. Based on pseudo-second order kinetic model and intraparticle diffusion model, we inferred more than one process affected phosphorus adsorption. The first process was the diffusion of phosphorus through water to external surface and the opening of pore channel in the eggshells, and the second process was mainly related to intraparticle diffusion.

Influence of milling on the adsorption ability of eggshell waste

Eggshell waste was successfully used for the removal of heavy metal ions from model solutions. The effect of ball milling on the structure and adsorption ability of eggshell (ES) and its membrane (ESM) was investigated, with the conclusion that milling is benefitial only for the ES. The adsorption experiments showed that the ESM is a selective adsorbent, as the adsorption ability toward different ions decreased in the following order: Ag(I) > Cd(II) > Zn(II). The obtained Qm values for Ag(I) adsorption on the ESM and ES were 52.9 and 55.7 mg g(-1), respectively. The potential industrial application of ES was also demonstrated by successful removal of Ag(I) from the technological waste.

Eggshell membrane biomaterial as a platform for applications in materials science

Eggshell membrane (ESM) is a unique biomaterial, which is generally considered as waste. However, it has extraordinary properties which can be utilized in various fields and its potential applications are therefore now being widely studied. The first part of this review focuses on the chemical composition and morphology of ESM. The main areas of ESM application are discussed in the second part. These applications include its utilization as a biotemplate for the synthesis of nanoparticles; as a sorbent of heavy metals, organics, dyes, sulfonates and fluorides; as the main component of biosensors; in medicine; and various other applications. For each area of interest, a detailed literature survey is given.

Layer-by-layer deposition of antifouling coatings on stainless steel via catechol-amine reaction

The PEI/P(DMA-co-PEGMEMA) multiple bilayer-coated surfaces can effectively reduce microfouling and macrofouling.

Review--Interactions between diatoms and stainless steel: focus on biofouling and biocorrosion

There is a considerable body of information regarding bacterially enhanced corrosion, however, this review focuses on diatoms (unicellular algae) whose contribution to biocorrosion is less well studied. The reasons why diatoms have been neglected in studies of biocorrosion in natural waters are discussed and the question whether diatoms should be considered as inert with respect of electrochemical processes is considered. A particular focus is given to the case of stainless steels (SS), which are widely used in variety of applications in natural waters. Basic information on the cell biology of diatoms is included in the review, particularly with respect to their ability to 'sense' and adhere to surfaces. Investigations at the nanoscale are reviewed as these studies provide information about the behavior of cells at interfaces. Recent advances include the use of atomic force microscopy (AFM), although only a few studies have been applied to diatoms. Regarding the electrochemical behavior of SS, the mechanisms by which diatoms influence the potential ennoblement process is discussed. Such studies reveal the association of diatoms, in addition to bacteria, with biocorrosion processes.