Syllabus of the workshop physicochemical characterization of nano-sized particles in food

Scope of this&nbsp;workshop Training on the measurement approach for the physicochemical characterization of nano-sized particles in food additives (including E171 and E174) and in food products by TEM Practical experience in sample/TEM-specimen preparation and application of the ParticleSizer software for the analysis of TEM&nbsp;images. Demonstration of the analytical capacities of state-of-the-art methodologies to implement guidance and legislation based on (automated) analytical TEM. &nbsp; </ul

Increased density of Demodex folliculorum and evidence of delayed hypersensitivity reaction in subjects with papulopustular rosacea

Background Rosacea is a common chronic dermatosis that evolves in stages. The mite Demodex folliculorum has been implicated in its obscure aetiopathogenesis. Aim To evaluate the importance of D. folliculorum in the aetiology and course of rosacea. Methods We studied 92 consecutive cases of papulopustular rosacea and 92 age- and sex-matched controls. Prevalence and density of D. folliculorum were estimated by microscopic examination of the expressed follicular content. Histological examination and immunohistochemical study of the inflammatory infiltrate were performed in 10 subjects (five with positive D. folliculorum finding and five with negative finding). Results D. folliculorum was detected in 83 (90.2%) of the 92 rosacea subjects but only 11 (11.9%). of the controls. The mean mite density was 2.03 mites/visual field in the rosacea group (range 0-5, SD = 1.2) and 0.16 mites/visual field (range 0-2, SID = 0.52) in the control group. The difference was statistically significant (P &lt; 0.0001) for both mite prevalence and density. Hair follicle infestation was associated with intense perifollicular infiltrate of predominantly (90-95%) CD4 helper/inducer T cells. We observed an increased number of macrophages and Langerhans cells only in those subjects with a positive D. folliculorum finding. Conclusions Although Demodex mites do not seem to be the cause of rosacea, they may represent an important cofactor, especially in papulopustular rosacea. Immunohistochemical findings suggest that a delayed hypersensitivity reaction, possibly triggered by antigens of follicular origin, probably related to D. folliculorum, may occur, stimulating progression of the affection to the papulopustular stage

Identification and characterization of inorganic food additives and pearlescent pigments in sprays for food decoration by STEM-EDX

Food colorants are applied in commercial products and domestic cooking to enhance the appearance of food. To obtain specific hues, inorganic food additives containing (nano)particles are mixed in varying concentrations, and pearlescent pigments consisting of mica platelets coated with a layer of titanium dioxide and/or iron oxide particles, are applied to provide glitter effects1. For control and risk assessment of multi-constituent substances and mixtures, characterisation of the fraction of small particles, including the particle size distribution, is needed for each single constituent or each component in the mixture2. This is challenging for control laboratories and only limited guidance is currently available3. This study developed electron microscopy-based methods to identify and characterize the particles of individual components in eight commercially available food-decoration sprays of different colours, containing mixtures of food additives and pearlescent pigments. No dispersion protocols or purifications steps were applied to optimally assess the properties of the particles consumers are exposed to. Samples were prepared by spraying 5mL in a glass vial and coated on EM-grids using the grid-on-drop method. Scanning transmission electron microscopy (STEM) combined with energy dispersive X-ray spectroscopy (EDX) allowed identifying particles of separate components, including potassium aluminium silicate-based pearlescent pigments, vegetable carbon, rutile titanium dioxide (nano)particles, iron oxide (nano)particles and aluminium containing (nano)particles by their elemental composition. Their presence and relative concentration varied between spray colours. Often the layer of titanium dioxide particles detached from the mica, and titanium dioxide particles were also observed forming near-spherical aggregates. STEM-EDX tomography allowed identifying particles of overlapping components and examining the structure of the pearlescent pigments in 3D. The presence of a fraction of nanoparticles in each component was demonstrated based on their particle size distributions. The methods and findings support regulatory bodies to assess and control possible health risks of mixtures of (nano)particles present in the food&nbsp;chain.</p